| 摘要 |
PROBLEM TO BE SOLVED: To obtain a torch for welding, by which the change of a curvature can be prevented even when comparatively large external force is applied, and which can be manufactured at a low cost even in the case of a small lot. SOLUTION: A round rod 10 made of a beryllium copper alloy, to which an age hardening treatment is not applied yet and which is rolled or extruded, is prepared. By forming a hole 11a by piercing, which extends in a center in the axial direction of the round rod 10, a pipe 11 is manufactured. By bending the pipe 11 by using a jig such as a bender, etc., a curved pipe 13 is manufactured. The age hardening treatment is applied to the pipe 13, by which self- cooling is performed after heating the curved pipe 13 at 300-360 deg.C for one to four hours. By machining and threading the curved pipe 13 after the age hardening treatment, a conductive pipe is completed.
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