Stainless Steel, Our Bright Ally Tank Varieties and Choice of

January 2010Edition No. 49

English

Stainless Steel, Our Bright Ally...

Tank Varieties and Choice of Milk Coolers...

Weldability of Stainless Steels...

Tersainox and The Production of Liquid Gold...

SiloTank for Nitrate Transport...

Coal Wagons in 3Cr12...

In 1985, South Africa, it was built the �rst monocoque CCL coal wagon in 3CR12 ferritic stainless steel for the transport of coal, replacing CORTEN steel widely used until to day (high resistance steel to oxidation). This change generated a revolution in the manufacture and use of CCL type wagons, many thousands of these new wagons have entered service in South Africa and then spread to the world.

This is the case of the CCL "JUMBO" wagons, 82 ton load capacity, which are built using 6mm thick 3CR12 in the area for downloads (tubs) and 4mm wall thickness for the sides. At that time, 1985, wagons constructed series Nº63-636-106 and Nº63-535-114 were selected for inspection in time. In 1986 the �rst inspection is carried out without relevant observations. 13 years later, in 1999 is the second general inspection, the two wagons are still in excellent condition; for example, high-abrasion areas on the sides where the coal is lowered, were with a smooth, shiny, and excellent sliding capability. The base material shows no signs of 3CR12 fatigue or pitting in the welded zones of these wagons. On this basis, inspectors extrapolate that the cars could last about 50 years more.

There is another case of coal wagons manufactured in South Africa using 3CR12, on that occasion it was a �eet of 58 wagons for rail transport from the open pit coal mine coal Duvha and the Middleburg port. Each wagon has a capacity of 57 ton, open, loading from above and unloading wagon below by either side of the wagon. 3CR12 ferritic stainless steel was used in the main body, discharge doors, under the chassis and reinforcements. After 10 years of service, the cars were inspected with excellent results, his condition of service was excellent, with no noticeable wear and no sign of fatigue or defective welds.


Edition No. 49English

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Page No. 2Edition No. 49English

Finally, the material 3CR12 showed virtues of resistance to corrosion and abrasion, always considering the cars in the following case: CCL type wagons are widely used in the journey from the internal coal mines of South Africa to the Richard's Bay port terminal where coal is embark over ships and where the wagons are exposed to marine corrosion for the port. While 3CR12 wagons show to be free of corrosion inspections, CORTEN steel wagons showed serious problems of corrosion and wear on their surfaces. At the port, the corroded surfaces of the wagons tend to lift material and then when there are loaded at the mines, the material is knocked o� by the coal, generating a continuous wear of the plates. This situation does not occur with 3CR12.

In conclusion, replacement of CORTEN steel by 3CR12 ferritic stainless steel in the freight wagons in South Africa, was a total success for its longer life and lower maintenance management, it meant a sharp change in the railroad industry to start using 3CR12 in the manufacture of wagons worldwide.

Think 3CR12. Think Tersainox SA

We will be happy to answer your queries and support their projects.

Guillermo Rudolph.Sales Engineer.TERSAINOX S.A.

In metallurgy, stainless steel is de�ned as a steel alloy with a minimum of 10% chromium content by mass. Stainless steel is corrosion resistant, since the chromium or other metals it contains, has high a�nity for the oxygen and it reacts forming a passivation layer, thus preventing corrosion of iron. However, this layer can be a�ected by some acids, causing the iron to be attacked and oxidized by intergranular mechanisms or generalized pitting. It contains, by de�nition, a minimum of 10.5% chromium. Some types of stainless steel also contains other alloying elements, the main being nickel and molybdenum.

Like all types of steel, stainless steel is not a simple material but is an alloy material. What they have in common is that all steels the main component (element forming the alloy) is iron, with the addition of a small amount of carbon. Stainless steel was invented in the early twentieth century when it was discovered that a small amount of chromium (usually a minimum of 10%) added to ordinary steel gave him a shiny appearance and did extremely resistant to dirt and oxidation. This resistance to oxidation, called "corrosion resistance" is what makes stainless steel di�erent from other types of steel.

Stainless steel is a solid material and not a special coating applied to steel to give common “stainless” features. Common steels, and even other metals, are often covered or "washed" with white metals such as chromium, nickel and zinc to protect their surface or give them another surface features. While these bathrooms have their own advantages and are widely used, the danger is that the coating can be damaged or deteriorate in some way that would elimate the protective e�ect. The appearance of stainless steel can, however, vary and will depend on how it is produced and its surface �nish.



