Patent ID: 6906277

Claim:
A reinforcement butt stud welding method comprising the steps of: removably mounting an earth clamp having a conductor surface perpendicular to an existing reinforcement over the periphery of the end portion of said existing reinforcement; mounting a ring-like stud base composed of a heat-resistant electrically insulating material on the conductor surface of said earth clamp in a state in which the stud base is pressed against the conductor surface; bringing a distal end of a stud reinforcement loaded in a stud welding gun in contact with the end surface of said existing reinforcement; and conducting stud welding in a state in which a ferrule disposed over the periphery of the distal end portion of said stud reinforcement is joined to said stud base; wherein said stud base has a mounting opening in the central part, into which the end portion of said existing reinforcement can be inserted, a contact surface pressed against the conductor surface of said earth clamp is formed on a side surface in the axial direction of said mounting opening, and a joining surface for joining the distal end surface of said ferrule having gas release grooves and a collar receiving said ferrule and molten metal in the lower part are formed on the other side surface in the axial direction of the mounting opening.