| 摘要 |
<p>A flexure member having excellent dimension accuracy by stably forming a high temperature portion uniformly in a circumferential direction of a steel pipe and in a narrow range in an axial direction of the steel pipe by using a manufacturing device disclosed in Document 1. The steel pipe (1) is supported at a first position A while being transferred, the steel pipe (1) is subjected to induction heating at a second position B by an induction heating coil (14), and the steel pipe (1) is cooled at a third position C, thereby forming the high temperature portion (1a) that shifts in the axial direction of the steel pipe (1), changing a position of a grasping mechanism (15) of the steel pipe (1) into a three-dimensional direction in a region D, and giving a bending moment to the high temperature portion (1a), with the result that the flexure member is manufactured. In the case where the thickness of the steel pipe (1) is equal to or less than 2.0 mm, a transfer velocity V of the steel pipe (1) is set to 5 to 150 mm/sec, and an alternating current of 5 to 100 kHz is supplied to the induction heating coil (14) having a number of winding of 1. In the case where the thickness of the steel pipe (1) is more than 2.0 mm and equal to or less than 3.0 mm, the induction heating coil (14) having the number of winding of 2 is used, and a current frequency f (kHz) of the alternating current supplied to the induction heating coil (14) and the transfer velocity V (mm/sec) of the steel pipe (1) are adjusted so that relationships of f < 3000/V and f≥0.08V are satisfied. 5 kHz≤f≤100 kHz and 5 mm/sec≤V≤150 mm/sec are satisfied.</p> |
