抄録
Temper bead welding is applied as one of repair methods for reactor vessels made of low alloy steel. It is desirable that hardness of the weld heat affected zone in the temper bead weld is less than 350HV to prevent the cold cracking. As diffusible hydrogen in a factor of cold cracking hardly diffuses in austenitic weld metal cold, cracking is available to be prevented. Cold cracking and the mechanical properties of the weld by gas tungsten arc welding using welding material of Ni-based alloy was evaluated. Even if maximum hardness in the weld heat affected zone is more than 400HV, cold cracking don't occur, and also the mechanical properties are good.
