An automatic detection device for welding residual stress

Abstract

The invention discloses an automatic detection device for welding residual stress, comprising: a base plate, a slider pushing mechanism, a slide table, a splint, an electric push rod machine and a hand drill; The slideway is slidably provided with a slider pushing mechanism. In the present invention, the strain gauges are fixedly installed on the strain gauge placement table in advance, and the position from the center of the circle and the angle between them can be set, which eliminates the cumbersome steps of manual calibration, reduces the amount of labor, and the position of the strain gauges is relatively fixed. To avoid the measurement result error caused by the inaccurate position of the strain gauge, push the weldment to be tested to make it contact with the strain gauge placement table, attach the strain gauge to the weldment to be tested and make a mark in the middle, and move the weldment to be tested backward For the weldment, turn it over 180 degrees with the turning device, use a hand drill to punch a hole at its calibrated position, measure the strain value before and after punching, and perform theoretical calculations to measure the residual stress of the weldment.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to an automatic detection device for welding residual stress. Background technique [0002] The existence of welding residual stress and deformation is an important factor affecting the brittle fracture strength, fatigue strength and structural stability of structures or components. The existence of welding residual stress will eventually threaten the reliability of welded structures or welded joints. There are many methods to actually measure the residual stress, which can be summarized into two categories, that is, the mechanical release measurement method with certain damage and the physical measurement method without damage. Due to the residual stress field inside the weldment, after drilling a blind hole with a certain diameter and depth anywhere in the stress field, the metal and the residual stress therein will be released, making the original residual stress field out of b...

AI Technical Summary

Problems solved by technology

If the difference in strain near the small hole before and after drilling is measured, the internal stress at the small hole can be calculated according to the theory of elasticity. For strain gauges, if the wire strain gauge is used, its angle and distance from the small hole are relatively fixed, and it cannot be flexibly applied according to the actual situation. Compared with the resistance strain gauge, the cost is higher, the measurement process is more workload, and the measurement steps are cumbersome. When there is a difference in the position of the strain gauge, it is easy to produce a large result error

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