BRADKEN ENERGY PRODUCTS

March 2012

Elaine Thomas, Director of Metallurgy Bradken Tacoma

Valve Manufacturers Association

of America

March 2012

Casting High Quality

C12A

© 2011 BRADKEN®

ASTM A217 C12A and ASME Code case 2197-7

Chemistry

Element wt%

C 0.08 – 0.12

Mn 0.30 – 0.60

Si 0.20 – 0.50

P 0.020

S 0.010

Mo 0.85 – 1.05

Cr 8.0 – 9.5

Nb 0.060 – 0.10

V 0.18 – 0.25

N 0.030 – 0.070

Al .02

Ti .01

Zr .01 2

© 2011 BRADKEN®

QUALITY SYSTEM MANUAL

3

© 2011 BRADKEN®

CERTIFICATES

• ASME

• ISO 9002:2002

• Det Norske Veritas

• Nuclear Industry Assessment Committee (Audit)

• American Bureau of Shipbuilding

• LLOYDS Registrar

• Boeing D6-56202 4

© 2011 BRADKEN®

EMPLOYEE TRAINING

• Training Manuals for Skilled Positions

• Continuing Education From Professional Society Participation – American Society for Testing and Materials

– Steel Founders Society of America

– American Foundry Society

– American Welding Society

– American Society for Non-destructive Testing

• Continuing Education From National Conferences – Offshore Technical Conference

– Submarine Industrial Base Conference

– Marine Machinery Association

– Hydro Vision

– Power-Gen

• Training Manuals for Skilled Positions

• Continuing Education From Professional Society Participation

– American Society for Testing and Materials

– Steel Founders Society of America

– American Foundry Society

– American Welding Society

– American Society for Non-destructive Testing

• Continuing Education From National Conferences

– Offshore Technical Conference

– Submarine Industrial Base

– Marine Machinery Association

– Hydro Vision

– Power-Gen

5

© 2011 BRADKEN®

THE CASTING PROCESS

GRINDING &

WELDING INSPECTION ROUGH

MACHINE

RISER REMOVAL

INITIAL HEAT

TREATMENT

SHAKEOUT & BLAST

POURING PATTERN MAKING

MOLDING CORE MAKING MOLD

CLOSING

ENGINEERING

REVIEW

FINAL INSPECTION SHIPPING

ORDER ENTRY

CONTRACT

REVIEW

HEAT TREATMENT

FOR PROPERTIES HEAT TREATMENT

6

© 2011 BRADKEN®

ENGINEERING REVIEW

• Process Simulation (MagmaSoft)

• Process Instruction/Documentation (Process Sheet)

7

© 2011 BRADKEN®

CORE MAKING • Core Ticket

• Process Sheet

• Sign-Off Sheet

8

© 2011 BRADKEN®

MOLDING

Qty:

Cookie Cores Break Off Cores

Rigging

Qty. Qty. Qty. Qty. Qty. Qty.

Qty. Qty. Qty. Qty. Qty. Qty.

4

Qty. Qty. Qty. Qty. Qty. Qty.

Size

Guide: Br=brick, BO=break off core, C=cookie core, D=dome, Nd=neck down, sp=stove pipe, TB=test bar, F=Flange

Size

Eng. Comments:

NO 903

Ht.

Blind

Sand

Chills:

Facing Sand:

Ht.

Eng.

Facing Sand:

n/a

16-8x8x8

si 2 wood lock pieces

2/7/11 Material:

n/a

per cstg

Cast in mold: WC Date:

n/a

Test bar comments:

1

Customer:

Tile Size:Gate Type:

Molding TP 4370-1

Pattern No.

CANYON Serial No:

tile 5,4 Quantity:10-3096

LengthWidth

Width Length

168168

Eng. Comments:

Drag

Flask Size

168 48 Chills:

Ht.SizeHt.

Open

Sleeves

Size

Size

Size

Loose Pcs:

Size

Blind

Sleeves

Ht. Ht.

Ht.

18

Size

22-popoff vents sticks

Ht. Ht.

5x5 Spacing:

Size

Loose Pcs:Height

Special Id:

Cheek:

A743 CA6NM

168

Sprue Size

Ht.