Page No. 3

A very Different

It is not a lining ...

Since its inception in 1997, Tersainox SA aim and dedication is to share a universe of solutions and development of stainless steel equipment.

Designed with the highest quality and providing strong support for the projects in the Industrial market, Mining, Transport and Food. For this, a large team of specialists and professionalscollaborate in the manufacture, development and assembly. Our fabrications meet international standards and our engineering apply API 650, ASME and Chilean standards.

We have won nationally and internationally recognize prestigious in the handling of the noble family of these materials: AISI 304L, AISI 316L, 3Cr12, Duplex steel LDX 2101, SAF 2304, 2205, 254 SMO, 904-L, AL6 XN, HASTELLOY.

Tersainox SA today provides solutions to a complete line of equipment for transport and storage of hazardous, liquid, powder or granules, such as: Palletank ®, Silotank ®, TANKTAINER ®, Semi Tank Trailer, Tank for Sulfuric Acid Transport and Fuel , Equipment multimodal.

The use of stainless steel in the industry in pippings, spools and others is the best solution to develop their projects. Our company has developed several lines of products of excellent quality within which we can mention: Pipings, Spools, drainage systems, platforms, catwalks, ladders, �oor grills, expansion joints, stainless steel cathodes, among others.

Today we can say that Tersainox SA is a company of professionals who daily deliver a comprehensive work to our distinguished customers and project development, experience and guarantee sustainability over time.



Page No. 4

Tersainox and our Brilliant Ally...

Patricio Campos C.Mining and Industrial Division.

TERSAINOX S.A.


- Open or Closed.

The advantage of OPEN TANKS is that they are simple in construction (in relation to the others) and are wash by hand. This means that open tanks are cheaper than closed tanks both in terms of buying and cleaning costs. In large open tanks, the biggest di�culty is manual cleaning.

The CLOSED TANKS are more expensive in construction and should always be cleaned automatically, which is also more expensive. One advantage of these respects the above is that a larger volume capacitycan be installed per square meter of �oor area.

In the practice, open tanks with hand wash are used up to 1.880 liters(vertical cylindrical open) and closed tanks with automatic washing increased capacity to 14.000 liters (vertical cylindrical close and horizontal cylindrical). Where an automatic cleanup is required, it is also possible to provide small closed tanks with this type of washingeither vertical or horizontal cylindrical depending on area of installation available.

- Speed of cooling.

The quality of milk at low temperature is signi�cantly determined by the speed at which the milk is cooled under certain critical conditions. This should be remembered as the cooling of the milk is always associated with the agitation of it. The 2 most important conditions are:

+ 10 º C. The temperature of the milk must be brought below 10 º C as quickly as possible in order to prevent as far as possible the agitation of warm milk and especially to prevent the rapid growth of bacteria.

+ 4 ° C. The temperature of the milk must be taken to a storage temperature of 4 º C as quickly as possible in order to inhibit the multiplication of bacteria (bacterial).

At this point it is important to consider the kinds of bacteria called Psychotropic and Psychrophiles, cold tolerant and cold-dependent, respectively, these conform the most annoying group of microorganisms in the dairy industry because they reproduce relatively rapidly at temperatures of 7 º C (+2 °). The predominant genus of this group is of the Pseudomo-nas.

Psychotropic bacteria can grow at low temperatures, 4 to 15 º C, but have optimal growth at temperatures above this range. These organisms a�ect especially the life of chilled dairy products.



Psycrophilic bacteria grow best at refrigeration temperatures, this means, between 4 and 15 º C.

The tanks should not come to freeze the milk due to loss of milk and cleaning problems since a layer of frozen milk left in the tank represents a loss, clogged surfaces are more di�cult to clean and does not reach an e�ective temperature for wash, also the ice crystals can damage the equipment when the tank is emptied with the wash pump to start grooming.

- Tank construction of quality milk cooler.

Requirements:

a) The contamination of milk powder, undesirable microorganisms and / or tastes smells of others must be prevented. b) It must be possible to clean both internally and externally with ease. c) You can not have any possibility of corrosion. d) Compliance with international standard ISO 5708, both a tank for 2 and 4 milkings.

Selection of materials :

As a rule it is advisable that all those areas which will come into contact with milk and / or cleaning liquids or water of condensation should be made of real stainless steel. Easy to clean and non corrosive. As we look to existing materials are an array of possible options, and there are di�erences in the designation of stainless steel according to the country, so there is enough confusion in this matter.

