BUNGE INDUSTRIAL STEELS PTY. LIMITED

BISALLOY

TECHNICAL ASSISTANCE MANUAL

THIS MANUAL ALWAYS REMAINS THE PROPERTY OF BUNGE INDUSTRIAL STEELS PTY. LIMITED AND MUST BE RETURNED ON REQUEST. The information contained in this publication has been prepared as accurately as possible, however, data is given for guidance and the Company will in no way accept liability.

6/84 Page 1

INTRODUCTION

Perhaps once or twice in a generation a product is launched which pioneers a new phase of development in a particular industry. Born out of necessity during World War II, the restricted supply of high alloy armour plate led to the discovery that steels with armour plate properties could be produced with much lower alloy content by quenching and tempering.

This original concept was further refined by the U.S. Steel Corporation to produce the weldable grades of Ti steels. The T1 steels are a low carbon multiple alloy boron containing steel with 690 MPa minimum yield strength in the quench and tempered condition.

Quench and tempered steels are now used extensively in construction equipment, earth moving equipment, bridges, booms and dipper sticks, cranes, penstocks, shipping, radio and TV towers, road and rail tankers, buildings and pressure vessels. Higher carbon varieties, which are readily welded, are also used extensively in abrasive conditions with hardness up to BHN 525.

Until 1980, all quenched and tempered low alloy steels used in Australia were imported. However, the opening of Bunge Industrial Steels' plant at Unanderra in that year meant that this advanced alloying and heat treatment technology was available in Australia.

6/84 Page 2

THE UNANDERRA PLANT Resolution Drive, UNANDERRA. 2526.

New South Wales, Australia.

BUNGE INDUSTRIAL STEELS PTY. LIMITED P.O. Box 231, UNANDERRA. 2526. NSW. Australia.

Telephone: (042) 71-4944 Telex: AA29227

3. Specifications of Bisalloy Steels

1. Mechanical Properties of Steels

5. Welding of Bisalloy Steels

7. Application of Bisalloy Grades

8. Technical Literature

6/84 Page 4

SECTION ONE

MECHANICAL PROPERTIES OF STEELS

1.1 Hardness

1.2 Brinell Hardness Test

1.3 Tensile Test

1.4 Tensile Properties 1.4.1 Elastic Limit 1.4.2 Yield Point 1.4.3 Yield Strength 1.4.4 Tensile Strength 1.4.5 Fracture Strength

1.5 Ductility 1.5.1 Elongation 1.5.2 Reduction in Area

1.6 Charpy Impact Test

6/84 Si: Page 1

MECHANICAL PROPERTIES OF STEELS

1.1 HARDNESS The property of "hardness" is

difficult to define, except in relation to a particular test used to determine its value.

Hardness is not a fundamental property of material, but is related to the elastic and plastic properties. The hardness value obtained in a particular test serves only as a comparison between materials or process treatments. Hardness usually implies a resistance to deformation and, for steels, the property is a measure of the resistance to permanent or plastic deformation.

The test procedure and sample preparation are usually simple, and the results may be used in estimating other mechanical properties. Hardness testing is widely used for inspection and control, where heat treatment, or working the steel, results in a change of hardness.

A hardness value is particularly useful in determining the wear resistant properties of steels. High hardness values result in a higher abrasive resistant material. Most wear resistant steels are ranked in order of hardness.

1.2 BRINELL HARDNESS TEST

The Brinell hardness test consists of indenting the steel surface with a 10mm diameter steel ball at a load of 3,000kg. The test is conducted under AS1816-1977, which specifies testing conditions.

The Brinell hardness number (BHN) is expressed as the load P divided by the surface area of indentation, and is given by: BHN

77-D (D 02 d2 ) 2 where P = load applied, kg

D = diameter of ball, mm d = diameter at indentation, mm

Calculation is unnecessary, due to availability of conversion tables which give hardness values as a function at the measured d.

1.3 TENSILE TEST The tensile test is widely used to

provide basic design information on the strength of materials and as an acceptance test for the specification of materials.

Tensile tests are conducted to AS1391-1974. The standard specifies specimen sizes, test conditions and staff requirements. A test specimen is placed under a continually increasing load. Observations are made of the load and extension of the test specimen.

Observations are usually taken in the graphic form by a recorder attached to the tensile machine. The graph, load versus extension, can be examined to determine tensile properties such as elastic limit, yield point, yield strength, tensile strength and fracture strength. From the test specimen, ductility properties, such as elongation and reduction in area, can be determined.

1.4 TENSILE PROPERTIES

The properties which may be determined by a tensile test are as follows:

1.4.1 ELASTIC LIMIT It is found for many structural

materials the early part of the load-elongation graph is a straight line (linear). The load and extension are proportional to each other. Any increase in load results in a proportional increase in elongation of the specimen. If the load is removed, the specimen returns to its original dimensions, thus elastic behaviour has been displayed by the material. If the load is continuously increased, a point will be reached at which permanent elongation will result.

6/84 S1: Page 2

ELASTIC PLASTIC BEHAVIOUR BEHAVIOUR

UNIFORM M LOCALISED

a

The stress of any point is the load divided by the original cross sectional area while strain is the extension of that point divided by the original length.

The elastic limit is defined as the minimum stress at which permanent deformation first occurs, as seen in Fig. 1.4a.

ELONGATION Fig. 1.4a. Load versus elongation graph where Y = Yield Point or Elastic Limit

M = Tensile Strength F = Fracture Strength X = Proof Stress

1.4.2 YIELD POINT The stress at Point Y, Fig. 1.4a, is

known as the yield point. This phenomenon occurs only in certain ductile materials where there is a sudden discontinuity in the load versus extension curve. If the material is loaded above this limit, permanent deformation will result.

1.4.3 YIELD STRENGTH Most high strength steels do not

possess a well-defined yield point. For those materials, the maximum useful strength is the yield strength. The yield strength is the load required to produce a small amount of plastic deformation. The usual definition of this property is the offset yield strength (proof stress), determined by the stress corresponding to the intersection of the curve at an offset value, e.g. 0.2%.

The stress at which the steel begins to flow plastically (non-linear section) is an important feature, because it can be used to calculate the load at which permanent deformation results. In engineering design, it is always imperative that components retain their original dimensions. Thus the yield strength is the most important result from tensile tests.

1.4.4 TENSILE STRENGTH The tensile strength is the maximum

stress developed by the material point M.

1.4.5 FRACTURE STRENGTH Fracture is the separation of a solid

body into two or more parts under the action of stress. A ductile fracture is characterised by appreciable plastic deformation, both uniform and localised. After the maximum stress is reached (TS), localised deformation occurs, resulting in the necking of the specimen. The fracture strength is the stress at the point of failure of the specimen. It is always less than the tensile strength. In brittle fractures, little necking occurs. In practical design it is of little consequence.

1.5 DUCTILITY The ductility of a material is indicated

by the amount of deformation that is possible until fracture. This is determined in a tension test by two measurements.

1.5.1 ELONGATION This is determined by fitting together,

after fracture, the parts of the specimen and measuring the distance between the original gauge marks.

Elongation "'L f Lo

x 100 (per cent)

where Lf= final gauge length

L0 original gauge length (usually 50mm)

In reporting per cent elongation, the original gauge length must be specified, since the per cent elongation will vary with gauge length.

1.5.2 REDUCTION IN AREA This is also determined from the

broken halves of the tensile specimen by measuring the minimum cross-sectional area and using the following formula:

Aci- A f Reduction in Area = x 100 (per cent) A

o

where A = original cross-sectional area Af= final cross-sectional area

Lo

6/84

S1:Page 3

KNIFE EDGE MOUNTED IN A WEIGHTED PENDULUM HAMMER

low -150 .100

50 50 100 TEMPERATURE, "C

IMP A

CT ST

R ENG

T H

high

BRITTLE FRACTURE

DUCTILE FRACTURE

as a beam in a horizontal position and loaded behind the notch by the impact of a heavy swinging pendulum. The specimen is forced to bend and fracture at a high strain rate.

1.6 CHARPY IMPACT TEST

Structural steel is usually ductile at atmospheric temperatures. However, some of the most disastrous and tragic of engineering failures, such as the complete break-up of ships, bridges and pressure vessels, have been caused by the brittle fracture of steel. Such fractures come without warning and take place very rapidly. A welded steel ship, for example, may break in two in a fraction of a second, due to a brittle crack which runs around its hull and deck at a speed of up to 2000m sec:' Temperature plays a major part in the effect. Except for face centred cubic metals, virtually all solids become brittle at low temperatures. The transition from ductile behaviour to brittle behaviour generally occurs in a narrow range, a few tens of degrees only, so that it is possible to characterise a material by a certain transition temperature. In mild steel, a crack-arrest temperature commonly occurs in the range -23 to 73C. Below the crack-arrest temperature, the metal will allow a crack, once started, to run as a brittle fracture at a stress of the order 69 MPa, which is in the range of ordinary working stresses for steel in structural engineering. Above this temperature, the metal will stop such a crack by extensive plastic deformation at the tip.

A number of engineering tests have been devised to evaluate the transition from brittle to ductile fractures in steels. One of these is the Charpy impact test with a V notch specimen. Laboratory environment, condition and procedure are set out by AS1544-1975.

Basically, the Charpy specimen has a square cross section (10mm x 10mm) and contains a 45 V notch 2mm deep, with a 0.25mm root radius, as shown in Fig. 1.6a. The specimen is supported

cri,

6 mm t

5.5 cm

Fig. 1.6b. Method of applying the impact load to a Charpy specimen.

The principal measuremennt from the impact test is the energy absorbed in fracturing the specimen. After breaking the test bar, the pendulum rises to a height which decreases as the energy absorbed in fracture increases. The energy absorbed in fracture is read directly from the calibrated dial on the testing machine.

The notch bar impact test is most meaningful when conducted over a range of temperatures. By using the test, a change in the mode of fracture of steel as a function of temperature can be observed.

//i cm

Fig. 1.6a. V-notch Charpy impact test specimen. Fig. 1.6c. Representative Charpy impact ductile to brittle fracture transition.

6/84 S1:Page 4

+100 -120 +20 +60

ROLLING DIRECTION

low -100 -00

ductile

brittle

high

ENER

GY AB

SORB

ED

LONGITUDINAL (L)

TRANSVERSE (T)

Impact test results are dependent on a number of factors besides temperature. Rolling direction of the plate, steel chemistry and microstructure are also impact dependent.

