Prevention of the Transverse Cracks in Heavy Section Butt Weldments of 2 1/4 Cr-1 Mo Steel through Low Temperature Postweld Heat Treatment (Report 1) : Relations between Occurrence, or Prevention of the Cracks and Parameters of Residual Stress and Diffusi

概要

論文の詳細を見る
This research was conducted in order to clarify the cause of transverse cracks, which were observed in heavy section weldments by submerged arc welding process, and to investigate the possibility of preventing them by low temperature postweld heat treatment. The results obtained are outlined as follows : (1) Transverse cracks initiate in the weld metal just below the final layer of welds and gradually propagate both to the top surface and to the bottom surface. (2) The location of the largest residual stress in the weld direction corresponds to that of crack initiation and so does the location of the highest concentration of diffusible hydrogen just after welding. (3) The largest residual stress is nearly constant in the range of plate thicknesses over 50 mm. Meanwhile, the highest concentration of diffusible hydrogen just after welding increases with an increase in plate thickness. It decreases with an increase in interpass temperature during welding or in temperature of postweld heat treatment and thereby the cracks can be arrested. Judging from the result, prevention of the cracks can be made possible only by decreasing the concentration of diffusible hydrogen through postweld heat treatment under lower temperature than with a usual intermediate stress relief annealing.
社団法人溶接学会の論文
1979-04-01