The stainless steel tanks used for milk coolers shall comply at least with point 11 of paragraph 13 of ISO 683 which stipula-tes the following composition: Chromium : 18 % Nickel : 8 % Carbon : < 0,06 %

All stainless steel manufacturers today provide authentic stainless steel which meet these conditions so that there should be no di�erence between the steel of di�erent providers of tanks. In today's language this is called stainless steel AISI 304.

Some manufacturers of milk coolers tanks occupy a cheaper ferritic steel containing little or no amount of nickel to its outer covering, and this is therefore called chromium steel (decorative), This chrome steel is more susceptible to corrosion than CrNi steel. This can be checked with a magnet (ferritic steel is magnetised).

It is clear that the use of other materials (such as plastics) as a replacement for real stainless steel or using steel admittedly lower quality, makes the pond cooler milk a little cheaper, but also qualitatively inferior (in quality and durability).



Quality of welds :

In particular welds those surfaces which come into contact with milk and cleaning agents must be polished termination and shall not exhibit cracks or pores. The force and weld strength of corrosion should be at least equal to the base material.

Polished surfaces :

All metal surfaces coming into contact with the milk must have a roughness of Ra> 1.0 um (paragraph 5 of ISO 5708).

Inner shell :

Should be designed so that the measured volume (nominal) is 90 to 95% of the maximum volume allowed.

All inside corners of the inner tank which form an angle of less than 2.36 radians (135 degrees) must have a radius of not less than 25 mm. Any component which is permanently �xed inside the inner tank must be soldered to this. Welds shall have a radius of not less than 6 mm. and angles must be no larger than 1.57 radians (90 degrees). Any component that does not meet these requirements must be possible removal.

- Agitation.

The agitation of the milk has a threefold purpose :

a) Place the milk in motion so that the heat transfer in the evaporator is adequate. b) To prevent frozen milk. c) To ensure that the milk fat remains proportionally distributed so that no formation of a cream layer at the surface.

In this regard there are a number of other requirements including :

a) The turmoil should not be too quick so not to allow air to be trapped in the milk, with the risk of beating or separation of the fat. b) Action by the agitation should be e�ective when the pond is completely full and when there is only a small amount of milk in the pond.c) It shall be possible to clean the palette of the agitator.



- Tanks of 2 and 4 milkings :

It may be obvious what these terms mean but I believe it would be appropriate to review them:

2 milkings : Is the tank that is capable of cooling the majority of its capacity within a period not exceeding the establish (2,5 to 3 hours). Example: 500 liters tank, the morning milking of 250 liters and in the afternoon the same amount, making the tank full and when passing the milk collection truck it must be cool. Your choice will depend on several factors, country, amount of milk obtained, a collection of industry (daily or everyother day, etc.). This tank is more expensive than 4 milking tank, equal capacity, for possessing twice the cooling power and in some cases double jacket evaporator (chiller).

4 Milking : It is a tank that is capable to cool a fourth of it capacity in a period not exceeding the requirements. Example: 500 liters tank, morning milking of 125 liters, 125 liters in the afternoon, the next day the same routine and that day passes the collection truck to remove the milk (500 liters, two-day milking).It is cheaper than the 2 milking tank to own half of cooling capacity and also be more easily built. The choice will depend on the same conditions as for the 2 milkings.

I hope this article will be useful especially for the dairy producer in any country and would like to remind you that it's almost a law in this cold milk industry:

“THE COLD CHAIN IS FUNDAMENTAL IN THE QUALITY OF THE MILK BUT IT DOESN´T IMPROVED IT, IT ONLY KEEP THE QUALITY OF THE PRODUCT”

Our company provides this type of equipment manufactured in Chile with Italian technology, with capacities ranging from 300 to 14.000 liters, and now we are heading in the search for country representatives.


Fernando E. Mayora.Commercial Manager.

FICOM S.A.

Page No. 9

Tersainox, a leader in the manufacture of stainless steel equipment, gives to you this information of weldability of these steels, with the aim of letting you know how we attack the characteristic problems of these alloys, preventing problems that may result, processes poorly executed welds.

� Stainless steel is an alloy of Fe + Cr, Where Cr 3 10.5% amount. � With the addition of other alloying elements (Ni, Mn, N, Mo, C, Si, Nb, Ti, Ta, etc..), we improve its physical properties (mechanical properties) and their chemical properties (corrosion resistance and high temperatures).