TEMPERATUREC

Fig. 1.6d. Effect of specimen orientation of Charpy transition temperature curves.

6/84 Si: Page 5

SEC HON TWO

HEAT EA I I ENT F STEEL

2.1 introduction

2.2 Annealing

2.3 Normalising

2.4 Hardening by Heat Treatment

2.5 Tempering

2.6 Stress-Relieving

2.7 Definition of phases in steel 2.7,1 Carbides 2.7.2 Austenite 2.7.3 Ferrite 2.7.4 Pearlite 2.715 Martensite

2.8 Alloying Elements 2.8.1 Carbon 2.8.2 Boron 2.8.3 Silicon

"2.8.4 Manganese 2.8.5 Molybdenum 2.8.6 Chromium 2.8.7 Titanium 2.8.9 Sulphur and Phosphorus

6/84 S2: Page 1

2. HEAT TREATMENT OF STEEL

2.1 INTRODUCTION The definition of heat treatment given

in the Metals Handbook is

"a combination of heating and cooling operations, timed and applied to a metal or alloy in the solid state in a way that will produce desired properties".

The mechanical properties of steel are dependent on chemical composition and microstructure. Although chemical composition affects the stability of certain phases in the microstructure, heat treatment generally controls the microstructure in a steel. Thus phases, grain size and distribution can all be influenced and controlled by applying certain heat treatments.

2.2 ANNEALING Annealing is usually carried out at

temperatures above the Ai curve (see Fe-C Phase Diagram). Annealing consists of the slow cooling of a steel to low temperatures. By annealing a steel, the microstructure tends toward that predicted by the phase diagram, equilibrium conditions. The result of annealing is a uniform composition, stress-free microstructure of ferrite and pearlite. The purpose of annealing may be to refine the grain size, induce softness, improve electrical and magnetic properties and, in some cases, to improve machinability.

1500

1400

1300

1200

1100

P to I:C 900 I 4 CC800 to

a.

I 700

600

500

400

300

200

100

...,

., 1111

-,

Austenite ), ,,.. 1

,

1000

x

ANNEALING / Austenite & Cementite

AI /

-,_

-, RECRYSTALLISATION

HIGH TEMPERATURE STRESS RELIEF Ferrite & Cementite

LOW TEMPERATURE STRESS RELIEF

------

1 0 20 3.0 40 50

PERCENTAGE CARBON BY WEIGHT

Fig. 2.1a. The Iron-Carbon Phase Diagram.

6/84

800

EUTECTOID TEMPERATURE

700 AUSTENITE

0.0.*

500

600

PEARUTE

PEARLITE BAINITE

50%

.9 uJ CC

< 400 cc

G. 2 IIJ

300

N BAINITE AUSTENITE

3

200

100 MARTENSITE AND AUSTENITE

104 105 0 0.1 1 10 100 103

TIME, IN SECONDS Fig. 2.4a. Time Temperature Transition Diagram. Lines 1, 2, 3 & 4 show

varying cooling rates to yield the corresponding microstructures.

BAINITE AND MARTENSITE

MARTENSITE-0".2 3 fral 4 FINE PEARLITE

1

M50

6/84 S2: Page 3

TEM

PER

A TU

RE

EFFECT OF BORON FERRITE 'C' CURVE

Fig. 2.4b. Schematic diagram showing the effect of boron on the isothermal transformation diagram of Bisalloy steels.

6/84 S2: Page 4

2.3 NORMALISING Normalising consists of air cooling the

steel from the Al temperature (see Fe-C Phase Diagram) to room temperature. Normalising has a faster. cooling rate than that of annealing. The result of normalising is to obtain a finer pearlite structure which yields increased mechanical properties. Hardness and tensile properties would both be increased. Normalising may also be used to improve machinability, modify and refine cast dendritic structures, refine the grain size and homogenise the microstructure in order to improve the response in mechanical properties.

2.4 HARDENING Microstructure plays a dominant role

in the mechanical properties of steels. By controlling the cooling rate, different microstructures can be obtained, thus different mechanical properties can be produced.

Under slow cooling rates (annealed conditions), an equilibrium structure of pearlite and ferrite is obtained from a low alloy steel, such as from the BISALLOY range. This structure has the lowest hardness.

Under moderate cooling rates (normalising), a finer grained matrix results. Pearlite, ferrite and bainite would all be present. This finer grained structure has a higher hardness, due to the increase in the amount of bainite present.

Under severe cooling rates (quenching), a martensitic microstructure is formed. Martensite is a very hard, brittle metastable phase. A fully martensitic structure is obtained during the production of the BISALLOY range. The formation of martensite leaves high residual stresses in the steel which result in the brittle nature of this phase. By further heat treatment, the brittleness can be removed with only a slight loss of hardness. This is usually done by tempering.

2.5 TEMPERING In the as-quenched martensitic

condition, the steel is too brittle for most applications. The purpose of tempering

is to relieve residual stresses and to improve the ductility and toughness of the steel. This increase in ductility is usually attained at the sacrifice of some hardness or strength.

In general, over the broad range of tempering temperatures, hardness decreases and toughness increases as the tempering temperature is increased.

The tempering range of 300-600C is a dividing line between the applications that require high hardness and those requiring high toughness. If the principal desired property is hardness or wear resistance, the part is tempered below 450C; if the primary requirement is toughness, the part is tempered above 4509C.

2.6 STRESS RELIEVING

This process, sometimes called subcritical annealing, is useful in removing residual stresses due to fabrication or production. Stress in the metal caused from heavy machining or other working processes, can be removed in a less brittle material. Stress relieving is carried out between 450-650C. The higher the temperature, the greater the effect of stress relief.

2.7 DEFINITION OF PHASES IN STEEL

2.7.1 CARBIDES Iron carbides are present in all steels.

One common carbide is cementite (Fe3C). Cementite is a hard brittle interstitial precipitate which increases the hardness of the microstructure.

2.7.2 AUSTENT1TE Au stenite is an interstitial solid

solution of carbon dissolved in faced centred cubic iron. Maximum solubility is two per cent C at 1147C.

Average properties are: Tensile strength Elongation Hardness

It is normally not stable at room temperature.

830 MPa 10 per cent in 50mm

BHN 370 (approx.)

6/84 S2: Page 5

2.7.3 FERRITE Ferrite is an interstitial solid solution of

a small amount of carbon dissolved in body centred cubic iron. The maximum solubility is 0.025 per cent C at 723C and it dissolves only 0.008 per cent at room temperature. Average properties are: Tensile strength 300 MPa Elongation

40 per cent in 50mm Hardness BHN 170 (approx.)

2.7.4 PEARLI1 Pearlite is the eutectoid mixture

containing 0.80 per cent C and is formed at 723C on very slow cooling. It is a very fine platelike or lamellar mixture of ferrite and cementite.

Average properties are: 600 MPa

20 per cent in 50mm BHN 270 (approx.)

2.7.5 MARTENSITE The martensitic structure in steels is a

simple phase which marks it from the aggregates of ferrite and carbides. The martensitic crystal structure is body centred tetragonal and can be treated as an intermediate structure between phases. The phase change which occurs in a martensitic transformation is brought about by the movement of the interface of parent and product phases. Martensite is a very hard brittle phase, which produces shape deformation and high internal stresses on formation.

2.8 ALLOYING ELEMENTS

Most alloying elements in steels tend to increase the resistance of the steel to softening when it is heated, which means that for a given time and temperature of tempering, an alloy steel will possess a greater hardness after tempering than a plain carbon steel of the same carbon content.

2.8.1 CARBON Carbon is the foremost alloy element of

steel and it has the farthest reaching influence on it. The hardenability of a steel is strongly influenced by its carbon content. As the carbon content rises, the

mechanical strength and the hardening properties of the steel improve, but its elasticity, forging, welding and cutting properties suffer. The carbon content has no influence on the corrosion resistance of the steel.

In addition to carbon, every unalloyed steel contains silicon, manganese, phosphorus and sulphur, which are introduced during manufacture. The addition of further alloy elements to produce specific desired effects and the intentional increase of the contents of manganese and silicon give rise to alloy steel.

2.8.2 BORON Boron is unique among the alloying

elements in that its effect on hardenability is large and the optimum concentration for this effect is small (0.0007%). Reproducibility of this concentration uniformly is so difficult that steelmakers usually aim at the lower hardenability obtained between 0.0015 and 0.0025% boron. In this region, hardenability is less sensitive to concentration. The hardenability of boron-treated steels is attributed to the role boron plays on the pearlite transformation. Boron inhibits the nucleation of pearlite at the grain boundaries. This effect can be seen on the TTT diagram Fig. 2.4b. The effect of adding small amounts of boron is comparable to high alloy steel additions without the drawbacks of availability and price of traditional alloy additions such as molybedenum or chromium. Boron improves the deep hardening of constructional steels.

2.8.3 SILICON Silicon is present in all steels. It has

similar effects to that of carbon, increases hardness (to a lesser degree), however does not promote the welding problems which carbon exhibits.

2.8.4 MANGANESE Manganese improves the strength

and toughness properties of the steel. Furthermore, manganese has a favourable influence on the forging and welding properties.

2.8.5 MOLYBDEMUM Molybdenum improves the tensile

properties of the steel. Improvement in heat resistance is also noted with that corresponding improvement in weldability. Molybdenum has a strong tendency to form carbides and is the alloy element of choice in heat-treating steels as well as heat-resistant steels.

Tensile strength Elongaton Hardness

6/84 S2: Page 6

2.8.6 CHROMIUM Increases in hardness and strength are

notable features when chromium is added to low alloy steels. It also improves the heat resistance and non-scaling properties of the steel.

2.8.7 TITANIUM The formation of titanium carbide

greatly improves the hardness of the steel. Titanium also reduces the grain size, with the corresponding improve-ment in mechanical properties. It is also used to facilitate uniform and predictable distribution of boron in boron-containing steels.

2.8.8 SULPHUR AND PHOSPHORUS Both elements are kept to a minimum

and are treated as impurities. In particular, low sulphur contents can lead to enhanced ductility properties ( eg elongation, reduction in area and impact properties). It is desirable to keep phosphorus contents low to avoid temper embrittlement during heat treatment.

