Super duplex stainless steel is a novel alloy with a mixed microstructure of austenite and ferrite. This two-phase microstructure is derivative of duplex stainless steel, which is ideally engineered to a ratio of 50:50. Achieving this fine microstructural balance enables the fabrication of a stainless steel grade that exceeds the mechanical properties of each individual type. It can also resolve many of the perceived drawbacks of both austenitic and ferritic stainless steel grades.
In this blog post, Masteel will explore super duplex stainless steel in more detail.
Outlining Super Duplex Stainless Steel
Super duplex stainless steel is differentiated from standard duplex grades by its significantly improved corrosion-resistant properties. It is a highly alloyed material with elevated concentrations of anti-corrosive elements such as chromium (Cr) and molybdenum (Mo). The primary super duplex stainless steel grade, S32750, comprises as much as 28.0% chromium, 3.5% molybdenum, and 8.0% nickel (Ni). These components impart exceptional resistance to corrosive agents, including acids, chlorides, and caustic solutions.
Generally, super duplex stainless steels build upon the established benefits of duplex grades with enhanced chemical stability. This makes it an ideal grade for fabricating critical components in the petrochemical sector, such as heat exchangers, boilers, and pressure vessel equipment.
It is also stronger in the lateral plane and boasts a greater yield strength, with good ductility and toughness to suit various forming methods. Typically, super duplex stainless steel is cheaper to produce than high-nickel austenitic grades that are engineered to resist galvanic corrosion and pitting corrosion in marine environments.
Stainless Steel Grades from Masteel
Masteel is one of the world’s largest suppliers of super duplex stainless steel grade S32750, with an excellent tensile strength of 620 MPa and a good Brinell hardness rating of 293. It has been used in a number of facets in the oil and gas industry and has proven useful in offshore engineering.
If you would like to learn more about the various stainless steel grades available from Masteel, browse our previous blog posts:
- Outlining Ferritic Stainless Steel
- Outlining Austenitic Stainless Steel
- What is Martensitic Stainless Steel?