Prevention of the Transverse Cracks in Heavy Section Butt Weldments of 2 1/4Cr-1Mo Steel through Low Temperature Postweld Heat Treatment : (Report 3) Correlation between Reduction of Hydrogen Concentration through LTPWHT and Its Treating Conditions

概要

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In order to clarify the relationship between the reduction of hydrogen concentration through low temperature postweld heat treatment and its treating conditions, the analyses on the diffusion of hydrogen during the treatment were carried out using an analytical computer program in which the influence of the gradient of hydrostatic stress caused by welding residual stress distributions was taken into consideration. As a result, it was found that the ratio of the highest hydrogen concentration at any time during the treatment to the hydrogen concentration at a point right below the final pass of welds just after welding, could be arranged by a parameter (τ+D_pt_p), where τ and D_pt_p are the parameter of hydrogen diffusion determined by welding conditions and the product obtained by multiplying the diffusion coefficient at a temperature of the treatment by its holding time, respectively. The influences of the dimensions of the weld zone, such as plate thickness or groove width, upon its relationship were also clarified. Moreover, the diffusion coefficient of hydrogen, which becomes a very important factor when we determine the concrete conditions of the treatment for preventing the cracks, was obtained in the temperature range of 150℃ through 300℃.
社団法人溶接学会の論文
1979-10-01