Raised countersunk head tapping screws hexalobe ISO 14587C-stainless A2 3,5x38mm

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.

TORX (from the English word ‘torque’) is the registered word mark for a screw drive profile, the standard designation for which is ‘internal six-lobe’ (English: ‘six lobe, internal socket’). With the six-lobe internal socket, the screw and tool are subjected to less radial stress than with the traditional internal hexagon, and consequently suffer less damage. Torque is transmitted more directly via the radial parts of the tooth flanks rather than via the faces of the hexagon.

In contrast to screws, the strength class for nuts in steel only describes one key figure. This is the test stress S. It can be equated with the tensile strength Rm of the screw. Nuts with a two-digit number (e.g. 04) describe low nuts. This hexagon nut is used for screw connections with limited load capacity, e.g. as a lock nut

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.