Designation of stainless steel is made according to:



Plate Tubes Bars Pipe Fittings Forgings

A473

AISI UNSASTM

316L S31603 A167 A213 A249 A312 A403

These are classi�ed as:

Austenitic stainless steel.

Ferritic stainless steel.

Martensitic stainless steels.

Precipitation hardened stainless steel. - Grade Semiaustenítico. - Grade Martensitic. - Grade Austenitic.

Duplex Stainless Steels.

- Austenitic steels:

� Family largest industrial use. � High resistance to corrosion. � High toughness at low temperatures. � Susceptible to pitting corrosion in chlorides media. � Chemical composition property: Cr : 16 - 30 %. Ni : 3,5 - 38%.

� Examples: 201, 202, 301, 304, 308, 310, 316, 316L, 317L, 321, 347.



- Ferritic Steels:

� Low tenacity. � High mechanical resistance. � Resistant to corrosion at high temperatures. � Easy to work at low temperatures. � Chemical composition property: Cr : 11 - 30 %.

� Examples: 405, 409, 430, 434, 439, 444, 26-1, 29-4, 29-4-2.

- Martensitic Steels:

� The heat treatment determines: - High mechanical resistance. - High hardness. - High toughness. � Good performance in high temperature service. � They are resistant to corrosion, erosion and cavitation. � Chemical composition property: Cr : 11 - 18%. Ni : 0 - 5%.

� Examples: 403, 410, 410NiMo, 414, 420, 422, 431, 440A, 440B.

- Precipitation Hardened Steels:

� High mechanical resistance. � Good resistance to corrosion and oxidation. � Acceptable ductility and toughness. � They can be hardenable. � Chemical composition property: Cr : 11 - 19%. Ni : 1,5 - 28%.

� Examples: 17-4 PH, PH 15-7 Mo, Almar 363, Custom 450, HNM.



- Duplex Steels:

� They are those with the highest resistance to corrosion: Good resistance to pitting corrosion. Good resistance to stress corrosion. � High mechanical resistance. � Chemical composition property: Cr : 20 - 30%. Ni : 5 - 10%.

� Examples: 255, 2205, 2304, NU744LN.

Characteristics of stainless steel:

Properties of stainless steels:

TypeMicrostructure at

ambient temperature

Austenitic Austenitic

Machinability

Easy

Solderability

Good

Features ferromagnetic

Non Magnetic

Hardened by heat treatment

Non hardening

Ferritic

Martensitic

Precipitation Hardened

Duplex

Ferrite Magnetic Non hardening Easy Regular

Martencita

Austenitic + CarbidesMartencita + Carbides

Austenitic + Ferrite

Magnetic

Magnetic

Magnetic

Hardenable Di�cult Regular

Hardenable EasyRegular

Good

Non hardening Easy Good

TypeDensity (gr/cm3)

Carbon Steel 7,8

Resistivity(10-6 Ω .m)

12

Fusion Range (°C)

1538

Expansion Coe�cient0 a 538° C

(10-6 mm/°C)

11,7

Thermal Conductivity

(W/m.°K)

60

Austenitic

Ferritic

Martensitic

Precipitation Hardened

7,8 17,0 - 19,2 18,7 - 22,8 69 - 102 1400 - 1450

7,8

7,8

7,8

11,2 - 12,1

11,6 - 12,1

11,9

24,4 - 26,3 59 - 67 1480 - 1530

28,7 55 - 72 1480 - 1530

21,8 - 23 77 - 102 1400 - 1440



- Weldability of Austenitic Steels:

� It is those who are soldered in a greater % (representing about 80% of the manufacturing industry). � Concentrate the heat (low thermal conductivity). � When heated deform easily (high coe�cient of expansion). � There are 3 main problems that can occur when solding: - Sensitization. - Hot cracking. - Formation of sigma phase.

Sensitization:

� Sensitive to the formation of chromium carbides in the range from 430 to 870 º C, which precipitate at grain boundaries, this can occur if during cooling after welding of the joint exposure is prolonged in the indicated range. � Therefore decreases the free Cr at surface and decrease its resistance to corrosion. � If it is form a large amount of chromium carbides, they can lead to the formation of a �ssure. � This phenomenon is known as intergranular corrosion.

How to prevent this: � Low heat input during welding and quenching: Low amperage. Cords straight and thin, a maximum width of 2.5 times the diameter of the electrode. Use short arc. � Use of input materials type ELC or stabilized material Nb (347) or Ti (321). � Heat treatment of austenitizing (allows dissolve carbides Cr), heat to 1100 º C and then rapidly cooled (water).

