鋼ガス圧接部ふくらみの熱間せん断による非破壊検査（第３報） 有限要素法による鋼ガス及び熱間せん断時の変形と応力の解析

Abstract

In the previous report, an approximate model which describes the mechanism of bulge removal by hot shearing was presented. But the details of stress distribution and plastic deformation mechanism in this process which have influence on the occurrence of a linear defect could not be known experimentally because of its high temperature. In this report, the problem of determining temperature and stress histories, stress distributions during gas pressure welding of steel and subsequent hot shearing is solved on the basis of coupled thermal and mechanical energy balances using the finite element method. A nonlinear heat transfer analysis and a thermo-elastic-plastic stress analysis are performed simultaneously taking into account the temperature dependence of the material properties, heat losses due to convection and radiation, and phase transformation.Tensile stress is confirmed to be generated just under the edge in hot shearing which opens the joint when the welding condition is not suitable. The computational results are compared with experimental ones, showing good correlation between them.