溶接低温割れにおよぼす非金属介在物の影響(第2報)

水素割れ発生,伝播に対する検討

抄録

In the previous work, it was obtained that reducing inclusion contents increased the risk of weld cold cracking.
In this work, further examination of the effect of nonmetallic inclusions on HAZ hydrogen induced cracking was carried out. The sensitivity of hydrogen induced cracking was evaluated by hydrogen charged three point bending test for synthetic HAZ.
The results in this work were as follows:
(1) At room temperature, inclusions acted as crack initiation site, so K_IC of hydrogen-free synthetic HAZ specimens decreased with increasing inclusion contents.
(2) In hydrogen-charged specimens, increasing inclusions result in the elevation of K_TH and decrease of crack growth rate. It was aquired that inclusions reduced the sensitivity of HAZ hydrogen embrittlement.
(3) It was considered that this effect of inclusions on reducing sensitivity of hydrogen embrittlement was mainly caused by the hydrogen trapping effect of inclusions.
(4) Ce treatment had no significant effect on crack initiation and propagation of hydrogen induced cracking.