PURPOSE: To reinforce a pipe without being restricted by the space of installation etc. by cutting the outer periphery of a pipe to a thickness that can be penetrated by welding, arranging reinforcements at the inside of the pipe at positions corresponding to the cut part and attaching the reinforcements from the outside by welding.
CONSTITUTION: Concave parts 4 are formed by cutting on the outer periphery of the pipe at positions where reinforcements 5 are to be fitted. The thinkness at the bottom of the concave parts 4 is made to a thickness (optimum value is about 0.5W2mm) that allows the parts to penetrate the reinforcements 5 arranged at the inside by welding. The reinforcements 5 are arranged at the inside of the pipe at positions opposite to the concave parts 4 by a support 6 provided with an electromagnetic magnet 6a at the tip. Then, concave parts 4 of the pipe are heated from the outer periphery by a welding torch 8 to melt the bottom of the concave parts 4 to fix the reinforcements 5. At the same time, built-up parts 9 are formed at the concave parts using a welding rod 7, and excessive built-up parts are removed from positions shown by alternate long and two short dashes lines.
OOMURA KEIJI
MURAKAMI YUKIMASA
TAMIYA TOBIO
