Effect of Pre- and Post- Heating on Weld Cracking of Low Alloy Steels : Some Basic Problems in the Application of Pre- and Post- Heating to Weldment for the Prevention of Cold Cracks

概要

論文の詳細を見る
Some basic problems in the application of supplementary heat to a weld joint before or after welding have been investigated using a mild steel, medium carbon steels, 50 to 100 kg/mm^2 high tensile steels and low alloy steels. The results indicate that (1) the cold cracking can not occur at the temperatures above the critical point, which is 80℃ in the case of HT80 steel joint, (2) the delayed cracking may occur at low temperatures, (3) the activation energy determined by incubation time of delayed cracking is 11, 000 cal/mol at the temperatures over -30℃ and 2, 300 cal/mol below -30℃, (4) the activation energy determined by the effect of postheating on the cracking is 13, 000 cal/mol independently of steel grade, and (5) the preheat temperature may be reduced by using postheating, but thermal stress cracking may occur under certain conditions under which blue brittleness or precipitation brittleness takes place.
社団法人溶接学会の論文