溶接熱ひずみ履歴を受けた鋼の機械的特性と溶接継手の変形解析への適用

抄録

Studies of mechanical properties of steels subjected to thermal prestraining cycles have been presented as valuable experimental works for discussion of weld joint strength. It is noted here that if mechanical properties of steels subjected to thermal prestraining cycles can be denoted as a function of the Vickers hardness, then it is easy to determine material constant and analyze the deformation behavior of weld joint from the view of heterogeneity.
Three kinds of steels, a carbon steel (SM41B), an austenitic stainless steel (SUS304) and a martensitic stainless cast steel (SCS5) were used for experiments. The mechanical properties depend upon thermal prestraining conditions, especially peak temperature. For example, as the peak temperature is higher yield stress increases and also Vickers hardness increases. The experimental results indicate that elastic limit, yield stress, strength coefficient and strain hardening exponent of steels subjected to thermal prestraining cycles can be expressed as a function of Vickers hardness.
As an application, material constants for elastic-plastic FEM analysis can be determine from the Vickers hardness distribution of weld joint and in this paper weld joint with poor penetration is analyzed in terms of path independent J-integral, crack opening displacement (COD) and plastic zone extension.