Screws with flattened half-round head hexagon socket ISO 7380-1-010.9 coated zinc flake M8x35 mm

Steel is an iron-carbon alloy with a maximum carbon content of 2% by mass. The steels achieve their intended physical and mechanical properties through various hardening, annealing and tempering processes. It is also possible to harden the edge zone by surface hardening, case hardening or nitriding. Well-known steel grades are structural steels, free-machining steels, case-hardening steels, nitriding steels, tempering steels, tool steels and stainless steels.

Zinc flake coatings are non-electrolytically applied coatings in accordance with DIN EN ISO 10683. Additional top coats and lubricants may be applied. As this is a non-electrolytic process, no hydrogen is produced which could cause the components to become brittle. This requires correct pre-treatment. The corrosion protection is 10 times greater than that provided by electroplated coatings of the same thickness.

Compared with a Phillips-head screw of the same size, a hex socket screw can withstand around ten times the torque. Hex socket screws are well suited to bolted joints where the screw heads are difficult to access due to the design of the structure. Hex socket screws can be countersunk to save space if protruding screw heads are a problem.

The number before the point multiplied by one hundred gives the nominal value of the tensile strength in N/mm2, the number before the point multiplied by the number after the point and multiplied by 10 gives the nominal value of the 0.2% yield strength in N/mm2. The number after the decimal point provides information about the yield strength, as a percentage of the tensile strength.