Stainless steels bond around a key material property: excellent corrosion resistance, attributable to high chromium content (> 10.5% by mass) and low carbon content (<1.2% by mass). Beyond the corrosion resistance, the mechanical properties of these steels can vary greatly according to the family to which they belong.
Austenitic stainless steels are the most common type of stainless steel. They are resistant to corrosion and can be easily machined and welded, although they cannot be heat treated.
Types 303 and 304 are the most common in this family, and 316L is a variant that maximizes corrosion resistance. These steels are used in a wide variety of operations, since they are weather resistant and work anywhere.
On the other hand, stainless martensitic steels offer better mechanical properties than austenitic at the cost of ductility. As a group, they lack the general versatility of austenitic steels; however, their hardness combined with a much higher corrosion resistance makes them suitable for being close to oxidizing environments.
In addition, martensitic steels can be heat treated to further increase hardness, strength and stiffness.