ルート割れと最高かたさ(昭和59年度秋季全国大会論文発表講演論文)

概要

論文の詳細を見る
Effects of maximum hardness in the HAZ on root crack initiation in the JIS-y (oblique-Y groove) cracking test are discussed. The values of critical hydrogen concentration Hc at the location of root crack initiation at 100℃ on the way of cooling, were calculated, assuming uniform diffusion of hydrogen through weld zone. The value of log Hc decreased linearly with an increase of H_<max>, depending on the intensity of restraint. The correlation between llog Hc and H_<max> was found to be far poorer than that between log Hc and Pcm, Ito and Bessyo carbon equivalent, which is adequate for low carbon content steels. An analysis by the cracking parameter P_<HA>, proposed by the author considering local accumulation of hydrogen at the site of crack initiation, revealed that log Hc vs. H_<max> relation is severely affected by the C% of test steels, thus a wide scatter in Hc values. For the same value of H_<max>, a lower carbon content is more favourable against root cracking. The estimation agrees well with the JIS-y test result. The critical values of H_<max> for crack-free welding without preheating, have been P_<HA>-estimated depending on H_D values. As an application, the P_<HA>-estimated critical values of H_<max> agree satisfactorily with the Harasawa-Hart's observed values in the H-type self-restrained root cracking tests.
社団法人溶接学会の論文
1984-08-05