6/84 S2: Page 7

SECTION THREE

SPECIFICATION OF BISALLOY STEELS 3.1 Production of Quenched & Tempered

Steel Plate 3.1.1 Production Process 3.1.2 Metallurgical Grades of Bisalloy

Products

3.2 Bisalloy 80 3.2.1 Chemical Composition 3.2.2 Tensile Properties 3.2.3 Impact & Hardness Properties 3.2.4 Fatigue Properties

3.3 Bisalloy 80 PV 3.3.1 Introduction 3.3.2 Chemical Composition 3.3.3 Tensile Properties 3.3.4 Impact & Hardness Properties

3.4 Bisalloy 320 & Bisalloy 360 3.4.1 Chemical Composition 3.4.2 Tensile Properties 3.4.3 Impact & Hardness Properties 3.4.4 Fatigue Properties

3.5 Bisalloy 500 3.5.1 Chemical Composition 3.5.2 Tensile Properties 3.5.3 Impact & Hardness Properties

3.6 Chromium Molybdenum Steels 3.6.1 Chromium Molybedenum Alloy

Grades 3.6.2 Chemical Composition 3.6.3 Tensile Properties 3.6.4 Size & Order Quantities

3.7 HY80 and HY100 3.7.1 Introduction 3.7.2 Chemical Composition 3.7.3 Tensile Properties 3.7.4 Impact Properties

3.8 Special Requirements 3.8.1 Customer Orders 3.8.2 Special Applications of Bisalloy

500 3.8.3 520 MPa Quenched & Tempered

Steel 3.8.4 Bisalloy with BHN 400

6/84 53: Page 1

3. SPECIFICATIONS OF BISALLOY STEELS

3.1 PRODUCTION OF QUENCHED AND TEMPERED STEELS

Bunge Industrial Steels Pty Limited is the sole Australian tonnage producer of quenched and tempered steel plate. 3.1.1 PRODUCTION PROCESS

Feed plates for the BIS heat treatment plant are supplied by Broken Hill Proprietary Company in the form of hot-rolled plates from Australian Iron and Steel Pty Ltd at Port Kembla.

The production of feed for any successful quenching and tempering operation demands the highest technical expertise of the steelmaker as well as the heat treater. In particular, the steel grades involve special steelmaking techniques and plate manufacturing procedures. These have been developed at AWLS, Port Kembla, and incorporated into the total production process. In addition, quality control and assurance of the entire process is maintained through regular, planned liasion between technical and production personnel from both Al&S and BIS.

The heat treatment operation, shown schematically below, consists of heating the steel plate in the austenitising furnace to approximately 900C, holding at that temperature for a predetermined time dependent on plate thickness and quenching by water at a sufficiently rapid rate to produce an essentially fully martensitic microstructure. In the BIS plant, quenching water is delivered through high intensity curtain headers and spray pipes at a rate of up to 123,500 litres per minute while the plate is guided between two sets of rolls of the continuous roller quench unit.

Quenching is followed by tempering at a temperature chosen to produce the desired combination of strength, hardness and toughness. For example, the highest hardness wear resistant grades are tempered at a temperature between 175C and 450C, depending on the hardness range specified, while the high strength structural grades furnished to guaranteed tensile and

impact properties, such as Bisalloy 80, are tempered at 600-615C.

The versatility of the heat treatment plant permits BIS not only to produce standard high strength and wear resistant grades, but also to quench and temper custom-made grades of steel plates.

Enquiries for such grades should be directed to BIS, Unanderra.

Note that steels sold in the quenched and tempered condition are normally intended to be used as supplied. However, there may be occasions when parts, such as heads for pressure vessels, require to be hot formed. Because of the significant influence of re-heat temperature on the mechanical properties of quenched and tempered steels, it is desirable that in such cases, specific information as to the correct heat treatment should be obtained for the particular steel in question.

Maximum advantage has been taken of the highly efficient quench operation by reducing the alloy content substantially. The strict control of operating conditions for producing a high strength product is maintained by the production process. The result is a weldable, workable, high strength steel product.

6/s4 S3: Page 2

3.1.2 METALLURGICAL GRADES OF BISALLOY Bunge Industrial Steels is at present

producing the following grades of steel plates:

METALLURGICAL ABBREVIATION APPLICATION GRADE

BISALLOY 80 PV

BISALLOY 80 HIGH STRENGTH STEEL MEETING MECHANICAL PROPERTIES OF ASTM A514 HIGH STRENGTH STEEL MEETING PRESSURE VESSEL SPECIFICATION ASTM A517

BIS-80

BIS-80PV

BISALLOY 320 BIS-320 BHN 320 WEAR RESISTANT

STEEL PLATE

BISALLOY 360 BIS-360 BHN 360 WEAR RESISTANT STEEL PLATE

BISALLOY 500 BIS-500 BHN 500 WEAR RESISTANT

STEEL PLATE

CHROMIUM MOLYBDENUM Cr/Mo HIGH TEMPERATURE CREEP STEEL RESISTANT STEEL MEETING

ASTM A387

PLATE MEETING DEFENCE SPECIFICATION MIL-S-16216J

HY80/HY100 HIGH STRENGTH STEEL HY80/1-1Y100

PRODUCTION PROCESS AT BUNGE INDUSTRIAL STEELS UNANDERRA As rolled plate to BIS specifications

from AI&S Port Kembla Plate Inspection at Unanderra

by Quality Assurance Metallurgist

Charging Table Hardening Furnace

Continuous Quenching Unit Tempering Fuinace

Cooling Table

PRODUCTION

On line plate hardness testing Plate Inspection (shape/surface)

Testpiece Sampling

ON LINE

QUALITY

ASSURANCE

Mechanical Testing Laboratory Approval

Certification

NATA PROGRAM APPROVED

LABORATORY

Despatch

6/84 S3: Page 3

3.2 BISALLOY 80

3.2.1. CHEMICAL COMPOSITION Chemical composition data for BIS-80

is shown below. Those elements not shown are present in residual quantities only. The table indicates the very close control achieved during steelmaking over the concentration of individual elements. The carbon equivalent is kept to a minimum by a low alloy content. The tight carbon equivalent range, such as that possessed by all the Bisalloy range of steels, contributes to uniformity of mechanical properties as well as consistency in welding. The ease of other fabrication operations, such as bending and forming, is improved by the low non-metallic content resulting from the low sulphur and phosphorus content of these steels. Carbon Equivalent =

Mn Cr + Mo + V Ni + Cu C+ +

6 5 15 For BIS-80, a typical value of C.E. of 0.53

would be expected.

CHEMICAL COMPOSITION OF BISALLOY 80

Element Range %

Typical %

Carbon 0.15 0.21 0.17 Manganese 0.80 1.30 1.15 Silicon 0.15 0.50 0.40 Molybdenum 0.40 max. * Chromium 0.60 1.20 0.85 Boron 0.0005 0.006 0.002 Titanium 0.015 0.050 0.030 Nickel 0.30 max 0.020 Copper 0.20 max 0.020 Sulphur 0.015 max 0.010 Phosphorus 0.025 max 0.020

*Molybdenum content is dependent on the thick-ness of the plate. All data is given as a weight per cent.

3.2.2 TENSILE PROPERTIES It is important to recognise that tensile

properties are dimensionally sensitive, thus the thickness of the plate affects the tensile properties. The guaranteed tensile properties of BIS-80 are:

BIS-80

Property Thickness mm

Minimum Value MPa

Yield Strength 3.25 55 690 60 100 620

Tensile 3.25 55 790 Strength 60 100 720 Elongation 3.25 65 16%

70 100 14%

Reduction 3.25 16 35% in Area 20 100 45%

6/84 S3: Page 4

PLATE THICKNESS 5 TO 12 mm

YIELD STRENGTH TENSILE STRENGTH

30

25

20

15

FRE Q

UEN

CY

%

FREQ

UENC

Y %

10

5

660 800 780 760 720 740 700

MPa

ELONGATION REDUCTION IN AREA

30

25

20

15

FREQ

UEN

CY

%

FREQ

UEN

CY

%

10

5

18 20 22 24 26 28 30 30 35 40 45 50 55 60 65

6/84 S3: Page 5

30

25

FREQ

UEN

CY %

5

PLATE THICKNESS 12 TO 25 mm

TENSILE STRENGTH YIELD STRENGTH

680 700 720 740 760 780 800

780 800 820 840

MPa.

REDUCTION IN AREA ELONGATION

30

25

20

- 10 0

20 22 24 26 28 30 32 35 40 45 50 55 60 6

Ok

6/84 S3: Page 6

680 700 720 740 760 780 800

25

20

FREQ

UEN

CY %

MPa

25

20 a >-LI z iu 15 D 0 Lu cc u. 10

PLATE THICKNESS 25 TO 50 mm

YIELD STRENGTH

25

20

15

10

TENSILE STRENGTH

780 800 820 840 860

MPa

880

900 FR

EQUE

NCY

%

ELONGATION REDUCTION IN AREA

16 18 20 22

%

24 26 28 40 45 50 55 60 65

6/84 S3: Page 8

16 18 20 22 24 26 28 35 40 45 50 55 60 65

0/0

6/84 53: Page 7

PLATE THICKNESS 50 TO 100 mm.

740 780 760 800 720 680 700

YIELD STRENGTH 25

20

MPa

TENSILE STRENGTH

25

820 780 840 800 860 880

>- 20

O 15 CC LL

10

MPa

ELONGATION

FREQ

UENC

Y %

25

20

15

10

REDUCTION IN AREA

1000

800

STRE

SS (M

Pa)

600

400

200

30

20

ELON

GATI

ON (%

)

10

80

60

REDU

CTIO

N OF

ARE

A (

)

40

20

TYPICAL TENSILE PROPERTIES FOR BIS-80 Specimen 1 Thickness

mm Yield

Strength MPa

TS2 MPa

Elongation %

Reduction in Area

% A 6 720 800 24 35 B 12 760 835 24 40 C 20 780 890 24 50 D 50 750 840 20 60 E 75 740 830 19 65

1. These are actual specimens tested during the routine quality assurance programme.

2. Tensile Strength

The tensile test data for various plate of BIS-80 shown in the graphs clearly indicates that the tensile requirements of such standards as ASTM A514 & A517 can be readily satisfied by the standard grade BIS-80. The graphs also display the variation in tensile properties which may occur. At BIS, the technical staff guarantee a minimum value, however, higher values are always obtained.

High Temperature Tensile Data

The application of quench and tempered steel plate such as BIS-80 at elevated temperatures should be approached with caution. Prolonged exposure to excessive heat will lead to substantial loss of mechanical properties, including strength and hardness. This is primarily due to a micro structural change of the plate due to over-tempering.

