Patent ID: 7307235

Claim:
A butt welding apparatus for butt welding end faces of two plate members by electric resistance heating, comprising means for supporting the two plate members such that the end faces abut each other and form a butt portion; a pair of electrode members disposed opposite to one another for performing electric resistance heat welding of the butt portion, said pair of electrode members comprising a first electrode member provided at a first side of the butt portion and a second electrode member provided at a second side of the butt portion opposite to the first side, said first electrode member being positioned so that it extends across the butt portion and having an outer surface with a press portion and a non-press portion, the first electrode press portion having a stepped surface towards the butt portion, and the second electrode member being positioned so that it extends across the butt portion; and means for causing relative movement of the first and second electrode members toward each other and contacting of a surface of one of the plate members with the first electrode member and causing the end face thereof to deform toward the end face of the other plate member, melt, and join therewith.