Abstract
The brittle ranges of the multi-pass welded parts arc investigated, using both Killed and Rimmed steels, low-hydrogen type and ilumenite type arc-electrodes. Further, the variation of the impact values after heat-treatment are described. As the results of these experiments followings are known ;
1) Variation of the impact values after heat-treatment are somewhat different depending on the part where the impact specimens are adopted.
2) It was recognized that there exist inferior toughness in the bond.
3) The most brittle part seems to be more apart from the bond than in the case of single-bead weld.
Using the synthetic impact specimens, improvement of the toughness in the neighbour of bond are investigated. Further, reliability of this specimen are considered comparing with the test results described in the previous report. The better impact value seems to be gained after the heat-treatment in the neighbour of 700°C. Rolled directionality of the parent plate must be considered to calculated the synthetic impact value from the common testing results. Considering some correction caused by directionality, it seems to be reliable to use synthetic impact specimen.
