Oval-head drill screws hexalobe DIN 7504M-stainless C1 1.4006 3,5x25 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.

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.

The material 1.4006 or X12Cr13 is a martensitic stainless chromium steel. Other designations for this material include: AISI 410, BS 410S21, SIS 2302, amongst others. Owing to its good corrosion resistance, it is used in the manufacture of pumps and in hydraulic engineering, as well as for decorative purposes, e.g. in kitchen fittings. Other areas of application include the food industry, environmental engineering and energy technology.

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 of stainless steels. C1 has low impact strength and ductility. Caution is advised when using C1 at temperatures below freezing. Martensitic steel grades are always highly magnetic.