WELDING AND CONNECTING METHOD FOR EXHAUST PIPE

PURPOSE:To obtain a connection with prescribed strength and to reduce welding cost by performing butt welding by magnet arc welding between end connecting surfaces of an exhaust pipe to be connected and connecting exhaust pipe which are nearly equal in thickness. CONSTITUTION:The connecting end surface 2a of a coupling short pipe (connecting exhaust pipe) 2 is so chamfered that its external diameter size is equal to that of a head exhaust pipe (to be connected) 1. Then, electrode rings 5 and 6 connecting to an AC power source 4 are fitted around external circumferential surfaces of the pipes 1 and 2, and an annular electromagnetic coil 7 is provided over and between the pipes 1 and 2. While a voltage is applied between the rings 5 and 6, the coil 7 is excited. Then, an arc 8 turning in a circumferential direction is generated between the connecting end surfaces 1a and 2a of the pipes 1 and 2, and consequently the surfaces 1a and 2a are fused. For this purpose, the surfaces 1a and 2a are connected together to couple the pipes 1 and 2 with prescribed strength.