Advantages of duplex stainless steel
Due to the high strength of Duplex steel, it is usually possible to save material, such as reducing the wall thickness of the pipe. Take the use of SAF2205 and SAF2507 as an example. SAF2205 is suitable for use in chlorine-containing environments. The material is suitable for oil refining or other process media mixed with chloride. SAF2205 is especially suitable for heat exchangers that use chlorine-containing aqueous solutions or brackish water as the cooling medium. The material is also suitable for diluted sulfuric acid solutions and pure organic acids and their mixtures. Such as: oil pipes in the oil and natural gas industry: crude oil desalination in oil refineries, sulfur-containing gas purification, wastewater treatment equipment; cooling systems that use brackish water or chlorinated solutions.
Compared with austenitic stainless steel
1) The yield strength is more than twice that of ordinary austenitic stainless steel, and it has sufficient plastic toughness for forming. The thickness of the storage tank or pressure vessel made of duplex stainless steel is 30-50% less than that of commonly used austenitic stainless steel, which is beneficial to reduce costs.
2) It has excellent resistance to stress corrosion cracking, especially in an environment containing chloride ions. Even the duplex stainless steel with the lowest alloy content has higher resistance to stress corrosion cracking than austenitic stainless steel. Stress corrosion is The outstanding problem that ordinary austenitic stainless steel is difficult to solve.
3) The corrosion resistance of the most common 2205 duplex stainless steel used in many media is better than that of ordinary 316L austenitic stainless steel, while super duplex stainless steel has extremely high corrosion resistance. In some media, such as acetic acid and formic acid It can even replace high-alloy austenitic stainless steel and even corrosion-resistant alloys.
4) It has good local corrosion resistance. Compared with austenitic stainless steel with the same alloy content, its wear resistance and corrosion fatigue resistance are better than austenitic stainless steel.
5) The coefficient of linear expansion is lower than that of austenitic stainless steel, which is close to that of carbon steel. It is suitable for connection with carbon steel and has important engineering significance, such as the production of composite plates or linings.