Any proposal for the use of Bisalloy 80 at temperatures above 150C should be referred to the manufacturer. The following graphs show the results of high temperature tests performed on BIS-80 in accordance with AS2291-1979. A clear indication of the likely effects of high temperatures on the mechanical properties of BIS-80 is given.

BIS-80 HIGH TEMPERATURE TENSILE DATA

Y 1, 41' : 11' TENSILE STRENGTH

O '''

Qx...,,,.._..._, a 8

o :

x 16,

x

. ,x

1.---, x AN

PROOF 0.2%

STRESS \ 4

\ x

a

100 200 300 400 500 600 TEST TEMPERATURE (CC)

MALLOY 80 12 mm PLATE 20 mm PLATE X 50 mm PLATE a

-----4 a a ox x

x o --o

x a

x--*"x

' ,

--

....i

--- x ____

. . x

.

' 4 - . . . . . . _.2. .

q . . . . _ 6 x gx = .

.

_ :

100 200 390 400 500 600 TEST TEMPERATURE (DC)

6/84 S3: Page 9

3.2.3 IMPACT & HARDNESS PROPERTIES

Impact and hardness properties of BIS-80 are given below. The notch toughness of BIS-80 steel plates is extremely good. Notch toughness of these plates has been obtained by careful control over chemical composition and heat treatment process. As shown in the graphs, the Charpy V-notch energy values obtained during the routine impact tests at -20C easily exceed the nominated minimum values and, further, extend to exceptionally high energies.

Plates of BIS-80 have exceptional notch toughness at low temperatures, as demonstrated by the impact transition curves for tests in both the longitudinal and transverse directions, Fig. 3.2a.

The normal measure of notch toughness of quenched and tempered

steels for pressure vessel and similar applications is the lateral expansion of the broken Charpy test piece. The criterion adopted is that the lateral expansion should exceed 0.38mm at the test temperature. Tests have indicated that BIS-80 consistently meet the requirement at temperatures of -20C and below.

It is normal practice to Brinell hardness test every plate produced as a matter of routine quality assurance. The range from BHN 235-293 is guaranteed. Unless otherwise specified, one tensile test and one set of three Charpy V-notch tests are taken from each ten tonnes of each batch of plates and the tested plate is certified as having mechanical properties meeting the certification.

* A batch is a group of plates of the same thickness and from the same heat.

MINIMUM CHARPY TEST RESULTS FOR BIS-80

Plate

mm

Test Piece

mm

Charpy Impact Value at -20C Joules

average of 3 individual

3.25 5 10 x plate thickness 10 7 6 8 10 x 5 13 10

10 10 x 7.5 20 15 ?1.2 10 x 10 27 20

6/84 S3: Page 10

emm Plate Temperature -20C Specimen Size 10 x 5 mm. 30

26

22

18

15

12

10

8

6

4

2

FRE

QUEN

CY 4'/0

6 10 x 5

12

120

EN

ERG

Y V

ALU

E (J

OU

LES)

100 -

80 -

60

40 -

20 -

Plate thickness Test Piece Size Longitudinal Transverse (mm) (mm) (mm) (mm)

Plate thickness Test Piece Size Longitudinal Transverse

10x10

10 x 10 ---

-

-80 -60 -40 -20 0 +20 -80 -60 -40 -20 0 +20

TEST TEMPERATURE(C) TEST TEMPERATURE (C)

Figure 3.2a Transition Impact Diagram for BIS-80

CHARPY IMPACT NOTCH TOUGHNESS VALUES BISALLOY 80

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110

ABSORBED ENERGY - JOULES

6/84 S3: Page 11

25

50

180

160 U) w

140 0

w 120

>

cc tu w

100

80

60

40

20

6/84 53: Page 12

CHARPY IMPACT NOTCH TOUGHNESS VALUES BISALLOY 80 12 mm Plate Temperature -20C Specimen Size 10 x 10 mm.

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110

ABSORBED ENERGY-JOULES

DISTRIBUTION DIAGRAM OF CHARPY V NOTCH VALUES FOR BISALLOY 80 25 mm Plate Temperature - 20C Specimen Size 10 x 10 mm.

12

10

>- 0 9

0 8 CC u- 7

6

5

4

3

2

1

20 25 30 35 40 45 50 65 70 75 80 85 90 95 100 105 110 115 120 125 130

ABSORBED ENERGY-JOULES

FR

EQ

UE

NC

Y%

14

10' le 2 X 10' 10'

SN CURVE BISALLOY 80 PARALLEL TO RD

G2 R = -a 800

600

400

200

AL

TE

RN

AT

ING

STR

ES

S M

Pa

800

600

400

200

0 0 -400

UTS

GOODMAN DIAGRAM ENDURANCE CURVES FOR BISALLOY 80

2. 10 CYCLES FATIGUE STRENGTH R =-1

400 200 800 -200 600

3.2.4 FATIGUE PROPERTIES A metal subjected to a repetitive or

fluctuating stress will fail at a stress much lower than that required to cause fracture on a single application of load. Failures occurring under conditions of dynamic loading are called fatigue failures. Fatigue has become progres-sively more prevalent as technology has developed equipment subject to repeated loading and vibration.

There are many factors which influence fatigue failures. The most important are maximum tensile stress, variation in applied stress and number of cycles of applied stress. Variables such as stress concentration, temperature, corrosion and others also influence fatigue failures.

Fatigue Results on BIS-80 Fatigue tests were conducted on BIS-80

by Unisearch Ltd, the research division of the University of New South Wales.

BIS-80 test pieces oriented parallel to the rolling direction exhibited the highest fatigue limit of 420 MPa, while the transversely oriented test pieces had a fatigue limit of 400 MPa. The fatigue limit for as welded 12mm BIS-80 plate test pieces is 160 MPa. In the case of welded plates with weld reinforcement, fatigue failure invariably initiated at the toe of the reinforcement and propogated through the parent metal. The tests indicated that, if excessive reinforcement is removed from a welded joint, its fatigue limit will approach that of the parent plate. The fatigue tests were conducted up to a run-out condition of 2 x 106

cycles.

NUMBER OF CYCLES

STRESS AMIN MPa

6/84 S3: Page 13

Hardness BHN Lateral expansion at -20C

235 to 293 0.25mm Minimum

0.38mm Average

3.3 BISALLOY 80 PV 3.3.1 INTRODUCTION

Bisalloy 80 PV is a high strength quenched and tempered low alloy steel plate for pressure vessel applications. Bisalloy 80 PV is intended for use in pressure vessels and every plate is mechanically tested in line with the provisions of ASTM A517. The only difference between Bisalloy 80 and the pressure vessel version is the frequency of mechanical tests conducted on the steel plate. It is therefore possible to convert Bisalloy 80 into Bisalloy 80 PV, provided the appropriate testing is carried out.

Upon request, a formal specification approved by the relevant statutory authority in an Australian Standard format is available. Direct contact with BIS at Unanderra is necessary.

3.3.2 CHEMICAL COMPOSITION The chemical composition of this

material is the same as Bisalloy 80. (See Section 3.21)

3.3.3 TENSILE PROPERTIES Every plate designated Bisalloy 80 PV is

individually tested. One test specimen for tensile testing is taken from each end of the plate, midway between centre and either edge. Tensile tests will be conducted in accordance with AS1391 to establish the tensile properties.

3.3.4 IMPACT AND HARDNESS PROPERTIES

Three Charpy V-notch test pieces are cut from each test specimen parallel to the principal direction of rolling, with the axis of the notch perpendicular to the rolled surface of the plate. Each test piece is tested in accordance with AS1544, Part 2. The test temperature will be -20C, unless otherwise agreed upon between the manufacturer and the purchaser.

Lateral expansion measurements will also be conducted in accordance with ASTM A517. An average value for lateral expansion tests will not be below 0.38mm.

IMPACT & HARDNESS VALUES FOR BIS-80 PV

BIS-SO PV Thickness Yield

Strength Tensile Strength

Elongation Reduction in Area

mm MPa MPa % % 3.25 16 690 790 16 35

16 65 690 790 16 45 65 100 620 720 14 45

These are minimum requirements for the tensile properties of Bisalloy 80 PV.

6/84 S3: Page 14

3.4 BISALLOY 320 AND 360

3.4.1 CHEMICAL COMPOSITION Both BIS-320 and BIS-360 have the same

chemical composition. The higher hardness of BIS-360 is obtained during the heat treatment of these steels. The chemical composition data is shown below. Those elements not shown are present in residual quantities only.

A typical carbon equivalent of these grades would be C.E. = 0.53.

The tight carbon equivalent range contributes to uniformity of mechanical properties, as well as consistency in welding.

3.4.2 TENSILE PROPERTIES Unless dictated by special customer

requirements, the abrasion resistant grades are seldom tensile tested. In general however, as the hardness and therefore strength of the grades increase, the ductility in terms of elongation and reduction in area decreases. The higher hardness grades are also characterised by a higher yield to tensile strength ratio than that of BIS-80, approaching 0.97 for a typical BIS-360 plate.

CHEMICAL COMPOSITION OF BIS-320 & BIS-360

Element Range %

Typical %

Carbon 0.15 0.21 0.17 Manganese 0.80 1.30 1.15 Silicon 0.15 0.50 0.40 Molybdenum 0.40 max * Chromium 0.60 1.20 0.85 Boron 0.0005 0.006 0.002 Titanium 0.015 0.050 0.030 Nickel 0.30 max 0.020 Copper 0.20 max 0.020 Sulphur 0.015 max 0.010 Phosphorus 0.025 max 0.020

*Molybdenum content is dependent on the thickness of the plate. All data is given as a weight per cent.

TYPICAL TENSILE PROPERTIES FOR BIS-320 & BIS-360

PROPERTY BIS-320 BIS-360

Yield Strength

140,000 psi 98kg/mm2

965 MPa

165,000 psi 116kg/mm2 1,135 MPa

Tensile Strength

155,000 psi. 109kg/mm2 1,070 MPa

180,000 psi 126kg/mm2 1,240 MPa

Elongation in 50mm 13% 11%

Reduction in Area 40 35

It is important to recognise that mechanical properties of Bisalloy products are dimensionally sensitive. Thus, thick plates will have slightly lower tensile properties to that of a thin plate. Also, no two chemical compositions, rolling conditions or heat treatments are identical. Therefore, no two plates will be identical. All plates produced at BIS fall within a small range, however there is a distribution in the mechanical properties of the plates, ie not all BIS-360 has a hardness of exactly BHN 360 (nominally BHN 360-400).

