溶接アークの熱源特性を考慮した溶接変形の数値解析

Abstract

It has become much more necessary to control weld distortion, which has negative influences on structural integrity, without loss of manufacturing efficiency. Commonly, angular distortion, which is controlled by temperature distribution along direction of plate thickness, is controlled by heat input parameter (Qnet / h2). However, it is also known the conventional heat input parameter is not always applicable in any welding process conditions. In order to clarify the effect of welding conditions on weld distortion more obviously, a better understanding and considering of the characteristics of temperature distribution during welding is required.In this study, the more accurate numerical analysis of weld distortion using arc physics based heat source modeling has been developed, as one approach for a better considering of the characteristics of temperature distribution during welding. Computational simulation of tungsten inert gas arc plasma based on mathematical modeling of the heat transfer from arc plasma to a welded plate is performed to obtain a more precise temperature distribution during welding. The temperature distribution obtained is used for a large-deformation thermal elastic-plastic analysis of weld distortion. In addition, the effects of welding process conditions on angular distortion are examined considering weld penetrations with the arc plasma process, and verified experimentally. Finally, a better understanding of the relationship between heat input parameter and angular distortion is discussed.