Annealing is a metal heat treatment process, which refers to slowly heating the metal to a certain temperature, holding it for a sufficient time, and then cooling at a suitable rate. The purpose is to reduce the hardness and improve the machinability; reduce the residual stress, stabilize the size, reduce the tendency of deformation and cracks; refine the grain, adjust the structure, and eliminate the defects of the structure. To be precise, annealing is a heat treatment process for materials, including metallic materials and non-metallic materials. And the annealing purpose of the new material is also similar to the traditional metal annealing
Generally, softening annealing of metal hose between processes must be performed. Therefore, in the SUS304 stainless steel stamping process, after being left for a period of time, the residual stress after forming is likely to cause the workpiece to explode and rupture, and the plastic index elongation rate. Due to the different degree of deformation of the material in each part of the stamping, the metal deformation resistance, strength, hardness, etc. increase with the degree of deformation, the higher the dislocation density, the more plastic the material is restored, and the workpiece will automatically generate intergranular cracking (commonly known as “Seasonal cracking”), between about 15% and 40%, is usually used as a stamping washer fastener, there is a risk of cracking or brittle fracture. When the work hardening reaches a certain level, such as continued deformation. When the distortion is larger. After the cold working of SUS 304 stainless steel hose, in order to be able to carry out the next process to eliminate residual stress, a large number of dislocations will occur on the microscopic slip surface and grain boundary, resulting in distortion of the lattice, so the degree of work hardening of the material is also different, and the section shrinkage The rate decreases, that is, intermediate annealing. Under the effect of the ambient atmosphere, the hardness of the SUS 304 stainless steel hose is reduced by deformation hardening and annealing softening.