| 摘要 |
PURPOSE:To give uniform heat treatment effect to the whole parts of alloy by making gradually the irradiation intensity of the heat rays small in case of melting the surface of low-m.p. metal such as Al alloy with the irradiation of the high-density energy heat rays and quenching it to form a finely-divided structure. CONSTITUTION:The high-density energy heat rays such as a laser beam 2 are irradiated on the surface of a low-m.p. alloy plate 1 such as Al alloy and the surface of the Al alloy plate 1 is locally melted and thereafter quenched. The wear resistance is increased because the metallic structure of the part to be treated is made dense and hardened. In such a case, since the adjacent part 1a wherein the heat rays are irradiated, melted and quenched is made to the high temp., the temp. of the part is measured with a thermocouple 3 buried in the transferring direction of the heat rays 2 and the intensity of the heat rays 2 is slowly made weak in accordance with the temp. or the transferring velocity of the heat rays 2 is made speedy and the heat rays 2 are scanned and irradiated so that the temp. hardly wholly reaches the prescribed heat- treating temp. or above and the uniform wear resistant hardening layer is formed on the whole surface of Al alloy.
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