Disc springs EN 16983-spring steel 18,3x35,5x2,0 mm

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".

The term plain indicates a completely untreated, merely oiled, smooth surface for all DIN and ISO screws such as wood screws, hexagon head screws, threaded rods, nuts and many types of washers.

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. Special austenitic stainless steel grades include 1.4615, 1.4310, 1.4980, 1.4986, 1.4539, 1.4841, 1.4828, 1.4845, 1.4020 and 1.4378. Austenitic stainless steels cannot be heat-treated and achieve their different strength classes through cold working to varying degrees.