Due to the characteristics of the two-phase organization, through the proper control of chemical composition and heat treatment process, DSS combines the advantages of ferritic stainless steel and austenitic stainless steel.
Duplex stainless steel features:
1, Compared with the austenitic stainless steel, duplex stainless steel advantages are as follows: (1) Yield strength is more than twice as high as that of ordinary austenitic stainless steel and has sufficient plastic toughness required for molding. The use of duplex stainless steel to produce tanks or pressure vessel wall thickness than the commonly used austenite to reduce 30-50%, is conducive to reducing costs. (2) It has excellent resistance to stress corrosion cracking, even with the lowest amount of duplex stainless steel also has a higher resistance to corrosion than austenitic stainless steel, especially in chloride ion environment. Stress corrosion is a prominent problem that ordinary austenitic stainless steel is difficult to solve. (3) The most common use of 2205 duplex stainless steel corrosion resistance is better than ordinary 316L austenitic stainless steel, and super duplex stainless steel has a high corrosion resistance, and then some media, such as acetic acid, Formic acid, etc. can even replace the high alloy austenitic stainless steel, the ball net and even corrosion resistant alloy. (4) It has good resistance to local corrosion, compared with the alloy content of austenitic stainless steel, its wear resistance corrosion and fatigue corrosion resistance is better than austenitic stainless steel. (5) Than the austenitic stainless steel linear expansion coefficient, and carbon steel close to, suitable for connection with carbon steel, has important engineering significance, such as the production of composite panels or lining. (6) Both in the dynamic or static load conditions, than the austenitic stainless steel has a higher energy absorption capacity, which structural parts to deal with emergencies such as collision, explosion, etc., double-phase stainless steel has obvious advantages, practical application value.
Compared with austenitic stainless steel, the weakness of duplex stainless steel is as follows: (1) The application of universal and multi-faceted as austenitic stainless steel, for example, its use temperature must be controlled at 250 below. (2) Its plastic toughness than austenitic stainless steel low, cold, hot processing technology and forming performance as austenitic stainless steel. (3) The existence of the temperature brittle area, the need for strict control of heat treatment and welding process system to avoid the emergence of harmful phase, damage performance.
2, Compared with ferritic stainless steel, duplex stainless steel advantages are as follows: (1) Comprehensive mechanical properties than ferritic stainless steel is good, especially plastic toughness, not as ferritic stainless steel as brittle sensitive. (2) In addition to stress corrosion resistance, the other resistance to local corrosion is better than ferrite stainless steel. (3) Cold processing technology and cold forming performance is much better than ferrite stainless steel. (4) Welding performance is far better than ferritic stainless steel, the general welding without preheating, after welding without heat treatment. (5) Wide range of applications than ferritic stainless steel.