Stainless Steel: The 4 Main Types

'Stainless steel' is an umbrella term that covers a range of alloys. To be considered a stainless steel an iron-based alloy must meet the single criterion of containing a minimum of 10.5% chromium. Varying this amount or adding other substances produces different types of stainless steel, each with correspondingly different properties and applications.

Generally speaking, all variations of stainless steel are divided into one of four groups. In this edition of our blog, we present a short guide to these different groups.

• AUSTENITIC. This group contains the most common types of stainless steel. Austenitic stainless steels contain, as compared to other types, a high content of nickel, chromium, molybdenum and chromium. Renowned for their high levels of malleability, strength and corrosion resistance, the austenitic steels are particularly versatile with many thousands of applications.
• FERRITIC. Carbon consistencies in ferritic stainless steel are low, usually not exceeding 0.1%. Primarily consisting of chromium but sometimes with additives such as molybdenum, ferritic stainless steels are magnetic and display excellent resistance to stress corrosion cracking. 
• DUPLEX. Essentially a combination of austenitic and ferritic stainless steels, duplex is stronger than either. It is also extremely resistant to corrosion, making it the material of choice for a number of applications in offshore oil and gas facilities.
• MARTENSITIC. Though structurally similar to ferritic stainless steel, martensitic stainless steel contains much more carbon (around 1%). This difference in carbon percentage gives rise to the key difference: martensitic stainless steels can be hardened to a massive degree, imbuing them with extremely high strength.

Our expert team here at BS Stainless can provide you with all of the information you require when it come to selecting the most appropriate type of stainless steel for any given application: simply get in touch with us for clear, authoritative advice. To stay in touch with all the latest industry news from BS Stainless, please subscribe to our newsletter and follow us on social media (facebook, twitter, linkedin).