Paint popoff vents thoroughly with silver parting. Using 4" tile, risers will interconect with each other, 12" hi into the riser measuring from

the contact surface and form a loop around the center of the part

48

Test bar: M

Size

HeightFlask Size

Cope

Open

Sand

standard

Size Ht.

Ht.

Size

SizeSize Ht.

24

SizeHt. SizeHt. Ht.Size Ht.

si

SizeHt.

• Mold Ticket

• Process Sheet

• Sign-Off Sheet

9

© 2011 BRADKEN®

MOLD CLOSING

10

© 2011 BRADKEN®

MELTING • Radioactivity Test on incoming

scrap

• Chemical Analysis

– Traceable to National

Standards

– Internal Proprietary Chemistry

• Gas Analysis

11

© 2011 BRADKEN®

C12A is AOD refined

12

© 2011 BRADKEN®

ASTM A217 C12A and ASME Code case 2197-7

Chemistry

Element wt%

C 0.08 – 0.12

Mn 0.30 – 0.60

Si 0.20 – 0.50

P 0.020

S 0.010

Mo 0.85 – 1.05

Cr 8.0 – 9.5

Nb 0.060 – 0.10

V 0.18 – 0.25

N 0.030 – 0.070

Al .02

Ti .01

Zr .01 13

© 2011 BRADKEN®

Cross section of an AOD Vessel

14

Tuyere

© 2011 BRADKEN®

Tuyere allows Nitrogen injection

15

oxygen

N or Ar

© 2011 BRADKEN®

Issues with casting C12A

Nitrogen –

– keeping N in solution

• chemistry

• low turbulence gating

16

© 2011 BRADKEN®

POURING • Document Pour Weight, Time, Temperature

• Sign-Off Sheet

• Problem Report

17

© 2011 BRADKEN®

SHAKEOUT AND BLAST

• Time to Shake Out

• Visual Evaluation after Blast

18

© 2011 BRADKEN®

HEAT TREATMENT • Heat Treat Procedures

• Furnace Uniformity Survey

• Time & Temperature

• Fans for cooling

Stress prior to Riser removal; Aus/fan Cool + Temper (1350< T <

1450F); PWHT

ASME code being discussed: PWHT would be Aus/fan Cool + Temper

(1350< T < 1450F);

19

© 2011 BRADKEN®

Microstructure

20

© 2011 BRADKEN®

INSPECTION

•Personnel

• ASNT qualified inspectors

Level III on staff

Procedure and Acceptance Standards

• ASME, ASTM, Internal Quality Procedures

Visual

Dimensional

Magnetic Particle / Liquid Penetrant

Ultrasonic

Radiography

21

© 2011 BRADKEN®

INSPECTION

Which should you choose? • Visual

• Dimensional

• Magnetic Particle / Liquid Penetrant

• Ultrasonic

• Radiography

Choices:

critical areas like areas to be welded,

high stress

fatigue areas

Max feasible volume? what level? (1,2,3,4)

22

© 2011 BRADKEN®

Welding C12A

Welding & Hydrogen

Pipe must be welded in dry environment.

Welding followed by hydrogen diffusion cycle.

No evidence (so far) that Castings have the

same issues as pipe. Unlike Pipe, Casting

receive upgrade welds followed by low

temperature PWHT.

23

© 2011 BRADKEN®

C12A

24

© 2011 BRADKEN®

Issues with casting C12A

25

© 2011 BRADKEN®

the intercritical region

• Perhaps the most common problem with Grade

• 91 is post-production exposure to temperatures in

Perhaps the most common problem with Grade 91 is post-production exposure to

temperatures in the intercritical region—where the tempered martensite begins to

transform back into austenite and below the temperature where phase transformation

is complete.

This can happen in the field where thermal blankets are used for PWHT. If not used

properly (e.g. overlapped blankets), regions can get too hot putting the metal into the

intercritical zone.

When Grade 91 is heated into this intercritical region, the material partially reaustenitizes,

and the resulting structure will have substantially reduced creep-rupture strength

In the worst case, this material will have lower creep-rupture strength than that of

traditional Grade 22.

