The most important link in the development and design of fasteners is quality control. There are several major checkpoints from input to finished product shipment, and these checkpoints have different inspection methods. Firstly, there are factors related to the feeding, such as appearance, size, elements, performance, and detection of harmful substances; In terms of process, it is more about appearance, size, impact testing, and forging flow line; Heat treatment focuses more on appearance, hardness, torque, tensile strength, metallography, and so on; Surface treatment mainly involves hydrogen embrittlement testing, coating, salt spray, etc., including hazardous substance testing during shipment. In terms of size and appearance inspection, the common ones are anime, profilometer, CMM and image sorter (this is a full sorter); In terms of mechanical and chemical testing, there are mainly hardness machines (Rockwell and Vickers), tensile machines, and metallographic microscopes; In terms of material testing, there is a spectral analyzer and a salt spray testing machine
