Rapid evaluation technology of austenitic stainless steel material degradation

The Leeb hardness distribution, ultrasonic echo signal and microstructure of 304 stainless steel under different conditions were studied. The relationship between Leeb hardness dispersion rate, ultrasonic spectrum distribution and material degradation state was clarified. The D－S evidence theory was used to fuse multi－index information to evaluate austenitic stainless steel materials. The results show that the hardness dispersion rate of 304 stainless steel after normal solution treatment was less than 1.5%. When the material was degraded, the hardness dispersion rate would increase significantly, and the spectral energy distribution characteristics of ultrasonic echo signal also changed significantly. The D－S evidence theory was used to fuse the three indexes of Leeb hardness dispersion rate, low frequency energy drop ratio and high frequency energy drop ratio of ultrasonic echo, which could effectively solve the conflict between the evaluation indexes and significantly improve the confidence of the rapid evaluation results of austenitic stainless steel on site.