WELDING MATERIAL FOR ELECTRON BEAM WELDING, WELDING METHOD, WELD ZONE OBTAINED BY THIS WELDING METHOD, AND THEIR USE

摘要

PROBLEM TO BE SOLVED: To prevent the formation of silicate causing cracks by regulating the ratio of content between Mg and Si, by mass, in an Al-Mg-Si alloy material to a stoichiometric ratio or above. SOLUTION: The 6000 series alloy is characterized by the formation of Mg2 Si compound, in crystalline grain boundaries, capable of providing the alloy with mechanical properties after heat treatment. In the case where the alloy contains the above compound and excess Si, silicate causing cracking is formed in a heated zone or melted zone. On the contrary, in the case where Mg is in excess, no trouble is caused in the state of a weld zone. Accordingly, in order to prevent the formation of silicate, all the Si component is formed into an alloy with Mg to form the above Mg2 Si. Actually, it is preferable to regulate the mass ratio of content between Mg and Si to =1.75.