Super Stainless Steel

Super stainless steel is a special stainless steel. First of all, it is different from ordinary stainless steel 304 in chemical composition, which refers to a high alloy stainless steel containing high nickel, high chromium and high molybdenum. Secondly, in terms of high temperature resistance or corrosion resistance, compared with 304, it has more excellent high temperature resistance or corrosion resistance, which is irreplaceable by 304. In addition, from the classification of stainless steel, the metallographic structure of special stainless steel is a stable austenitic metallographic structure. These Super Stainless Steel alloys find applications in a wide range of industries, including aerospace, chemical processing, power generation, automotive, and medical devices, where high performance and reliability are essential.

Due to the low carbon content of super martensite stainless steel, it is equivalent to increasing the proportion of chromium content in the matrix metal, so it has good corrosion resistance. For weak acid corrosion environment, super martensite stainless steel has a tendency to replace other corrosion resistant alloys. However, under the corrosion conditions of high temperature and the presence of carbon dioxide, general corrosion and local corrosion will occur. Under the corrosion conditions of carbon dioxide and hydrogen sulfide, stress corrosion cracks generated at room temperature and local corrosion and general corrosion generated at high temperature must be considered. According to the different corrosion conditions (such as CO2 or CO2+H2S), different grades of super martensite stainless steel (with or without molybdenum) have been developed.

The concept of super austenitic stainless steel appeared together with super ferritic stainless steel and super duplex stainless steel. Typical examples are super austenitic stainless steels containing 6% Mo and 7% Mo. These steels are developed for industries with harsh working conditions, such as petrochemical, chemical, paper and offshore systems.

Examples of super stainless steel alloys include:

● Duplex stainless steels (e.g., SAF 2205, SAF 2507)
● Super duplex stainless steels (e.g., Zeron 100, Ferralium 255)
● Precipitation-hardening stainless steels (e.g., 17-4 PH, 15-5 PH)
● Nickel-based superalloys (e.g., Inconel, Hastelloy)