|
As the two-phase characteristics of the composition, through proper control of chemical composition and heat treatment process, so that it could get advantages of ferritic stainless steel and austenitic stainless steel.
Compared with the austenitic stainless steel, duplex stainless steel has the following advantages:
1) The yield strength of it is more than twice compared with conventional austenitic stainless steel, and it has adequate toughness to meet with molding needs. Wall thickness of storage tank or pressure vessel which is made of duplex stainless steel is less than the usual 30-50% compared with austenite stainless steel. It is beneficial to reduce costs;
2) It has excellent capacity of stress corrosion and cracking resistance, even duplex stainless steel with the lowest alloy has superior capacity of stress corrosion and cracking resistance compared with the austenitic stainless steel, especially in the environment of chloride ions. Stress corrosion is a outstanding problem of common austenitic stainless steel and it is difficult to resolve.
3) 2205 duplex stainless steel is the most common applied in many medium and it has superior corrosion resistance than the average of 316L stainless steel, the super-double duplex stainless steel has excellent corrosion resistance. In some medium, such as acetic acid, formic acid, etc, it can even replace the high-alloy austenitic stainless steel as well as corrosion resistant alloy.
4) It has a good localized corrosion resistance property. Compared with the quite alloy content of austenitic stainless steel, it has superior wear corrosion resistance and fatigue resistance compared with the austenitic stainless steel.
5)The linear expansion coefficient of 2205 stainless steel is lower than austenitic stainless steel and close to carbon steel, it is suitable to connect with carbon steel and has engineering significance, such as the production of composite board or lining etc.
6) Whether in static or dynamic loading conditions, it has a higher energy absorption capacity than austenitic stainless steel. Duplex stainless steel has obvious advantages of dealing with incidents, such as collisions, explosions, etc, and it has practical value.
Compared with the austenitic stainless steel, duplex stainless steel has disadvantages as follows:
1) Duplex stainless steel, the application of universal and multi-faceted are not as good as austenitic stainless steel, for example, temperature of it must be controlled below 250 degrees Celsius;
2) The plasticity and toughness is lower than the austenitic stainless steel, cold processing , heat processing and molding properties is not as good as austenitic stainless steel;
3) In the brittle temperature zone, it must be strictly controlled of heat treatment and welding technology system in order to avoid the appearance of harmful phase, damage property.
Compared with the ferritic stainless steel, duplex stainless steel has the following advantages:
1)The comprehensive mechanics properties of it is better than ferritic stainless steel, especially the plastic toughness, it is not as brittle sensitive as ferritic stainless steel;
2) Unless the stress corrosion resistence, other ocalized corrosion resistance is superior to ferritic stainless steel.
3) The properties of cold processing and cold forming are far superior to ferritic stainless steel;
4) Welding property is also far superior to ferritic stainless steel, the former general used of welding is without preheating and without heat treatment after welding;
5) The scope of application is wider than ferritic stainless steel.
Compared with the ferritic stainless steel, duplex stainless steel disadvantages are as follows:
1) The high content of alloying elements, the price is relatively high, generally free of nickel ferrite.
|
News 
