The name is not the same, but the meaning is the same. It is all self-tapping. The main function of self-tapping screws is that they do not need to be used with nuts. In terms of cost, a large number of them are saved. There is no need for a nut cost.
Key Features Although there are many types of stainless steel screws, they all have the following main features:
(1) Usually made of carburized steel (99% of the total product). It 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 screws must be solid solution hardened. So that the self-tapping screws meet the standard requirements of mechanical properties and performance.
(3) The product has a high surface hardness and a good toughness in the core. That is "inner soft outside just." This is a major feature of stainless steel screw performance requirements. If the surface hardness is low, the screw cannot be inserted into the base body; if the core has poor toughness, the screw can be cut off and cannot be used. Therefore, "inner soft outside just" is self-tapping screws to meet the performance requirements.
(4) The surface of the product needs surface protection, which is usually electroplating. Some products require phosphate treatment (phosphating). Such as: wall plate self-tapping screws are mostly phosphating.
(5) Cold heading process. It is recommended to use high-speed cold heading machines and high-speed thread rolling machines or high-speed planetary thread rolling machines to ensure product quality. The self-tapping screw head produced in this way is well formed and the thread quality is high.