Crack propagation acoustic emission characteristic signal detection method for weld joint

Abstract

The invention relates to a crack propagation acoustic emission characteristic signal detection method for a weld joint. The detection method comprises the following steps of preparing a spare part compact tensile sample; carrying out a tensile experiment on the spare part compact tensile sample, and detecting vibration and friction acoustic emission characteristic signals of a tensile experiment machine in the tensile process to obtain an interference characteristic signal curve in a crack propagation acoustic emission test of the weld joint; preparing a compact tensile sample; setting a signal acquisition threshold value of acoustic emission detection software according to the interference signal characteristic curve of the spare part compact tensile sample; performing a tensile experiment on the compact tensile sample, and detecting an acoustic emission characteristic signal of precrack source expansion in the tensile process to obtain a characteristic curve of a weld crack expansionacoustic emission signal; after the tensile experiment, the compact tensile sample being subjected to fatigue breaking; and judging the fracture crack propagation characteristic morphology of the compact tensile sample. The method is advantaged in that acoustic emission detection accuracy of the pressure vessel can be improved.

Description

technical field [0001] The patent of the present invention relates to a crack propagation acoustic emission detection method of welds, in particular to a detection method of crack propagation acoustic emission characteristic signals in different weld regions. Background technique [0002] Pressure vessels are widely used in power generation, petroleum, chemical industry, machinery, power, metallurgy, nuclear energy and other industries. Commonly used pressure vessels include steam generators, deaerators, cylinders, heat exchangers, etc. In the pressure vessel manufacturing process, welding plays an indispensable role and is an important process in the final forming of the pressure vessel. Therefore, the stability of the welded structure is a key factor that determines whether the pressure vessel can be used stably for a long time. In the common failure of pressure vessel equipment, the crack propagation of welded structure is a hidden danger in the safe service of pressure v...

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Problems solved by technology

[0003] Crack growth in welded structures often goes through three stages: nucleation, stable growth, and unstable growth. Once the crack growth enters the unstable growth, it will cause irreversible damage to the material, which is extremely harmful, and the crack growth reduces the load-carrying capacity of the welded structure. , may promote the ductile-brittle transition fracture of the pressure vessel

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