(1) It is usually made of carburized steel (accounting for 99% of the total products). It can also be made of stainless steel or non-ferrous metals.
(2) It is necessary for the product to pass heat treatment. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solid solution hardened. In order to make the self-tapping screw reach the mechanical function and use function required by the standard.
(3) The product has high surface hardness and good core resistance. That is "soft inside and rigid outside." This is a major feature of the self-tapping screw function request. If the surface hardness is low, it cannot be screwed into the matrix; if the core has poor resistance, it will break once screwed, and it cannot be used. Therefore, "flexible inside and rigid outside" is a request for satisfactory use of self-tapping screws.
(4) The appearance of the product requires appearance protection treatment, usually electroplating treatment. The appearance of some commodities needs to be treated with phosphate (phosphating). For example, self-tapping screws for wall panels are mostly phosphated.
(5) Produced with cold heading technology. It is recommended to select high-speed cold heading machines and high-speed thread rolling machines or high-speed planetary thread rolling machines to ensure the quality of goods. The head of the self-tapping screw produced in this way is well formed and the thread quality is high.
