2021 Volume 93 Issue 7 Pages 400-403
Al-Mg based alloy is a strong candidate material for automobile body parts because it does not require heat treatment and shows excellent ductility. In our previous studies, we found that Al-4.5Mg-1.0Mn based alloy added with 0.2% Si, 0.020±0.005% Sr, 0.008% Ti, and 0.016% B has both around 15% fracture elongation and low hot tearing susceptibility. However, the influence of hydrogen gas content in molten alloy on the susceptibility of Al-4.5Mg-1.0Mn based alloy has not been quantitatively investigated. In this study, the amount of hydrogen gas in the molten metal was varied under two conditions : a large amount (1.0cc / 100gAl) and a small amount (0.3cc / 100gAl). Through this, the influence of both hydrogen gas content and Sr, Ti, and B additions on the hot tearing susceptibility of Al-4.5Mg-1.0Mn based alloy was investigated. When there is a large amount of hydrogen gas, the addition of Sr, Ti, and B reduced hot tearing susceptibility. On the other hand, when there is a small amount of hydrogen gas, the addition of Sr, Ti, and B did not reduce the susceptibility. These results suggest that a certain amount of hydrogen gas is required to reduce hot tearing susceptibility by the addition of Sr, Ti, and B to Al-4.5Mg-1.0Mn-0.25Si alloy.
