Stainless Steels

Austenitic Stainless Steels

Austenitic stainless steels are the most commonly used grades of stainless steel. They provide predictable levels of corrosion resistance, high ductility and excellent mechanical properties. This class of stainless steel derives its name from its microstructure, which is primarily austenitic at room temperature. The austenitic structure is a face-centred cubic (FCC) crystal lattice and it is characterized by its stable, non-magnetic nature.

Properties

Not only recognised for their non-magnetic nature, the completely austenitic grain structure means that they are extremely formable, readily welded and retain their ductility down to cryogenic temperatures. They can also be used at raised temperatures, as they retain more of their strength in comparison with ferritic alloys.

They can be significantly strengthened by cold working, but this work-hardening effect also means that machining may need to be undertaken more carefully. Larger section sizes can be strengthened by warm working. As a wholly austenitic structure, heat treatment has no effect.

Grades of Austenitic Steel

The range of Fermonic^® 50 grades (also known as Nitronic^® 50 – a trademark of AK Steel Corporation) provides more than double the strength of Alloy 316L for instance, benefiting from controlled nitrogen additions to strengthen the austenitic structure. Higher strength allows section sizes to be reduced, whilst retaining the favourable characteristics of austenitic grades in general.

The Fermonic^® 60 product (also known as Nitronic^® 60 – a trademark of AK Steel Corporation) is more specialised – it has superior galling resistance resulting from additions of manganese and silicon, making it preferable for applications where there is repeated movement/sliding or frequent assembly/disassembly.

Applications

Good corrosion resistance is imparted by 16-25% Cr additions, but can be significantly improved by further additions. For instance, Alloy 316L benefits from the addition of molybdenum to improve resistance to pitting and crevice corrosion in chloride environments.

Alloy 254 contains even greater levels of molybdenum to further enhance corrosion resistance in aggressive environments, making it suited to brackish or polluted water contact, or in applications containing halide ions (chloride, bromide, fluoride) where it can be a cost-effective alternative to more expensive nickel and titanium alloys in such environments.

Austenitic Stainless Steels From Langley Alloys

For more information on any of the austenitic stainless steel grades from Langley Alloys, you can view our summary tables below. Alternatively, you can click on them separately, download the PDF and request a quote. For other enquiries, contact us today, our expert team will be happy to assist you.