Hammer-head screws type 28/15 stainless A2 M10x80

Austenitic stainless steels derive their different strength grades from cold working to varying degrees. The number 80 following the grade designation indicates the tensile strength as one-tenth for bolts. A bolt in strength class 70 therefore has a tensile strength of 700 N/mm². For nuts, the number 70 indicates a stress under test load of 700 N/mm².

Stainless steel refers to alloyed or unalloyed steels that contain at least 10.5% chromium and less than 1.2% carbon. Colloquially, stainless steel is also referred to as stainless steel (NiRo), although not all stainless steel is the same as "stainless".

Stainless steels are defined in DIN EN 10088-1 as iron alloys containing at least 10.5 per cent chromium and no more than 1.2 per cent carbon. The multi-part DIN EN ISO 3506 series of standards applies to mechanical fasteners made from stainless steels. Grade A2 is classified as non-acid-resistant. Austenitic stainless steels cannot be heat-treated and achieve their different strength classes through cold working to varying degrees.