For a grade A metric product whose thread diameter is normally M1.4-M64, the thread tolerance is usually 6g. For a grade 12.9 product, it is 5g6g. The materials on the market are mostly grade CL8.8/10.9/12.9 carbon steels and A2-70, A4-70, A4-80 stainless steels as well as others like copper and nylon 6.6. Common surface treatment includes phosphatizing and galvanizing. In recent years, the surface coating has been upgraded due to environmental requirements, bringing out the trivalent chromium-based electroplated coating occurs and the non-electrolyzed flaky zinc coating that replaces DAC.
zinc flake, silver (ZFSHL) – This is a silver flaky zinc coating with a lubricating seal coating. Because it does not contain chromium VI, this coating can be mainly used for commercial vehicle assemblies, construction machinery, and agricultural vehicles and equipment with corrosion resistance requirements.
zinc-nickel, silver (ZNSHL) – This is a zinc-nickel alloy coating without chromium VI but with a lubricating seal coating. It has two types: black and silver, that is, ZNBHL and ZNSHL. It is mainly used in the environment with a high corrosion risk, and also decorative to some extent.
thick-film passivated (ZSML) – This is a chromium VI-free thick film passivated coating used to replace trivalent chromium, as an environmentally friendly coating and with a lubricating seal coating. This coating can better replace common galvanization such as A2C\A3C.
Other non-electrolyzed flaky zinc coatings:
GEO-Zinc-aluminium coating – Because it contains chromium VI, DAC is being replaced by GEO gradually. GEO related coatings are mainly GEO500A and GEO321 +VL.
Dimensions of DIN912 Hex Socket Screws
The following table shows the common dimensions of DIN912 hex socket screws.
Application scope of the DIN912 hex socket screws:
Because the head of a DIN912 hex socket screw can be embedded in a component, a large torque can be applied and the connection strength is high. Therefore, DIN912 hex socket screws are often used for the connecting positions with smooth appearances and compact structures required. With advantages such as easy fastening and removing and a low occurrence of slipping, they are usually used for machinery. The DIN912 hex socket screw has wide application, covering electronics, electric appliances, electrical projects, electric power, chemical industry, hydraulic projects, mechanical equipment, and furniture. Because of wide application, a large amount of DIN912 hex socket screws manufactured by Yijin Hardware are sold in a lot of European and American countries every year. Yijin Hardware has been praised by its customer from all over the world for high quality, up-to-standard dimensions and normative threads of its products. All the European and American customers say that Yijin Hardware is an excellent custom hex socket screw supplier and will always have their support!