26

© 2011 BRADKEN®

Type IV Cracking in Modified 9Cr-1Mo Steel Weld Joint

• Type IV cracking in the heat affected zone (HAZ) of weld joints limits the life

of the component.

• Creep tests performed on the steel and its joint revealed that the type IV

cracking occurs in the inter-critical region of HAZ, which is sandwiched

between relatively higher creep resistant constituents of the joint.

• The constrained localized deformation leads to the pronounced creep

cavitation in the soft intercritical region of HAZ of the weld joint to yield type

IV failure.

• The creep rupture life reduction due to type IV cracking in the weld joint of

the steel was found to depend on the applied stress and test temperature.

• Based on the study, the reductions in 105 hours creep rupture strength of

the steel weld joint are estimated as 18 %, 30 % and 45 % of base metal

strength at 823 K, 873 K and 923 K respectively.

( i.e. 1022F, 1112F, and 1202F)

27

© 2011 BRADKEN®

28

© 2011 BRADKEN®

ASME New C12A considerations

• ASME Section I Code Case 2192 permits the use of

A217 C12A and A426 CP91 castings in the construction

of boilers. The case has been revised several times to

tighten requirements to deal with problems encountered

with this grade (in both its cast and wrought product

forms).

29

© 2011 BRADKEN®

ASME New C12A considerations

• Volumetric inspection of castings (per S5, RT, or

S7, UT, of A703) has been made mandatory,

with the choice of the inspection method to be at

the discretion of the material manufacturer

unless stipulated otherwise in the PO. – ASME Section I, PG-25 applies an 80% casting quality factor to the allowable stresses

of pressure containing castings; but permits use of a 100% factor if castings are RT

and MT examined.

– Castings with up to a 4½ in. nominal body thickness require partial RT, while larger

castings require 100% RT.

30

© 2011 BRADKEN®

ASME New C12A considerations

• A full normalizing and tempering heat

treatment has been made mandatory

following the completion of any major

repair to the casting.

• Type 4 weld failure w.r.t. stress rupture – especially bad in large

welds - Piping issues with thermal blankets which caused

overheating.

• FC+T eliminates the type 4 issues in the weld HAZ

31

© 2011 BRADKEN®

ASME New C12A considerations

• It is required that compliance with the

specified temperature ranges during any

heat treatment operation be demonstrated

by thermocouples placed directly on the

casting or batch of castings and that a

record of these operations be provided to

the purchaser.

32

© 2011 BRADKEN®

ASME New C12A considerations

• The hardness requirements currently in the two material

specifications, SA-217 and SA-426, have been added to

the Code Case.

• This has been discussed previously in A01.18 and the

185 HB minimum hardness for this grade was

accepted by the ASME committees, even though this

is lower than the 190 HB minimum hardness required of

wrought grade 91.

• The required hardness range is the same as that

required by A217/A217M-11 paragraph 7.2 for C12A and

by Table 3 of A426/A426M for CP91.

33

© 2011 BRADKEN®

ASME New C12A considerations

• It has been made mandatory that the location of

all weld repairs on a casting be recorded and

that for major weld repairs the dimensions of the

repair be recorded, and it is required that this

information be documented either on the

Material Test Report, for repairs made by the

material manufacturer, or on the Manufacturer's

Data Report, for repairs performed by the Boiler

Manufacturer.

34

© 2011 BRADKEN®

ASME New C12A considerations

This requirement is not relevant to material manufacturer, but

might be relevant to valve and pump manufacturers.

It has been stipulated that in cases where the requirement

to either re-heat treat or replace a portion of the casting

that has been heated above 1470°F is waived due to the

fact that the allowable stress values used are less than

or equal to those used for Grade 9, the use of the waiver

must be recorded on the Manufacturer's Data Report.

35

© 2011 BRADKEN®

ASME New C12A considerations

• Some of these proposed changes are unnecessary and

impractical.

• Not all users want or need these restrictions.

• Mapping all weld repairs is impractical. Majors only.

• Re-normalizing and tempering a finish machined casting

is impossible.

– Dimensions will change and/or warp.

36

© 2011 BRADKEN®

DISCUSSION

37