Duplex Stainless Steel Casting

What is Duplex Stainless Steel Casting ?Duplex Stainless Steel Casting is the casting process which use duplex stainless steel as the raw material.It is stainless steel casting which is made from a mix of 50% : 50% austenitic and ferritic phases. So it is known as austenitic-ferritic stainless steel casting.This grade casting offers a combination of higher strengths and good corrosion resistance. Especially in sea water environment applications. At same time,these alloys also offer good toughness at lower temperatures. Its higher strengths provide erosion resistance.

  Duplex stainless steel is called “duplex” because they have a two-phase microstructure consisting of grains of ferritic and austenitic stainless steel. The picture shows the white austenitic phase as “islands” surrounded by the grey ferritic phase. When duplex stainless steel is melted it solidifies from the liquid phase to a completely ferritic structure. As the material cools to room temperature, about half of the ferritic grains transform to austenitic grains (“islands”). The result is a microstructure of roughly 50% austenite and 50% ferrite.

Duplex-Stainless-Steel-microstructure

Duplex stainless steel has Duplex and super Duplex stainless steel different.

  By combining the best aspects of both ferritic and austenitic stainless steels, duplex steels offer high strength and great corrosion resistance, such as resistance to stress corrosion cracking.

  Super duplex castings are more complex, and more highly alloyed than duplex castings. They offer even higher strength and resistance to corrosion. So they are suitable for extremely demanding applications. This kind of casting meets the demands of tough environments. Such as desalination plants, and is used in the oil and gas industries.

Characters of Duplex Stainless Steel Casting

Strength Duplex stainless steel castings are about twice as strong as regular austenitic or ferritic stainless steel castings
Toughness and ductility Duplex stainless steel castings have significantly better toughness and ductility than ferritic stainless steel castings. However, they do not reach the excellent values of austenitic stainless steel castings.
Corrosion resistance As with all stainless steels, corrosion resistance depends mostly on the composition of the stainless steel castings. For chloride pitting and crevice corrosion resistance, their chromium, molybdenum and nitrogen content are most important. Duplex stainless steel casting grades have a range of corrosion resistance, similar to the range for austenitic stainless steel castings. I.E. from Type 304 or 316 to 6% molybdenum stainless steel castings.
Stress corrosion cracking resistance Duplex stainless steels show very good stress corrosion cracking resistance, a property they have “inherited” from the ferritic side. Stress corrosion cracking can be a problem under certain circumstances (chlorides, humidity, elevated temperature) for standard austenitic castings. Such as Types 304 and 316 stainless steel castings.
Cost Duplex stainless steel castings have lower nickel and molybdenum contents than their austenitic counterparts of similar corrosion resistance. Due to the lower alloying content, duplex stainless steels can be lower in cost, especially in times of high alloy surcharges. Additionally, it may often be possible to reduce the section thickness of duplex stainless steel, due to its increased yield strength compared to austenitic stainless steel. The combination can lead to significant cost and weight savings compared to a solution in austenitic stainless steels.

The Typical representative of Duplex Stainless Steel Casting is 2205 Grade

2205 Duplex Stainless Steel Casting

  Duplex 2205 Stainless Steel is a nitrogen-enhanced duplex stainless steel casting process. It mainly used for applications requiring high strength and excellent corrosion resistance. It is combined to improve resistance to stress corrosion cracking, pitting and crevice corrosion. Duplex 2205 Stainless Steel Castings provide nearly double corrosion resistance performance in other austenitic stainless steels.

Duplex Stainless Steel 2205 Chemical Composition

CompositionContent
C 0.03 Max
Mn 2 Max
Si1 Max
P0.03 Max
S0.02 Max
Cr22.0-23.0
Mo3.0-3.5
Ni4.5-6.5
N0.14-0.20

2205 duplex stainless steel castings applications:

Food processing equipment
Marine Boat Equipment
Chemical process vessels, heat exchangers and piping
Oil field piping and heat exchangers
Bleach washers, chip pre-steaming vessels and pulp mill digesters
Glass fittings and Glass Spigot

Douplex Stainless Steel Castings Foundry

  We manufacture a wide range of super duplex stainless steel castings. We are specialized in the customized production of duplex stainless steel castings and OEM.Our manufacturing capability of duplex stainless steel casting weight ranges from 1g to 50kgs. The minimum wall thickness is 1.6mm.

  We have a stainless steel foundry fully equipped and machining factory.They ensure the qualified finished products each time. Beside stainless steel castings manufacturing, we also offer sand molding,chemical analysis, heat treatment,CNC Machining and many other value added services. From samples, drawings and customer-supplied patterns,even we can organise pattern-making and the machining of castings. Once you placed order to us, the rest weok will be done by our team.