抄録
It is difficult to find out such a suitable rod for either gas or electric welding of two “Alumers (hot-dipped aluminum coated steel)”, as not to cause any cut-off defect in the Al-Fe alloy layer around the welded border line.
Therefore, V-shape cut off is usually made first along the welding line of two Alumers, which, then, can be welded with ordinary welding rod, and this welded line is finished, if necessary, by covering with thin layer of special steel welding rod. In Fig. 1, the cut-off defect can clearly be seen in the Al-Fe alloy layer, which has been one of the gravest defects of Alumer, unsolved since it turned up in the Japanese industry.
A series of experiments, therefore, was carried out to find out a suitable rod especially for electric welding of “Alumer”, and the result was as follows:
(1) By using the suitable flux, it is possible to weld Alumers together with the Al or Al-alloy welding rod, and stable Al-Fe alloy layer can be obtained.
(2) With the fluxes of main ingredients of KCl, NaCl, and AlE3, and addition of small amount of K2SO4 and NH4Cl as ionization medium, the weldability is much improved.
(3) With the rods of Al-Si (Si 11%) alloy as core metal, more stable layer is obtained, and the weldability also becomes better.
(4) It is necessary to use D. C. welding of reversed polarity arc.
(5) Comparing high temperature oxidation resistivity, the welding with Al-Si rod is superior to that with the stainless steel rod.
