Generally also have fingertips, coarse teeth, hardwood […]
Generally also have fingertips, coarse teeth, hardwood screws, aluminum alloy, plastic. One of the special self-tapping screws that open a metal hole cutting screw is called a "wire attack". Self-tapping screws are used for non-metal or soft metal, and do not need bottom holes and self-tapping screws. Because of the point of self-tapping screws, you can do this "self-tapping screws". Ordinary screws are flat heads with the same thickness.
Generally made of carburized steel (accounting for 99% of all products). It can also be made of stainless steel or non-ferrous metals. The product must be heat treated. Carbon steel self-tapping screws are subjected to carburizing treatment, and stainless steel self-tapping screws are subjected to solution hardening treatment. Self-tapping screws meet the required mechanical properties and performance.
The product has high surface hardness and good core toughness. "Inner and outer rigid." This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, the toughness of the core part that cannot be screwed into the substrate is poor, and the screw cannot be used after breaking. Therefore, the "internal soft outer rigid" self-tapping screws meet the requirements of performance.
The surface of the product needs surface protection treatment, usually plating treatment. The surface of some products requires phosphate treatment (phosphate). For example, wallboard self-tapping screws are mostly phosphate. Produced by cold heading technology. In order to ensure product quality, it is recommended to produce high-speed cold heading machines and high-speed massage machines or high-speed planetary roller machines. The self-tapping screws produced in this way are shaped with high thread quality.