Nondestructive evaluation method of stress of cladding layer based on critical refraction longitudinal wave

Abstract

The invention relates to the stress evaluation of a laser cladding layer and in particular relates to a nondestructive evaluation method of the stress of a cladding layer based on a critical refraction longitudinal wave. According to the invention, the nondestructive evaluation of the cladding layer stress is realized through selecting a double critical refraction longitudinal wave probe with a suitable central frequency; an optimum propagation distance is determined as the spacing distance between a propagation probe and a receiving probe to be fixed by combining the law that the energy of the critical refraction longitudinal wave in the cladding layer decays; the time difference between the critical refraction longitudinal signals is used for representing the change amount of the propagation speed of the cladding layer in the critical refraction longitudinal wave caused by the stress and taken as the characteristic parameter to evaluate the stress of the cladding layer to build a stress-time difference relation; a liner function is adopted to fit results to obtain an acoustoelastic equation used for representing the stress of the cladding layer, and therefore the nondestructive evaluation of the stress of the cladding layer based on the critical refraction longitudinal wave is realized.

Description

technical field [0001] The invention relates to stress evaluation of laser cladding layers, in particular to a method for non-destructive evaluation of cladding layer stress based on critical refraction longitudinal waves. Background technique [0002] In the industrial field (especially the heavy industry field), the failure of key components may directly or indirectly lead to the overall failure of mechanical equipment. For this reason, a large number of steel machinery and equipment are recycled in the form of scrap steel in my country every year, and are used as primary materials for refurbishment. This not only results in the waste of resources and energy, but also seriously pollutes the environment; based on the requirements of sustainable development of resources, environment and society, remanufacturing of failed steel parts can not only reduce industrial production costs, but also improve production efficiency , reduce environmental pollution, realize energy saving an...

AI Technical Summary

Problems solved by technology

[0003] Based on the failure analysis of waste parts, preparing remanufactured coatings with corresponding properties on the surface is an effective measure to improve the surface performance of parts and prolong their service life; laser cladding technology has the advantages of concentrated energy density, high cladding efficiency, and the Forming excellent metallurgical bonding interface, small heat-affected zone and other advantages, so it has received a lot of attention and widely used in the field of remanufacturing; research shows that the quality of laser cladding layer is the key factor that affects or even determines the quality of laser cladding remanufacturing products, and stress (especially residual stress) is a key factor affecting the quality of the laser cladding layer. Therefore, evaluating the stress of the laser cladding layer is not only of great significance to ensure the quality of laser cladding remanufacturing products, but also to promote the smoothness of the remanufacturing project. Development is also of great significance; at present, stress evaluation methods are mainly two categories: lossy method (bending method, small hole method, etc.) and nondestructive method (ray method, optical method, etc.), although the above methods can be realized to a certain extent However, there are certain problems in the evaluation of cladding layer stress. For example, the bending method needs to destroy the integrity and performance of the sample, and it is a sampling test, so the results are somewhat accidental; the ray method has radiation, which seriously endangers the health of operators. Moreover, the detection equipment is expensive and not suitable for on-site and real-time detection; the optical method has high requirements on the operating environment and requires professional operators to operate, and its popularization and application are relatively limited; critically refracted longitudinal waves belong to the category of ultrasonic waves, and this method has non-destructive, Fast, safe operation, suitable for on-site detection and online monitoring, etc., and the method equipment is cheap, so if an effective non-destructive evaluation method for cladding layer stress can be established, it will be of great help to improve the quality of remanufactured products and promote The smooth development of remanufacturing engineering is of great significance

Images