A test method for residual stress of heat-resistant steel pipes for ultra-supercritical boilers

Abstract

The invention relates to a residual stress test method for a heat-resistant steel tube used for an ultra-supercritical boiler. The residual stress test method comprises the following steps that a coupling device is arranged by using a transmitting polarization wave probe, and the coupling device can be coupled with the external surface of the steel tube and the probe can be firmly fixed; and ultrasonic incident waves with frequency F are introduced to the surface of the steel tube, the excitation angle of the ultrasonic incident waves is adjusted, the amplitude of incident and emergent waves is measured by using a detector, and residual stress is determined through reckoning according to incident time, emergent time and the frequency / wavelength, wherein the heat-resistant steel tube is an austenitic heat-resistant steel tube, and the ultrasonic frequency F is 51-54MHz. Lossless determination suitable for the steel tube with curvature can be performed by the method.

Description

technical field [0001] The invention relates to a method for residual stress, in particular to a method for testing residual stress of heat-resistant steel pipes for ultra-supercritical boilers. Background technique [0002] A supercritical boiler refers to a boiler whose outlet steam pressure is greater than the critical pressure of water, 22.1MPa, and whose operating temperature is higher than the critical temperature of water, 374°C. The ultra-supercritical boiler is a new type of boiler that uses higher pressure and temperature to improve the thermal efficiency of operation based on the supercritical boiler. For the definition of ultra-supercritical boilers, there is no unified delineation in the current world power industry. It is generally considered that boilers with steam pressure higher than 26MPa and steam temperature higher than 590°C are ultra-supercritical boilers. Austenitic heat-resistant steel pipes have attracted widespread attention for their high-temperat...

AI Technical Summary

Problems solved by technology

The traditional method of ultrasonic testing of plates and other planes is not suitable for measuring steel pipes, let alone austenitic heat-resistant steel pipes

[0006] However, in the prior art, ultrasonic waves have not been used to test the residual stress of heat-resistant steel pipes for ultra-supercritical boilers, especially for austenitic heat-resistant steel pipes.