Research on Weak Magnetic Detection Technology of Bolt Root Crack

The traditional non-destructive testing method is difficult to solve the in-service detection problem of high temperature bolt root cracks in thermal power plants. In this paper, the weak magnetic detection technology is used to detect the prefabricated artificial cracks in the root of high temperature bolts of thermal power plants by using the mesoporous passing method. The magnetic signal gradient value is calculated and detected, and the crack defect is judged by the 3σ method in probability statistics. The results show that for high temperature bolts with internal and external diameter difference of 34 mm, the high-precision magnetic sensor has a good detection effect on the root crack, and the feasibility of the weak magnetic detection technology in the in-service detection of high temperature bolt root crack is verified.