Hot Cracking: � It manifests itself in the welded joint in the form of random cracks or in the ZAC, if the ferrite content in weld metal is not properly controlled. � Occurs when the piece is subjected to restrictive conditions, generating hot cracks above 1250 º C, in areas where the liquid phases of low melting point are grouped into the grain boundaries, creating a decoherence between them. � The trace elements that are likely to form liquid phases are: P, S, B, Ni, Si Ti.

How to prevent this: � Use �ller material containing more than 3% ferrite, you can check the % ferrite by: Constitutional diagrams: Schae�er, DeLong, Hull, WRC-1988 and WRC-1992. Magnetism measurements: Magna - Gage.


Selección del Proceso de SoldaduraSOLDADURAPOR FUSION

ARCO ELECTRICO

SMAW(ARCO

ELECTRICO MANUAL)

GTAW(TIG) FCAW

SAW(ARCO

SUMERGIDO)

ELECTRODO VARILLA ALAMBRE TUBULAR

GMAW(MIG/MAG)

ALAMBRE MACIZO

PAW(PLASMA)

� Rapid quenching (cracking occurs at high temperatures). � Use short arc to avoid the entry of N material to the weld puddle (N is an element gammageno). � Never leave craters at the beginning or the end of welding. The concave areas favor this phenomenon.

Sigma phase formation: � The sigma phase is a hard and brittle phase. � It is formed when the weld is maintained at temperatures between 600 and 800 º C for prolonged periods. � The sigma phase substantially reduces the toughness of the welded joint and should be considered if the marriage joint will work or be subjected to heat treatment in the indicated range. � Deposits with ferrite content above 15% are susceptible to this type of phenomenon.

How to prevent this: � Low heat input during welding and fast cooling. � Using �ller metal % ferrite containing less than 15%, is feasible to employ constitutional diagrams. � Ensure that the base metal have levels below 15% ferrite.


Marcelo Molina.Sales Engineer.TERSAINOX S.A.

Illustrative image in Spanish

Tersainox and The Production of Liquid Gold...

Tersainox once again demonstrated its leadership and consolidation in the manufacture of equipment for 100% of the largest oil olive plant in the country.

Our olive oil is well positioned in the domestic market and this success was achieved thanks to obtain oil in a good way; in other words, with fresh and healthy fruits, with a gentle extraction and with the highest technology, this is where Tersainox goes in giving us tanks according to our requirements, which are completely sanitary and with a excellent presence, which has permited us closing new contracts.

Remarks by the General Manager of the oil olive plant.

In Tersainox we deliver to our new client, the largest installed capacity of tanks with the square feet arranged for them.

The tanks had to meet customer demands for easy handling of the oil, along with being 100% sanitary and with a fund with good drainage and it should match the daily harvest of olives.

In addition to all the requirements, they must be manufactured in a minimum time since the close of business performed well to restrict the harvest.

But thanks to the experience of Tersainox tank were managed to deliver on the date committed, high quality, certi�ed and European steels with excellent installation and anchoring of these.


Eric Miranda Lagos.Food and Spirits Division.

TERSAINOX S.A.

Page No. 15

Again Tersainox with his Transportation and Logistics Division has been recognized by our customers.

We have designed and manufactured a Silotank in Stainless Steel AISI 304-L with a capacity of 45m3.

Tersainox customer which already has more than 20 units of our manufacturing equipment, has decided again to rely on the quality of Tersainox equipment for their excellent performance, versatility and behavior in the processes of loading, transfer and discharge of nitrates and other granular products. Our Silotank made of imported European stainless steel has no internal competition due to:

• Excellent flow of powders and granules, due to the stainless steel surface finish. • Increased payload capacity (less tare equipment). • Download times more efficient and faster.

All these attributes led to this customer to define its purchase option and order Tersainox 5 new Silotank of 45 m3 which they will be incorporate to its fleet of equipment manufactured in stainless steel.

The use of stainless steel in the transportation industry in Chile has grown exponentially over the past 5 years. Tersainox company is leading our country in the Design and Manufacture of transport equipment in stainless steel and logistics solutions. Is committed to the development of equipment that is a contribution to the development and evolution of national transport.


SiloTank for Nitrate Transport...

Mauricio Tapia C.Transport Division.

TERSAINOX S.A.

Documents

Stainless Steel, Our Bright Ally Tank Varieties and Choice of