Stainless steel

Stainless steels are steels containing at least 10.5% chromium and no more than 1.2% carbon. Stainless steels are subdivided according to their main properties into corrosion-resistant steels, heat-resistant steels and creep-resistant steels.

A corrosion-resistant steel is a steel with good resistance to local or uniform environmental attack. Protection is provided by a spontaneously formed chromium oxide layer.

The microstructure of these stainless steels will have a major effect on its properties. There are three main types of microstructure: ferritic steels, martensitic steels and austenitic steels.

FERRITIC STEELS

Ferritic steels have low weldability due to their susceptibility to intergranular corrosion and embrittlement in the heat-affected zone. They are mainly used for applications requiring corrosion resistance but not high mechanical strength.

MARTENSITICS

Martensitic steels have high strength, are magnetic and are difficult to weld. There are so-called super martensitic steels that combine high strength with good toughness and weldability. They are mainly used for hardened applications to obtain very high mechanical strength.

AUSTENITIC STEELS

Austenitic steels are non-magnetic and are ductile over a wide temperature range from cryogenic to creep temperatures. They have no brittleness range. Their mechanical strength is high at low temperatures. By cold deformation, they can be cold worked to high levels of strength.