Non-destructive testing method for Bolt in manufacturing process

In the bolt manufacturing process, due to the influence of factors such as raw materials, equipment, personnel and process parameters, certain defects will inevitably be caused. Due to factors such as material plasticity, deformation, mold structure, and lubrication state, defects such as surface folds, pull marks, and cracks often appear during the tanning process (cold enthalpy, heat enthalpy, stamping, etc.); Factors, the heat generated during the grinding process may not be dissipated in time, resulting in grinding burns and grinding crack defects. Cracks often appear during heat treatment due to raw material defects, irregular shape of bolts, excessive cooling rate, lack of tempering after quenching, transfer speed and other factors.

Non-destructive testing in the manufacturing process should be arranged after the process that may cause defects or expose defects, so in the manufacturing process of bolts, non-destructive testing should be arranged after the processes that may cause defects, such as tanning, cutting, heat treatment, etc. In the coating , Bolt electroplating, anodizing, bluing, phosphating and other surface treatment before. If the plating of the bolts could lead to defects such as plating cracks, non-destructive testing should be performed before and after the plating process to identify the defects.