Classes of Stainless Steel

Stainless steel has always remained a popular iron alloy used in a number of industries, owing to the benefits it offers. Not only is it corrosion resistant but also requires very low maintenance. What lends the stainless steel an amazing corrosion resistant property is the presence of chromium, while other elements such as nickel, molybdenum, and nitrogen are responsible for other amazing properties that stainless steel has in store. It is divided into 5 different classes with each identified by particular alloying elements that affect their microstructure -

1. Martensitic stainless steel
2. Austenitic stainless steel
3. Precipitation-Hardening (PH) stainless steel
4. Ferritic stainless steel
5. Duplex (ferritic-austenitic) stainless steel

Martensitic Stainless Steel

Martensitic Stainless grades are chromium steels and don’t have any nickel in it. These belong to a group of stainless alloys that are corrosion resistant and can be hardened even further using heat treatment. In materials where hardness and wear resistance is necessary, steel roofing sheets, for instance, martensitic stainless steel is usually preferred.  

Austenitic Stainless Steel   

This is the most widely used stainless class. Austenitic stainless steel grades have high chromium and nickel content which lend it a superior corrosion resistance along with excellent mechanical properties. While heat treatment might not help harden it, cold-working can definitely do. These grades are non-magnetic in nature.

Precipitation-Hardening (PH) Stainless Steels

Precipitation hardening stainless steel has an amazing strength and fabric-ability. Moreover, it offers unsurpassed corrosion resistance and ease of heat treatment. It can be hardened and strengthened using heat treatment.   

Ferritic Stainless Steel

Along with being stress and crack resistant, ferritic stainless steel grades are also corrosion and oxidation resistant. These grades are magnetic and are made up of chromium steel without any nickel in it.  They are often used in sinks, decorative trims, exhaust systems etc. Also, they have a higher corrosion resistance as compared to martensitic grades.

Duplex (Ferritic-Austenitic) Stainless Steel

Duplex grades are a blend of ferritic and austenitic material. If we talk about strength, these grades are double strong as compared to ferritic and austenitic grades. Although they are more tough and ductile than the ferritic grades, they simply cannot match the level of austenitic grades. The most commonly used duplex class is grade 2205. Do note that the metal sheet proofing price in India depends on the type of steel and grade being used in its manufacturing.