| 摘要 |
PURPOSE:To obtain a high-strength suction valve consisting of a novel high- strength material which richly contains a heat resisting component, more particularly V by forging a heat resisting steel product contg. respectively prescribed ratios of C, Si, Cr, Mo, and V, then subjecting the steel to a prescribed heat treatment. CONSTITUTION:The heat resisting steel product contg. 0.32-0.42% C, >=0.8% Si, >=4.5% Cr, >=1% Mn, and >=0.8% V is forged. The heat resisting steel product after forging is then subjected to the heat treatment and surface treatment to obtain the suction valve which richly contains the heat resisting component and has the much higher dynamic strength than the conventional products. The above-mentioned heat treatment and surface treatment are executed under, for example, the following conditions: The steel is subjected hardening for 20 minutes at 1,050 deg.C, oil quench tempering for 1hr at 650 deg.C, air cooling and annealing for 1hr at 650 deg.C, and air cooling and soft nitriding treatment for 20min at 570 deg.C, then to quick cooling.
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