Quenching processing method and apparatus for splicing plate for high strength bolt friction joining

摘要

PROBLEM TO BE SOLVED: To inexpensively and rapidly manufacture a splice plate with high performance, which has high coefficient of friction by heat treatment with a laser having a controlled power density. SOLUTION: A quenching method for the splice plate for friction-bonding a high strength bolt, which has a continuous angular unevenness concentrical to a bolt hole, comprises adjusting a beam width and spatial distribution of power density of a linearly condensed laser beam and the scanning speed, to harden an angular salient so as to give higher hardness than that of a base metal, when linearly condensing the laser beam so as to give a longer line than a diameter of the angular uneven part, and scanning the angular uneven part for heat treatment. In particular, the laser beam has preferably a relatively lower power density in the central part of the longitudinal direction than in the end part of the longitudinal direction, of linearly or prolate elliptically condensed laser beam.