抄録
The gas content of ordinary die casting is very high, and as a result, sufficient welding strength cannot be achieved due to blowhole (BH) formation when such casts are welded. Under this circumstance, it is necessary to find suitable welding conditions so that BH can be suppressed even when a casting contains a certain amount of gas. This paper discusses attempts to see if it is possible to suppress BH and thereby ensure the reliability of welding strength by controlling heat input. We have found out that when the gas content is below 3cm3/100gAl, base metal rapture occurs independent of the welding conditions. For gas contents in the range of 3 to 5cm3/100gAl and 5 to 7cm3/100gAl, the heat input should be less than 66J/mm2 and 52J/mm2, respectively. However, it is very difficult to achieve base metal rapture when the gas content in the casting exceeds 7cm3/100gAl. Moreover, in order to ensure the reliability of welding strength, the control value of the BH density has been found to be 16% when welded under controlled heat input.