HIGH TEMPERATURE TENSILE DATA The use of any of the wear resistant

grades at elevated temperatures should be avoided at all times. Prolonged exposure to excessive heat will lead to a substantial loss of strength and hardness due to the microstructural changes caused from over-tempering. Softening becomes particularly significant as the operating temperature approaches the tempering temperatures of the steel.

Any proposed usage of BIS-320 or BIS-360 at temperatures above 100C should be referred to the manufacturer.

The following graphs describe the mechanical behaviour of BIS-360 at elevated temperatures. The tests were conducted in accordance with AS2291-1979.

6/84 S3: Page 15

100 200 300 409 500 600

ELO

NG

ATI

ON

(%)

30

20

10

RE

DU

CTIO

N O

F A

REA

( %)

80

60

40

20

TEST TEMPERATURE (C)

Plate Thickness mm

Hardness BHN

Charpy Impact Values at +20C in Joules

6 320 360 12

320 360 25 320 360 50 320 360 80 320 360

30 45 40 35 30

m 0.

U)

cc

HIGH TEMPERATURE TENSILE DATA FOR BISALLOY 360

Yll,...

BISALLOY 20 mm

360 PLATE

200 Agamih.

TENSI E STRENGTH

000

PROOF 0.2%

800 STRESS

600

400

200

100 200 300 400 500

600

TEST TEMPERATURE (C)

TYPICAL IMPACT AND HARDNESS VALUES FOR BIS-320

TYPICAL IMPACT AND HARDNESS VALUES FOR BIS-360

Plate Thickness mm

Hardness BHN

Charpy Impact Values Joules

+20C 0C -20C

6 360 400 25 20 15 12 360 400 35 25 20 25 360 400 30 20 15 50 360 400 25 20 80 360 400 20 15

3.4.3 IMPACT AND HARDNESS PROPERTIES

The impact and hardness values are given below. As the hardness value increases, the impact value decreases. Thus, as a steel becomes harder, it also displays a more brittle nature. The wear resistant grades of steel plate are graded by their hardness value, which is an indication of their wear resistance.

3.4.4 FATIGUE PROPERTIES Fatigue tests on BIS-320 have been

conducted by the research division of the University of New South Wales. It was found that the fatigue limit of BIS-320 is 390 MPa. The test pieces were axially ground in the longitudinal direction and oriented parallel to the rolling direction. Tests were conducted up to the run-out condition of 2 x 106 cycles. This value may be compared with a fatigue limit of 420 MPa for BIS-80. S-N curves and endurance curves are included.

6/84 S3: Page 16

1

GOODMAN DIAGRAM BISALLOY 320 2 x 105 CYCLES

1100

1000

900

-A

LTE

RN

ATI

NG

STR

ESS

IN M

PA

800

700

600

500

1200

800

0

0. 2

2

400

400 0 400

Smay MPa

800 1200

400

S N CURVE BISALLOY 320

DNF

104

105

106 2 x106 107 NUMBER OF CYCLES

6/84 S3: Page 17

Hardness BHN 460 min. to 525 max.

Fracture Toughness by Charpy Impact Test at +20C using 10 x 10 specimen 20 Joules

3.5 BISALLOY 500 3.5.1 CHEMICAL COMPOSITION

Chemical composition data for BIS-500 is shown below. Those elements not shown are present in residual quantites only. To obtain a higher hardness for this grade, the carbon content has been increased. To ensure the correct chemistry balance, the alloy content levels of silicon and chromium have also been increased.

A typical carbon equivalent value of BIS-500 would be C.E. = 0.64.

CHEMICAL COMPOSITION OF BIS-500

Element Range %

Typical %

Carbon 0.26 0.32 0.27 Manganese 0.90 1.30 1.15 Silicon 0.40 0.90 0.60 Molybdenum 0.20 0.30 0.25 Chromium 0.70 1.10 0.90 Boron 0.0005 0.006 0.002 Titanium 0.015 0.050 0.030 Nickel 0.35 max 0.020 Copper 0.35 max 0.020 Sulphur 0.020 max 0.010 Phosphorus 0.025 max 0.020

3.5.2 TENSILE PROPERTIES Unless specifically required by the

customer, the abrasion resistant grades are seldom tensile tested. However, if required by the customer, all tests can be conducted. Tensile properties of BIS-500 are given below.

BIS-500 TYPICAL TENSILE PROPERTIES

Yield Strength 215 000 psi 150 kg/mm2 1 480 MPa

Tensile Strength 230 000 psi 160kg/mm2 1 585 MPa

Elongation 8% Reduction in Area 30% Yield: TS ratio 0.94

3.5.3 IMPACT AND HARDNESS PROPERTIES

BIS-500 is the hardest grade produced at Unanderra. Impact and hardness values are given below. As with all wear resistant grades, the hardness value grades the material.

IMPACT AND HARDNESS VALUES FOR BIS-500

cii Guaranteed

6/84 S3: Page 18

0.50 0.50 0.50 1.00 1.00

0.50 1.00 1.25 2.25 3.00

2 12 11 22 21

Nominal Chromium Content

Nominal Molybdenum Content

Grade

3.6 CHROMIUM MOLYBDENUM STEELS

3.6.1 CHROMIUM MOLYBDENUM ALLOY GRADES

BIS is also producing a chromium molybdenum steel plate in accordance with the requirements of ASTM A387. The material is used primarily for elevated temperature service, with application in boiler installations, pressure vessel installations, pipework systems and pipe support installations.

Through close-co-operation with AI&S producing the steel chemistry require-ments, followed by heat treatment at BIS, the following grades are being produced.

CHROMIUM MOLYBDENUM ALLOY GRADES ASTM A387

NB: British Standards can also be supplied.

3.6.2 CHEMICAL COMPOSITION The chromium molybdenum alloy

grades are based on their chromium and molybdenum content. A more compre-hensive range of chemical composition is given as follows:

CHROMIUM MOLYBDENUM ALLOY GRADES Element 2 11 12 21 22 Carbon 0.21 0.17 0.17 0.15 0.15 Manganese .50 - .88 0.35 - 0.73 0.35 - 0.73 0.25 - 0.66 0.25 - 0.66 Phosphorus 0.035 0.035 0.035 0.035 0.035 Sulphur 0.040 0.040 0.040 0.035 0.040 Silicon 0.13 - 0.45 0.44 - 0.86 0.13 - 0.45 0.50 0.50 Chromium 0.46 - 0.85 0.94 - 1.56 0.74 - 1.21 2.63 - 3.37 1.88 - 2.62 Molybdenum 0.40 - 0.65 0.40 - 0.70 0.40 - 0.65 0.85 - 1.15 0.85 - 1.15

6/84 93: Page 19

A typical chemical analysis of a Cr-Mo steel Grade 22, Class 2, would be as follows:

Element

Carbon 0.125 Phosphorus 0.024 Manganese 0.50 Silicon 0.40 Sulphur 0.009 Nickel 0.060 Chromium 2.25 Molybdenum 1.00 Copper 0.025 Aluminium 0.040 The low non-metallic inclusion content of these steels, as seen by the low sulphur content, con-tributes to the good mechanical properties exhib-ited in tensile and impact tests.

3.6.3 TENSILE PROPERTIES Tensile properties for the Cr-Mo

grades are given below. Tensile strengths, yield strengths and elongation for both classes are displayed. It is important to recognise that Cr-Mo steels are a high temperature steel and will retain high strength up to 600C.

Grade 2 11 12 21 22

iTS in MPa Class 1 380 520 415 585 380 550 415 585 415 585 Class 2 485 620 515 690 450 585 515 690 515 690

2 YS in MPa Class 1 220 240 220 200 200 Class 2 310 310 275 310 310

Elongation in % Class 1 22 22 22 18 22 Class 2 22 22 22 18 22

1 Tensile Strength 2 Yield Strength

NOTE: These are tensile property ranges as detailed by ASTM A387

Typical tensile properties of A387, Grade 22, Class 2, are as follows:

Property Typical Value*

Yield Strength (0.2% Proof Strength) 460 MPa Strength Tensile 620 MPa Elongation 40% Reduction in Area 67%

*Mechanical properties of these grades are dimensionally sensitive. Thus thick plates would have slightly different values.

The standard, ASTM A387, specifies minimum tensile properties for these steels, for each particular grade. Due to the low impurity content of these steels, the tensile properties easily exceed the minimum requirement. The yield strength and tensile strength are on the high end of the range and the minimum elongation is readily achieved.

3.6.4 SIZES AND ORDER QUANTITIES

At the present time, these grades are offered on direct ex-mill basis and so all listed preferred plate from AIS is available, in accordance with minimum order quantities. BIS experience has proven that the most common sizes required are: Width 2500mm Length 6000mm Thickness 16, 20, 25, 40, 50mm

These grades are available from the mill, based on the product of an electric furnace heat being 30 tonnes or multiples of 30 tonnes and made up of 5 tonnes per each individual size (minimum).

6/84 S3: Page 20

3.7 HY-8o AND HY-100 3.7.1 INTRODUCTION

HY-80 and HY-100 are both a military specification. HY-80 and HY-100 are sheared or gas cut alloy steel plates, intended primarily for use in hulls of combatant ships and for other critical structural applications where a notch-toughness, high-strength material is required. The requirements for HY-80 plate apply up to 200mm (8 inches) thick and for HY-100 plate up to 150mm (6 inches) thick.

These steels are covered by military specification MIL-S-16216J (SH).

