Method for measuring internal residual stress of thick plate welding part

Abstract

The invention provides a method for measuring internal residual stress of a thick plate welding part. The method is based on an inherent strain method, the welding inherent strain is decomposed, and an original welding sample is cut into simple samples in different forms; measuring residual stress values of the simple samples by adopting an X-ray diffraction method, and then inversely calculating inherent strain distribution conditions of the simple samples by adopting a finite element method; finite element solution is carried out on the internal residual stress by applying the inherent strain. Comprising the following steps: decomposing inherent strain distribution according to distribution characteristics of inherent strain, cutting a welding part, and separating out a plurality of different samples; the cut surface is treated, and the residual stress of the cut surface is measured through an X-ray diffraction method; establishing a sample two-dimensional inherent strain calculation model according to a measurement result, and inversely calculating the inherent strain; finally, an original thick plate welding part internal residual stress calculation model is established, the inherent strain acts on the model, thick plate welding part internal residual stress distribution is obtained, the measurement result is reliable, and efficiency is high.

Description

technical field [0001] The invention belongs to the field of welding residual stress measurement, and particularly relates to a method for measuring the internal residual stress of a thick plate welding piece. Background technique [0002] Welding is an uneven heating and cooling process, and the welded parts inevitably generate residual stress. The effect of residual stress on structural stiffness, strength, and dimensional stability makes it an important factor to be considered in the design and manufacture of welded structures. At present, large-thickness plates are widely used to manufacture large-scale welded structures in petroleum, chemical, nuclear power, shipbuilding and other industrial fields. The complex and harsh service environment will accelerate the failure and damage of the structure. For thick plate welded parts, it is far from enough to obtain the residual stress on the surface. Therefore, it is very necessary to measure the internal residual stress of t...

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Problems solved by technology

According to the relevant welding process parameters and material properties, the device calculates the intrinsic strain by the formula, which only includes the longitudinal intrinsic strain and the transverse intrinsic strain. Altho...

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