There are two subgroups of austenitic stainless steel: 300 and 200. While 300 series stainless steels achieve their austenitic structure primarily by a nickel addition, 200 series stainless steels substitute manganese and nitrogen for nickel (although there is still a small nickel content).
The Austenitic Formula
Austenitic stainless steels contain a significant amount of chromium, and sufficient nickel or manganese to “stabilise” the austenite micro-structure that gives these steels good formability and ductility (and makes them non-magnetic). A typical composition is 18% chromium and about 8% nickel, as found in the popular 304 grade. Some 300 series stainless steels, such as the 316 grade, also contain molybdenum. This increases the material’s resistance to acids, pitting and crevice corrosion.
All austenitic grades can be highly durable and corrosion resistant and have high ductility, low yield stress, relatively high tensile strength and good weldability. As such, they have a very wide range of uses.
Adding nickel is the classic way of preserving an austenitic structure in stainless steel. However, adding manganese, combined with nitrogen, can have the same effect – and at lower material cost.
Chrome-manganese grades are characterised by having a considerably reduced nickel content. They also see the addition of manganese and, often times, nitrogen and copper too. This reduced nickel content reduces the maximum content possible in the alloy. However, less chromium means less corrosion resistance, thus limiting the types of applications that this stainless steel can be used for.
Not only are chrome-manganese stainless steels significantly cheaper from a material cost point-of-view, depending on their chemical composition, they also offer good formability (ductility) and/or strength.
- Highly durable
- Corrosion resistant
- High ductility
- Low yield stress
- Relatively high tensile strength
- Good weldability
- Wide range of uses
- Rail transport: body of dry bulk wagon, tank for liquids, passenger wagon cladding
- Container shells
- Tankers: shell and tank bottom, cladding/outer skin
- Food processing: milk cooler (shell and tank bottom), beer keg
- Chemical industry
- Industrial applications
The construction and interior design sectors demand innovative, durable and aesthetic solutions – and stainless steel fits the bill.
To meet this demand, Aperam has a range of engraved, or textured, stainless steel products. But these textures offer more than just an aesthetical touch. They also enhance the material’s durability, making it the perfect solution for such high-use applications as the inside of an elevator or a subway station.
for Every Application
Ready to start working on a tailor-made solution backed by an industry-leading commitment to long-term support? Our experts are standing by and ready to help you choose the right Aperam products for your specific needs.