3.7.2 CHEMICAL COMPOSITION The chemical composition ranges as

specified by the military specifications are as follows:

CHEMICAL COMPOSITION RANGE FOR HY-80 AND HY-100

< 32mm > 32mm

Element HY-80 HY-100 HY-80 HY-100

Carbon 0.10 - 0.20 0.10 - 0.22 0.10 - 0.20 0.10 - 0.22 Manganese 0.10 - 0.45 0.10 - 0.45 0.10 - 0.45 0.10 - 0.45 Phosphorus 0.020 max 0.020 max 0.020 max 0.020 max Sulphur 0.020 max 0.020 max 0.020 max 0.020 max Silicon 0.12 - 0.38 0.12 - 0.38 0.12 - 0.38 0.12 - 0.38 Nickel 1.93 - 3.32 2.18 - 3.57 2.43 - 3.32 2.67 - 3.57 Chromium 0.94 - 1.86 0.94 - 1.86 1.29 - 1.86 1.29 - 1.86 Molybdenum 0.17 - 0.63 0.17 - 0.63 0.27 - 0.63 0.27 - 0.63 Vanadium 0.03 max 0.03 max 0.03 max 0.03 max Titanium 0.02 max 0.02 max 0.02 max 0.02 max Copper 0.25 max 0.25 max 0.25 max 0.25 max Arsenic 0.025 max 0.025 max 0.025 max 0.025 max Tin 0.030 max 0.030 max 0.030 max 0.030 max Antimony 0.025 max 0.025 max 0.025 max 0.025 max 1. All data is given as a weight per cent. 2. As from Military Specification MIL-S-16216J (SH) 3. Product Analysis

6/84 S3: Page 21

3.7.3 TENSILE PROPERTIES

The table below gives the tensile properties by the military specification.

TENSILE PROPERTIES OF HY-80 AND HY-100

Property < 20mm thick HY-80 HY-100

> 20mm thick HY-80 HY-100

Yield Strength MPa 550 690 690 830 550 685 690 795 Elongation % (minimum) 19 17 20 18 Reduction in Area % (minimum) 50 45

TYPICAL TENSILE PROPERTIES OF HY804

Specimen' Thickness1

mm

YS2

MPa

TS3

MPa

Elongation

%

Reduction in Area

% A 9.5 630 750 38 65 B 15.9 605 725 40 65 C 50.8 650 780 25 70

These are actual test results from routine quality assurance program 2 Yield Strength 3 Tensile Strength 4 Test carried out under Section 3.94

3.7.4 IMPACT PROPERTIES

Impact Requirements for a Transverse Charpy Test*

Plate Specimen Average Value of Test Thickness Size Three Tests Temperature

mm mm Joules C

HY-80 HY-100

> 12.7 10 x 10 47 40 -85 81 74 -20

*As from Military Specification MILS-16216J (S}1)

The following values obtained by HY-80 produced at BIS.

TYPICAL IMPACT PROPERTIES OF,HY-80

Specimens Thickness Charpy Impact Values at 85C Joules

mm Longitudinal Transverse

A 9.5 160 B 15.9 130 C 50.8 150 120

1 These are actual specimens tested during the routine quality assurance program.

6/84 S3: Page 22

Thickness of Plate

mm

Actual Hardness

BHN

Classification* Class

477 G2 and SO

477 G2 and SO 477

6 8

10

3.8 SPECIAL REQUIREMENTS

3.8.1 CUSTOMER ORDERS Whilst the standard grades shown

herein are in regular production, it should be known that Bunge Industrial Steels are producing many other grades of heat-treated high strength and abrasion-resistant steels to meet customers' specific requirements. Thus if an abrasion-resistant grade with a hardness value of BHN 420 is for example, required, BIS can produce a special steel for the particular customer. Enquiries for grades other than those shown will be welcomed by Bunge Industrial Steels. 3.8.2 SPECIAL APPLICATIONS OF

BISALLOY 500 BIS-500 is the hardest of the wear

resistant plate produced at Unanderra. Besides applying this steel to wear resistance applications. BIS-500 has been tested as a bullet resistant material. Security applications, such as screens can now be produced from a Bisalloy at only a fraction of the weight of a mild steel alternative.

Ballistic laboratory tests were conducted on BIS-500 by Olin Australia Limited, Winchester Division. Tests were in accordance with AS2343: Part 2 1984 Bullet Resistant Panels for Interior Use. This standard set out a procedure and equipment for testing bullet resistant materials.

BISALLOY 500

*Classification from AS2343 Using a 6mm Bisalloy 500 wear

resistant plate, a classification class of G2 and SO were achieved. Class G2 is the highest requirement in the "G" category (hand guns). Class G2 signifies that the material tested was resistant to attack by a 44 magnum hand gun. Class SO signifies that the material tested was resistant to attack by a 12 gauge shotgun (full choke) firing shot.

Using a 10mm plate, a classification class of R1 was obtained, proving that this material is resistant to attack by a 5.56mm rifle. A panel complying with the

requirements of Class RI will also comply with the requirements of the "G" category.

3.8.3 520 MPa QUENCHED AND TEMPERED STEEL

A special order in accordance with AS1442 was undertaken. AS1442 only specifies a chemical composition range of a steel. Customer requirement also stated a minimum 0.2% Proof Stress of 520 MPa, and a Charpy Impact Test value at 0C in the longitudinal direction, using a 10 x 5mm specimen of 10 Joules minimum.

The following chemical composition was used.

Element Heat 1 Heat 2 Weight % Weight %

Carbon 0.15 0.16 Phosphorus 0.017 0.023 Manganese 1.46 1.56 Silicon 0.28 0.26 Sulphur 0.009 0.009 Nickel 0.038 0.055 Chromium 0.083 0.126 Molybdenum 0.004 0.006 Copper 0.020 0.019 Aluminium 0.040 0.032

About sixty tonnes of this product was treated at BIS. A proof stress range of 520-550 MPa was attained. Charpy test values on all plates produced (8.0mm) were in the range 60-100 Joules. The production of a tailor-made product for special requirements is a workable proposition here at BIS.

3.8.4 BISALLOY WITH BHN 400 Wear resistant steel plate with a BHN

400 has been produced at BIS. Using the chemical composition of BIS-500 as the starting point, the production process at Unanderra would be modified to obtain a plate with the nominated hardness. This is obtained by varying the tempering conditions tempering temperature and duration. Tensile properties and notch toughness would be similar to those of BIS-500.

Any fabrication or welding of this type of steel would need to follow the prescribed conditions set for BIS-500.

6/84 S3: Page 23

P-"c'r .11-W -

4.1 For 4.1.1 Cold f,'orroirig 4.12 tintrming

11.1.a.me Cutting

4.3 Shearing cn d Pune bin ,

4.4 Turning

4.39622>g

4.6 Grinding

4.7 Sawing

4.8 Mining

4.9 Surface Treatment

6/84 S4: Page 1

4. FABRICATION OF BISALLOY Fabrication of quenched and

tempered steels does not require any unusual equipment or procedure, but more care and control is needed than with plain carbon steels.

4.1 FORMING

4.1.1 COLD FORMING All Bisalloy grades of quenched and

tempered steels may be cold formed. However, the minimum radii of bend increases with the hardness and tensile strength of the steel.

BIS-80 can be readily cold formed or angle bent, provided sufficient power is available and suitable forming radii are used. Springback allowances must be greater than for structural plain carbon steel and will depend on the type of forming.* All bending is preferably at right angles to the direction of rolling. Plate edges should be deburred and, in some cases, rounded before forming.

With BIS-320, 360 and 500 wear resistant grades, it is recommended, where possible, that the bend axis be transverse to the rolling direction, as

much larger former radii are required to bend about the longitudinal direction, as can be seen in the table of recommended former radii, Fig. 4.1a.

For BIS-500, it is recommended that plate exceeding 12mm thickness should not be bent about the longitudinal axis.

The minimum recommended former radii were determined at 30C, and, where it is desired to bend these minimum radii, the plate temperature should be at least this value, but not exceeding the tempering temperature. The minimum former radii listed in the table were generally achieved by a "stitching" technique, using a number of adjacent discrete vee bends, each of a few degrees. When it is desired to cold form Bisalloy plate in a single pressing operation, larger radii should generally be used and the supporting vee former should be well lubricated. Also, when forming to minimum radii is required, it is recommended that plate edges should be dressed prior to forming, ensuring that flame hardened edges are removed completely.

See Springback Test table next page.

Minimum Former Radii in mm for Cold Forming Bisalloy Grades Plate

Thickness Bisalloy-80 T L

Bisalloy-320 T L

Bisalloy-360 T L

Bisalloy-500 T L

3.25mm 8 8 8 10 8 13 5mm 12 12 12 15 12 20 emm 15 15 15 20 15 20 25 50 8mm 20 20 20 30 20 35 40 70

10mm 25 25 25 35 25 40 50 90 12mm 30 30 30 45 30 50 60 110 16mm 45 45 45 60 45 75 85 20mm 65 65 65 75 65 100 100 25mirn 75 75 75 100 75 125 150 32mm 100 110 110 140 110 175 250 40mm 125 140 150 190 170 250 50mm 150 200 250 350 300

Note: These values are for plate at 30C. Attention is particularly drawn to the text regarding bending in a single operation.

6/84 S4: Page 2

RESULTS OF SPRINGBACK TEST ON BIS-80 Plate

Thickness

mm

Former Diameter

2Ro mm

Ring Diameter

After Springing 2Rf mm

Springback

2 (Rf Ro) mm

Test Ratio

Ro : Rf

6 197 245 48 0.80 10 197 221 24 0.89 16 197 219 22 0.90 25 197 212 15 0.93 6 394 605 211 0.65

10 394 473 79 0.83 16 394 461 67 0.85 25 394 444 50 0.89 6 834 2165 1334 0.39

10 834 1246 412 0.67 16 834 1388 554 0.60 25 834 1223 389 0.68 16 1626 5936 4310 0.27 25 1626 3445 1819 0.47

4.1.2 HOT FORMING Hot forming is generally not

recommended, because if tempering temperatures are exceeded, the properties of the steel will be impaired.

If hot forming is unavoidable, it is essential that the maximum re-heat temperatures be closely controlled and kept below tempering temperature of that particular grade in use. Under these circumstances, it is recommended the manufacturer be consulted.

4.2 FLAME CUTTING Flame cutting is widely used for these

steels, not only for the heavier sections that cannot be sheared, but also for lighter sections. Conventional techniques are suitable, with the same gas pressures, nozzle size and similar travel speeds being used as for cutting plain carbon structural steels.

When stripping plates, the use of parallel torches will help to minimise distortion.

In very cold conditions, say 10C or below, care must be taken to prevent edge cracks. Preheating to no more than 175C (100C for BIS-500) and slow cooling after cutting will facilitate subsequent machining as otherwise the

hardness of the flame cut edge may be as high as BHN 450.

Remember that excess heat during cutting may reduce the plate hardness to undesirable levels minimise the heat input as much as possible. Do not stack plates particularly when profile cutting.

