ENGINE VALVE FOR AUTOMOBILE MADE OF TITANIUM ALLOY EXCELLENT IN HEAT RESISTANCE

摘要

The present invention provides an engine valve for an automobile made of titanium alloy which is excellent in heat resistance, which engine valve for an automobile made of titanium alloy comprises, by mass %, Al: 5.5% to less than 6.5%, Sn: 1.5% to less than 5.0%, Zr: 4.6% to less than 6.0%, Mo: 0.3% to less than 0.5%, Si: 0.35% to less than 0.60%, O: 0.05% to less than 0.14%, Fe+Ni+Cr: 0.01% to less than 0.07%, and a balance of titanium and unavoidable impurities. By being provided with such ingredients, the valve is excellent in room temperature ductility and impact resistance after high temperature exposure in addition to creep resistance and high temperature fatigue strength exceeding a conventional engine valve and can withstand use at a higher temperature and longer time than in the past.