강관 고주파 저항용접에서 용접부 주위의 응력 분포 해석

Abstract

This study proposes a thermal elastoplastic model for the high-frequency resistance welding process of steelpipes, aiming to clarify the characteristics of the residual stress distribution around the weld zone byanalyzing the model. To achieve this, the effect of springback phenomena during the pipe-forming processwas analyzed, and numerical models for the electromagnetic and heat transfer phenomena occurring during thewelding process were developed. Finite element analysis of the proposed thermal elastoplastic model predictedthe distribution of residual stresses in the weld zone, showing that the longitudinal stress was distributedbeyond the yield stress of the material up to approximately 10 mm from the joint, whereas thecircumferential stress reached its maximum magnitude, approximately half of the yield stress, approximately10 mm away from the joint. The magnitude of the radial stress was low, and the stress distributions on theinner and outer surfaces of the steel pipe were similar. The springback occurring during forming and theelectromagnetic forces during welding had nearly no effect on the stress distribution. The proposed model andanalysis results can be used for strength analysis to predict the fractures of steel pipes.