In the second report, thermal stress during dipping the simple plate in the molten zinc was analyzed. And it was indicated that maximum tensile thermal stress, (σt) max occurred at the lower side of plate, and caused LME-cracking at this position.
In this report, because of confirming the above crack position, the simulation test specimens for LME-cracking were devised, and were dipped in the molten zinc.
The results are as follows.
(1) LME-cracking occurred at the lower side of plate, and the results consisted with the results by analysis of thermal stress.
(2) The addition of the thermal stress and residual stress affected the initiation of the cracking.
(3) To make dipping velocity high, to give dipping direction careful consideration, or to make shot peening is a good example of preventing the crack.
