| 摘要 |
PURPOSE: A method for improving fatigue limit of exhaust valve for automobile engine is provided to improve fatigue limit and corrosion resistance at high temperature by performing controlled water cooling instead of existing air cooling after forging operation in the exhaust valve manufacturing process. CONSTITUTION: In a manufacturing process of exhaust valve for automobile engine, the method for improving fatigue limit of exhaust valve for automobile engine comprises the processes of performing forging operation on a material for the exhaust valve; controlled water cooling the material for the forged exhaust valve to an ordinary temperature at a cooling rate of 150 to 200 deg.C/min; solution treatment of the controlled water cooled material for the exhaust valve to a temperature of 1,100 to 1,200 deg.C; tempering the solution treated material for the exhaust valve at a temperature of 620 to 760 deg.C for 60 to 90 min; and air cooling the tempered material for the exhaust valve.
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