4.3 SHEARING AND PUNCHING

Shearing and punching of the softer grades of quenched and tempered steels can be carried out providing a machine of sufficient capacity is available.

BIS-80 can normally be cold sheared up to about 25mm in thickness, although the necessary force is about three times that required for mild steel.

BIS-320 can be cold sheared to about 10n-im in thickness, but even larger shearing forces will be required.

Through hardened wear resistant grades above BHN 360 should not be considered for shearing.

Guillotine blades should be sharp and set with a clearance of approximately 0.25-0.40mm (0.010-0.015").

Maximum limiting thicknesses for cold punching are about half the shearing values.

6/84 S4: Page 3

1000 625 625 475 260

Mild Steel BIS 80 BIS 320 BIS 360 BIS 500

0.15 0.10 0.10 0.075 0.075*

Spindle Speed (rpm)

Feed Rate

(min/rev)

Material

Turning Tips: Seco DNMM 150608-37 Grade TP25

* In certain circumstances it may be necessary to increase the feed rate with Bisalloy 500 to avoid "polishing" of the workpiece by the tool.

SHEARING AND PUNCHING MAXIMUM LIMITING THICKNESS

GRADE BIS 80 BIS 320 BIS 360 BIS 500

SHEARING

25mm 10mm Not Recommended Not Recommended

COLD PUNCHING 12mm 6mm Not Recommended Not Recommended

4.4 TURNING

All Bisalloy grades, including those with hardnesses in excess of BHN 360, can be turned satisfactorily with carbide tooling, provided spindle speeds and speed rates are reduced from those normally employed when carrying out similar machining operations on mild steel. Reductions of 50-70% in spindle speed and up to .50% in feed rate may be necessary, depending on the hardness of the article being machined. High speed tools are generally not recommended.

As an example, the following settings have been found to give completely satisfactory results when turning cylindrical workpieces of 25mm diameter from the various Bisalloy grades. With increases in stock diameter, spindle speeds will naturally decrease.

TURNING

high powered and rigid equipment. Centre drilling is recommended as

good practice, particularly for the high hardness grades, as is the use of substantial backing plates to prevent the work "springing", due to the heavy feed pressures required.

The following data will provide a guide for setting up drilling operations. Experimentation will be required to determine the optimum conditions for individual machine shops.

When Brinell hardness runs 400 and higher, the drills should have a heavy web structure, thinned at the point, and be designed with a slower helix angle.

Countersinking presents no problem in any grade, provided an inserted carbide type cutter is used in accordance with supplier's recommended speeds and feeds for the hardness of the material.

4.5 DRILLING Drilling of the various Bisalloy grades

becomes more difficult as the hardness of the plate increases. However, the drilling of wear resistant plate up to BHN 400 is routinely carried out on suitable

DRILLING Steel Grade Point Angle

A Lip

Angle BIS-80 BIS-320 BIS-360

118 125 150

10 7.5 5

R.P.M. (upper figures) and feed per revolution for given drill size expressed in mm

6/84 S4: Page 4

.F VVVVVVVVVVVVVVV VVVVVVVVVVVVVVVVVVVVVVVVV

FLAME CUT SURFACE

CORRECT

Approximate Feeds & Speeds for Drilling Hardened Steels* Steel Grade

Peripheral Speed Metres per minute

3.175mm 6.350mm 12.700mm 19.050mm ' 25.400mm

2300 1150 575 385 285 Mild Steel 22.86m

.050mm .101mm .202mm .304mm .406mm

1370 685 340 230 170 BIS-80 13.716m

.038mm .063mm .127mm .190mm .254mm

920 460 230 150 115 BIS-320 9.144m

.025mm 0.50mm .101mm .152mm .203mm

460 230 115 75 55 BIS-360** 4.572mm

.025mm .050mm .101mm .152mm .203mm

* This table applies when high speed steel drills are used with a cutting fluid. If no fluid is used the speeds shown above must be reduced.

** Cobalt type high speed steel drills are recommended for this operation.

BLADE MOVEMENT DRILLING

BIS-500 Surface Speed Feed Inserts Grade

60-70m/min .15 - .22mm/rev WCMX R-51 GC015

Above information relative to tests done using Sandvik U drill 17.5mm to 58mm.

BIS-500 Surface Speed Feed Grade

30-40m/min 0.22 - 0.25mm/rev P25

Above information relative to test done using Sandvik delta drill 12mm to 20mm.

BLADE MOVEMENT

4.6 GRINDING All Bisalloy grades can be ground quite

successfully.

4.7 SAWING All Bisalloy grades can be cut with

power saws, provided lower blade speeds and up to 50% more blade pressure is used than when cutting mild steel.

Because of the high hardnesses associated with flame cut surfaces (up to BHN 400 - 450) sawing directly onto the flame cut surface should be avoided if possible.

It has been found to be desirable to use power saw blades normally recom-mended for cutting stainless steel - 4 or 6 t.p.i. blades have given satisfactory performance.

VVVVVVVVVVVVVVV

VVVVVVVVVVVVVVVVVVVVVVVVVVV

FLAME CUT SURFACE

INCORRECT

4.8 MILLING

Milling operations often entail dressing a flame cut edge or surface, and then subsequently milling bulk material to the desired surface finish and dimensional tolerance.

Care must be taken to make a first cut sufficiently deep to remove the heat hardened zone of the flame cut edge. Cutters must be sufficiently robust to take this heavy loading. In such

6/84 S4: Page 5

circumstances it is desirable that, due to the high hardnesses adjacent to flame cut surfaces, cutter speeds and feed rates for initial milling should be reduced to 40-50% of the speeds normally used when milling mild steel. The importance of adequate preheating prior to flame cutting and slow cooling after cutting to minimise edge hardening is again emphasised. Speeds and feed rates may be increased somewhat for subsequent bulk milling to 50-57% of the settings used for mild steel.

(a) Initial milling of flame cut surface Material Cutter Feed

Speed Rate (rpm) (mm/min)

Mild Steel 1800 125 140 BIS-80 700 75 BIS-320 700 75 BIS-360 700 75 BIS-500 600 75 (b) Bulk Milling Material Cutter

Speed (rpm)

Feed Rate

(mm/min) Mild Steel 1800 140 BIS-80 1400 100 BIS-320 1300 100 BIS-360 1000 100 BIS-500 900 100 3mm deep cut, 60mm dia. cutter equipped with three Seco Titan milling tips SPUN 120312 Grade S25M.

As with all machining operations, machine settings should be adjusted in relation to plate hardness such that milling rates would be proportionately lower for the higher hardness wear resistant grades than for Bisalloy 80.

4.9 SURFACE TREATMENT

All of the Bisalloy range can be surface treated to remove surface scale. Sand blasting, shot blasting or wire brushing are all effective. The Bisalloy range can also be painted with no danger to the product.

Storage indoors is advisable to keep the occurence of rust and pitting corrosion to a minimum. Complete water drainage should be provided to any plate stored outside. Identification of plate would be best colour coded.

6/84 S4: Page 6

SECTION FIVE

WELDING OF BISALLOY STEELS

5.1 Introduction

5.2 Manual Metal Arc Welding (MMAW)

5.3 Gas Metal Arc Welding (GMAW)

5.4 Flux Cored Arc Welding (FCAW)

5.5 Submerged Arc Welding (SAW)

5.6 Welding Considerations 5.6.1 Preheating 5.6.2 Electrode Drying 5.6.3 Fluxes 5.6.4 Arc Strikes 5.6.5 Repair Work 5.6.6 Welding Procedures

6/84 S5: Page 1

WELDING OF BISALLOY STEELS

5.1 INTRODUCTION The Bisalloy grades of quenched and

tempered steels are readily weldable by conventional welding processes. It is necessary to provide sufficient preheat and arc energy input to avoid heat affected zone (HAZ) cracking due to hydrogen but at the same time it is desirable that the weld metal and HAZ cool relatively quickly. The preheat and arc energy input should not become excessively high as the strength and fracture toughness of the steels will be impaired. Restrictions on high levels of arc energy input in welding the Bisalloy structural grade are particularly relevant where it is necessary to maintain the high fracture toughness of the parent plate. The maximum values of arc energy input for Bisalloy steel are given in the accompanying table.

Particular attention to the cleanliness of the joint preparations and the correct drying and storage of weld consumablees is necessary in the welding of quenched and tempered steels to avoid hydrogen cracking.

5.2 MANUAL METAL ARC WELDING - MMAW

MMAW can be used to weld quenched and tempered plate such as the Bisalloy range. Stick electrodes to the AWSA5.5 E11018-M or AS1586 E7618-M classifications are suitable for the welding of BIS-80 to provide comparable strength and ductility. In the most highly restrained weldments, a preheat of up to 150C may be necessary to avoid cracking in the plate, but for most purposes, a minimum preheat of 100C is sufficient, provided the arc energy input is greater than 1.51d/mm. Preheating is not

required for plate 6mm or less in thickness, provided the arc energy input is at least 1.25 kJ/mm.

It is necessary to restrict the heat input. Weaving should be avoided. A number of weld runs having an arc energy within the range 1.25 to 2.5 kJ/mm is preferable to heavy single welds deposited at higher arc energy inputs.

Suitable consumables recommended by the manufacturer for the MMAW of BIS-80 are: Alloycraft 11018G (CIG) Jetweld LH110-M (Lincoln) Austalloy 11018-TI (WIA)

In the case of wear resistant alloy, matching strength is not usually required, as most welding is for attachment purposes and in this regard the conventional basic low hydrogen electrodes to the AWS A5.1-E7018 or AS1552-E4818 classifications are suitable. Care should be taken to ensure the correct welding conditions apply preheating, energy input (see Section 5.6).

5.3 GAS METAL ARC WELDING-GMAW

Solid alloy electrode wires providing matching strength and notch toughness to BIS-80 are available for use with the GMAW process. These wires are to the AWS A5.28-80 specification ER110S-1 and are conventionally used with a gas mixture of Argon 2% Oxygen or Argon-5% CO,. Above the transition current droplet transfer in the GMAW process is by the highly efficient spray transfer mode.

