The most crucial aspect of fastener development and design is quality control. From incoming materials to finished product shipment, there are several key checkpoints, each with different inspection methods.
Firstly, incoming materials involve inspections of appearance, dimensions, elemental composition, performance, and hazardous substances. In-process inspections primarily focus on appearance, dimensions, impact testing, and forging flow lines. Heat treatment inspections focus on appearance, hardness, torque, tensile strength, and metallography. Surface treatment inspections primarily involve hydrogen embrittlement testing, coating testing, and salt spray testing. Shipment inspection includes hazardous substance testing.
For dimensional and appearance inspections, common instruments include 2D measuring machines, contour measuring machines, coordinate measuring machines, and image sorting machines (this is a full-selection machine). For mechanical and chemical testing, hardness testers (Rockwell and Vickers), tensile testing machines, and metallographic microscopes are used. For material testing, a spectrometer and salt spray testing machine are employed.
