| 摘要 |
PURPOSE:To prevent a liner ring from lag breakage due to overall quenching by giving the hardening process of high frequency quenching only to the inner surface of liner ring to make compressive stress act only on the inner surface. CONSTITUTION:A rotary pump is provided on the stationary side casing 2 with a liner ring 3 made of high hardness material to reduce liquid leaking from a gap between an impeller 1 and the casing 2 opposed to each other. Then, high frequency quenching process is given only to the inner surface 32 of liner ring 3 so that tensile stress T1 acts only on the extended inner surface 32. And the liner ring 3 is rapidly cooled to contract only the inner surface 32 so that compressive stress C1 remains only on the inner surface 32 with the outer surface 31 and the side surface 33 being restrained. Thus, the liner ring 3 is prevented from the occurrence of lag breakage by the conventional overall quenching process so that the liner ring 3 is prevented from dropping out due to cracks.
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