For BIS-80 a preheat of up to 170C may be necessary for the most highly restrained weldments but lower temperatures are acceptable for less restrained joints or with high arc energy inputs but these should not exceed the values given in the table. Welds made with these alloy wires

MAXIMUM PERMISSIBLE ARC ENERGY INPUTS FOR BISALLOY STEELS

Welding Process

PlateThickness 3 10 mm 12 20 min 25 32 mm 40 100 mm

MMAW FCAW GMAW

SAW

2.5 kl/ mm 3.5 kJ/ mm 4.5 kJ/ mm 5.0 kJ/ mm

6/84 S5: Page 2

Wire Flux

Autocraft Ni-Cr-Mo Lincore M2 Fluxocord 42

BX505 880 Austmatic OP 121

(CIG) (Lincoln) (WIA)

may have difficulty achieving the 6.7t joint bend requirement of the structural and pressure vessel codes although the joint tensile requirement is readily achieved. An alloy wire suitable for use with BIS-80 is Autocraft Ni-Cr-Mo (CIG) which is normally used with Argoshield 61 and 52 or similar Argon CO, gas mixtures.

Wires for use in the GMAW process which provide matching strength to BIS-320 are also available to special order where this grade is used for structural purposes, while the harder grades BIS-360 and BIS-500 may also be welded by the GMAW process, providing that matching strength is not required. The conventional wires (eg AWS A5.18 ER705S-4) and shielding gases used for the welding of structural grade steels may be used for the welding of these harder grades.

5.4 FLUX CORED ARC WELDING- FCAW

The semi-automatic FCAW process is particularly suitable for the welding of quenched and tempered steels. Owing to low hydrogen content associated with this process, no preheat is normally required for plate up to 12mm in thickness, provided the arc energy is at least 1.0 kJ/mm. Should the arc energy be lower, or for thickness in excess of 12mm a preheat to 100C may be required. Matching strength and ductility to BIS-80 is normally achieved in the weld, while the high Charpy V notch impact values are also maintained, provided the arc energy inputs do not exceed the value given in the preceding table.

Suitable consumables are those to AWS A5.29-80 class E 11XT-X such as: Tensi-cor 110T (CIG) Fluxofil 42 (WIA)

These wires are normally used with CO2 gas shielding or argon-0O2 mixtures having at least 15% CO2.

In the case of wear-resistant grades BIS-320, BIS-360 and BIS-500, where matching strength is not required, the basic flux-cored wires such as Supre-cor 5-11A (CIG), NR-311 or NS-3M (Lincoln) and Fluxofil 31 (WIA) are suitable.

5.5 SUBMERGED ARC WELDING

Submerged arc welding consumables providing matching strength, ductility

and impact toughness are available for the welding of BIS-80. Care should be taken to ensure that the arc energy input does not exceed the values shown in the table. Multipass welds should be deposited rather than heavy single pass welds, while interpass temperatures should not exceed 200C. A preheat of 150C may be necessary for plate exceeding 16mm in thickness. It is recommended that root runs in joints to be welded by the SAW process be deposited by the MMAW process using stick electrodes to AWS A5.5 E11018-M class with subsequent backgrinding to sound metal. Welding consumables providing matching properties to BIS-80 are covered by AWS A5.23 and have classifications such as F11A6-ECM2-M2 for a flux cored wire and F11A6-EM2 in the case of a solid wire.

It is particularly important that submerged arc flux be correctly handled in the welding of quenched and tempered steels. Flux should be stored at a temperature in excess of 100C and generally baked at 400C if exposed to the atmosphere for more than 20 minutes. The manufacturers' recommendations for the baking of flux should be followed and, moreover, electrode wire should be kept clean and dry.

Wear resistant grades may also be welded by this process but, at present, SAW consumables to provide matching strength are not readily available.

5.6 WELDING CONSIDERATIONS

5.6.1 PREHEATING Control throughout the preheating

process is the most important variable in welding quenched and tempered steels. The purpose of preheating is to prevent cold cracking in the heat affected zone. The preheating temperature of Bisalloy Steels is dependent on grade, thickness and welding process.

When a weld cools rapidly, the heat affected zone may harden, causing a resultant decrease in ductility. Preheating prevents this by, retarding the rate of cooling of the weld, especially in the lower temperature region. The

6/84 85: Page 3

preheating areas should extend about 75mm on either side of the weld joint. Preheating is also effective in removing hydrogen from a weld (hydrogen promotes cold cracking) especially when it is maintained near the maximum interpass temperature for one or two hours after weld completion.

RECOMMENDED PREHEAT TEMPERATURES FOR BISALLOY STEELS

Plate Thickness Temperature 3-12mm 12-19mm 19-25mm 25-50mm 50-100mm Preheat 50-75C 75-100C 100-120C 120-140C 140-160C Maximum Interpass 150C 180C 200C 220C 230C As seen from the table, the preheat temperature is dependent on the thickness of the plate.

5.6.2 ELECTRODE DRYING It is a requirement of the low alloy

steel stick electrode specification AWS A5.5-80 that the mositure content of E11018 electrodes should not exceed 0.2 percent which may be compared with 0.6 percent for lower strength E7018 electrodes. While E11018 electrodes are supplied in hermetically sealed metal containers, they should be stored at a temperature of 120C after opening and rebaked at a temperature of between 370 and 430C if exposed to the atmosphere for more than half an hour, or if there is a doubt as to the moisture content. Only one rebaking is allowed.

5.6.3 FLUXES Fluxes for SAW should be dry and free

of contamination dirt, mill scale or other contaminants. After the container is opened, the flux should be placed in a drying area at a temperature of at least 250C for two hours. The flux should be in thin layers or agitated, so that it maybe uniformly heated and dried. The flux should then be used or placed in a storage oven at a temperature of at least 160C.

5.6.4 ARC STRIKES Arc strikes outside the welded zone

can result in cracks, particularly in dynamically loaded structures. All arc strikes should be made within the joint preparation.

5.6.5 REPAIR WORK In the repair of equipment where new

sections are inserted and welded to original plate sections, it is good practice to repair weld with electrodes of lower tensile strength such as E9018-M. The reason is plate materials and sections

have been highly stressed in service and may tend to warp or distort slightly during welding.

BIS metallurgists are always available to advise on welding procedures for quenched and tempered steels. Direct contact with BIS at Unanderra will yield the best result. 5.6.6 WELDING PROCEDURES

All flame cut or gouged surfaces must have 1-2mm removed by grinding. Weld preparations and at least 12mm on either side of the weld joint should be free from hydrocarbons (oil, grease, etc) paint, rust, scale to ensure good weld quality. The job or subassemblies should be positioned for downhand welding where possible. This will reduce the risk of weld defects and improve productivity. The use of backing bars facilitates high depostion rate downhand welding with continuous wire processes.

In order to prevent excessive heat affected zone hardening, it is important to maintain preheats between specified temperatures and welding heat inputs temperatures should not exceed 220C to prevent heat affected zone embrittlement. Check preheat with a surface thermometer immediately prior to welding. The following MMAW procedures for welding of static and dynamic loaded joints are provided for guidance. An undermatching weld metal is indicated for the dynamically loaded joint but it should be noted that this procedure would not comply with structural or pressure vessel code requirements. Another approach to overcome the hardened HAZ caused by the final surface runs is to use a temper pass deposited within 2mm of the edge of the underlying weld using full strength electrodes.

6/84 S5: Page 4

1-2 mm 16 mm

0-1 mm I

TYPICAL WELDING PROCEDURE Conditions: Static loading

Joint Geometry

Electrodes

Welding Currents

Welding Position

Bead Types

Preheat

Interpass Temp. Range

Post Heat

Butt Welding Sequence

3.2mm E7018 (AWS) 4.0mm E11018-M (AWS)

3.2mm 125 Amps AC 4.0mm 175 Amps AC

Flat

Stringer

90C

90-180C

Nil

(a) Root Pass 3.2mm E7018 (AWS) (b) Fill Passes 4.0mm E11018-M (AWS) (c) Grind root pass (e) Cool slowly in still air

6/84 S5: Page 5

0-1 mm -1.1 .- '

TYPICAL WELDING PROCEDURE Condition: Heavy Dynamic Loading

Joint Geometry

Electrodes

Welding Currents

Welding Position

Bead Types

Preheat

Interpass Temp Range

Post Heat

Butt Welding Sequence

3.2mm E7018 (AWS) 4.0mm E9018-M (AWS)

3.2mm 125 Amps AC 4.0mm 175 Amps AC

Flat

Stringer

90C

90-180C

Nil

(a) Root Pass 3.2mm E7018 (AWS) (b) Fill Passes 4.0mm E9018-M (AWS) (c) Grind root pass (d) Root Fill Pass 4.0mm E9019-M (AWS) (e) Cool slowly in still air (f) Buttering Passes 3.2mm E7018-(AWS)

6/84 S5: Page 6

SECTION SIX

QUALITY CONTROL AT BIS

6.1 Quality Assurance at BIS

6.2 Size Capacities of Steel Plate

6.3 Tolerances of Steel Plate

6.4 Tensile Tests at BIS

6.5 Charpy Tests at BIS

6.6 Hardness Tests at BIS

6.7 Identification & Certification of Bisalloy Plate 6.7.1 Identification 6.7.2 Certification

6.8 Services Available

6/84 S6: Page 1

Thickness mm

3.25 5

6-50 55 70

75 80 90

100

Width mm m

Length

1200 1500

6.0 6.0

1900, 2500, 3100 6.0, 7.5, 9.0 1800 6.0 1700 6.0 1500 6.0 1500 6.0 1500 6.0

6. QUALITY CONTROL

6.1 QUALITY ASSURANCE AT BIS

The National Association of Testing Authorities, Australia, (NATA) have registered a mechanical testing laboratory at BIS. The acceptance by the Council of the Association as a Registered Laboratory enables BIS to conduct a comprehensive test program, all which is certified by a NATA approved staff.

By being a NATA approved testing laboratory, all tests carried out by the laboratory staff are in accordance with Australian Standards appropriate to the particular test. The Australian Standards set a procedure and report of the test undertaken. NATA approval signifies that the Australian Standards are completely adhered to by the staff.

The qualified laboratory staff and the precise testing equipment are also registered under AS1822-1975, Suppliers Quality Control System Level 2. AS1822 establishes requirements for a com-prehensive quality control system. It identifies each of the elements of a system to be designed, established and maintained by the supplier for the purpose of ensuring that supplies and services conform to control requirements.

If required by the customer, additional mechanical tests, including ultrasonic non-destructive testing, can be conducted at BIS. Of course, extras may apply for any additional testing. Direct contact with the manufacturer will yield the best result.

Upon request and approval, the Quality Assurance Manual can be supplied. The Quality Assurance Manual contains information including quality policy statement, operating i