抄録
Al–Mg–Si series alloys have some sensitivity of liquation cracking in welding heat affected zone (HAZ). In this report, influence of manganese in 6082 on susceptibility of this liquation cracking was studied using a welding thermal stress cycle simulator. As the results of the butt welded joints, this liquation cracking was suppressed by the addition of Mn. From the welding thermal stress cycle simulator, it has been cleared that with the addition of Mn, the lower limit of the brittle temperature range between nil-ductility temperatures on heating process and on cooling process, was raised to the same or higher temperature than solidification temperature of the weld metal. This was because that the effective Si content in matrix was reduced by generating the Al–Fe–Mn–Si compounds due to the addition of Mn. In this case, solidification shrinkage strain of weld metal did not work to open the solid state grain boundary in HAZ to cracking easily.
