Features of self-tapping screws

Although there are many types of self-tapping screws, they all have the following common features:
(1) They are generally made of carburized steel (accounting for 99% of the total output). They can also be made of stainless steel or non-ferrous metals.
(2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solution hardened. This allows the self-tapping screws to meet the mechanical properties and performance requirements of the standard.
(3) The product has high surface hardness and good core toughness. That is, "soft inside and hard outside". This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, it cannot be screwed into the matrix; if the core toughness is poor, it will break when screwed and cannot be used. Therefore, "soft inside and hard outside" is a very important requirement for self-tapping screws to meet performance requirements.
(4) The surface of the product needs to be treated with surface protection, generally electroplating. Some product surfaces must be treated with phosphate (phosphating), such as wall panel self-tapping screws are mostly phosphated.
(5) Produced using cold heading technology. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine for production. The emphasis on high speed here is to ensure product quality. Only the self-tapping screws produced by high-speed machines have good head formation and high thread quality.