Although many types of self-tapping screws, but they all have the following main features:
(1) are generally made of carburized steel (99% of the total product). 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, stainless steel self-tapping screws must be solid-solution hardening treatment. So that the self-tapping screws to achieve the required mechanical properties and performance.
(3) the product surface hardness, core toughness is good. That is, the soft outside just. This is a major feature of tapping screw performance requirements. If the surface hardness is low, not screw into the matrix; such as core toughness difference, a screw on the break, can not be used. Therefore, the soft outside just is the self-tapping screws to meet the performance requirements.
(4) surface protection products are required surface treatment, generally electroplating treatment. Some products are subject to phosphate treatment (phosphate). Such as: wallboard self-tapping screws are mostly phosphating.
(5) the use of cold heading process production. Recommend the use of high-speed cold heading machine and high-speed rolling machine or high-speed planetary rolling machine production to ensure product quality. This production of self-tapping screw head forming a good, high-quality thread.