Research on High Temperature Aging Detection Method of Heat Resistant Steel Based on Nonlinear Ultrasound Detection Technology

摘要

Rapid detection of high temperature aging process and early damage is very important for TP347HFG austenitic heat resistant steel,which is brittle and has short stable expansion period.Nonlinear ultrasound technology is sensitive to micro-nano scale defects and has great potential in early damage detection.The relationship curve between thermal damage degree and ultrasonic nonlinearity coefficient is obtained by using non-linear ultrasound technology,and the microstructure evolution characteristics of materials are analyzed.The results show that the ultrasonic nonlinearity coefficient of TP347HFG steel increases with aging time.The maximum point appears at 500 h and then increases monotonously.This trend is related to the formation and loss of conformal strain state.The experimental results provide a theoretical basis for the non-linear ultrasonic testing of TP347HFG steel at high temperature.