1979 Volume 48 Issue 9 Pages 689-695
The feasibility of underwater welding by the submerged arc welding process is investigated. In this process, a special flux rrixed water glass with MF43 is used to stabilize arc and to protect the part being welded from the sorrounding water.
Welding experiments are done by using steel for welded structure SM41 of 9mm in thickness and it is ascertained that this process may be put to practical use.
Main results are summerized as follows:
(1) Welding arc can be generated easily and kept in stable, if only proper welding conditions are selected. Especially, good welds can be obtained easily by using a special flux mixed 40wt% water glass with MF43.
(2) The weld metal includes blowholes to some extent.
(3) The hardness of the underwater weld seems to be relatively low.
(4) Weld metal has the tensile strength of 82% of that of base metal.
(5) Cooling rate at 500°C at bond is about 23°C/sec under water and 10°C/sec in air, the former being about only 2 times higher than the latter. The former seems to be lower value than those by any other underwater welding processes.