Project Description

F61 /2205 (UNS S32550)

Super Duplex Stainless Steel. High performance 25% chromium super duplex (austenitic/ferritic) steel with 1.75% copper. Good strength/ductility combinedwith high resistance to all forms of corrosion. For Oil & Gas, defence, nuclear, chemical/ petrochemical and marine applications.

* Specification

Bar, Rod, WireASTM A182
ForgingASTM A182
Pipe, TubeASTM A789
Plate, Sheet, StripASTM A167, 240
OtherASTM A403

* Chemical Composition, %


* Feature

  • Compared with austenitic stainless steel
  1. Yield strength is more than twice as high as that of common austenitic stainless steel, and it has enough plasticity and toughness for forming. The thickness of tanks or pressure vessels made of duplex stainless steel is 30-50% less than that of common austenitic stainless steel, which is conducive to reducing costs.
  2. It has excellent stress corrosion cracking resistance, especially in the environment containing chloride ions. Even duplex stainless steel with the lowest alloy content has higher stress corrosion cracking resistance than austenitic stainless steel. Stress corrosion is a prominent problem that ordinary austenitic stainless steel is difficult to solve.
  3. In many media, the corrosion resistance of 2205 duplex stainless steel is better than 316L austenitic stainless steel. Super duplex stainless steel has very high corrosion resistance. In some media, such as acetic acid, formic acid and so on, it can even replace high alloy austenitic stainless steel, even corrosion resistant alloy.
  4. It has good local corrosion resistance. Compared with Austenitic stainless steel with the same alloy content, its wear resistance and corrosion fatigue properties are better than those of austenitic stainless steel.
  5. The linear expansion coefficient of austenitic stainless steel is lower than that of austenitic stainless steel, which is close to that of carbon steel. It is suitable for joining with carbon steel and has important engineering significance, such as producing composite plates or linings.
  • Compared with ferritic stainless steel, duplex stainless steel has the following advantages:
  1. The comprehensive mechanical properties are higher than those of ferritic stainless steel, especially the plasticity and toughness. It is not as sensitive to brittleness as ferritic stainless steel.
  2. Except the stress corrosion resistance, the local corrosion resistance of ferritic stainless steel is better than that of ferritic stainless steel.
  3. The cold working process and cold forming properties are much better than those of ferritic stainless steel.
  4. Welding performance is much better than that of ferritic stainless steel. Generally, there is no need for preheating before welding and no need for heat treatment after welding.
  5. The application range is wider than that of ferritic stainless steel.

* Application

It is suitable for chlorine-containing environment, and this material is suitable for oil refining or other process media mixed with chloride. It is especially suitable for heat exchangers using chlorine-containing water or brackish water as cooling medium. The material is also suitable for diluted sulfuric acid solutions, pure organic acids and their mixtures. Such as: oil pipelines in oil and gas industry; desalination of crude oil in refineries, purification of sulphur-containing gases, waste water treatment equipment; cooling system using brackish water or chlorine-containing solution.