No-destructive testing method and no-destructive testing device for creep cavity damage of igh chromium martensitic heat-resistant steel joint

Abstract

The invention provides a no-destructive testing method and a no-destructive testing device for creep cavity damage of a high chromium martensitic heat-resistant steel joint. The detection difficult problem of the creep cavity damage of a novel high chromium martensitic heat-resistant steel joint is solved by adopting a nonlinear ultrasonic technology. The damage degree of the joint is evaluated byusing high-order harmonics generated by interaction between high-energy radio frequency pulse and micro defects inside a material. According to the no-destructive testing method disclosed by the invention, the high-temperature creep damage degree of the high chromium martensitic heat-resistant steel joint is detected by using a nonlinear ultrasonic technology, and the quantitative relation between a creep cavity and nonlinear ultrasonic parameters is established, so that the quantitative evaluation of the creep cavity damage during the service of the novel high chromium martensitic heat-resistant steel joint is realized and further long-term safe operation of an ultra-thermal power unit is ensured.

Description

technical field [0001] The invention belongs to the field of metal material detection, and in particular relates to a method and a device for detecting creep hole damage of high-chromium martensitic heat-resistant steel joints. Background technique [0002] New high-chromium martensitic heat-resistant steels such as T / P91, T / P92, T / P122 and T / P911 have good thermophysical properties, thermal fatigue resistance, especially excellent high-temperature creep properties, and are ideal for manufacturing super Ideal material for main steam pipes, headers and heating surface pipes of supercritical units. However, the welded joints of this type of steel have a serious tendency of type IV creep fracture during service, which significantly reduces the high-temperature creep strength and fracture life of the joint, leading to early failure of components. Type IV creep fracture is a kind of extremely harmful brittle fracture, which is likely to cause major safety accidents. Type IV fra...

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Problems solved by technology

[0003] In the process of type IV creep rupture, the hole first occurs in the center of the joint, so it cannot be found by surface coating metallurgy and other detection methods

Traditional linear ultrasonic testing techniques (such as longitudinal wave sound velocity method and attenuation method) are only sensitive to volumetric defects and open cracks, and can only detect macroscopic cracks formed at the end of the creep life of joints, and it is difficult to detect creep that occurs in the early and middle stages hole, so timely warning cannot be achieved

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