COMPARISON STUDIES FOR AUTOMOTIVE EXHAUST VALVE AND INTAKE VALVE

Automotive cylinder valves include intake valve and exhaust valve. The intake valve opens and allows the air-fuel gas mixture to flow into the combustion chamber, and the exhaust valve opens to discharge combustion gas [1]. Temperature and corrosion resistance are the main choice-determining factors for both valves and these determine that chromium is an important constituent in the alloy used [2]. According to Smithells 2004, valve steel, i.e. stainless steel that had been modified in its chemical composition, is the most popular material used for commercial valve making. According to Larry Carley [4], for exhaust valve, it is made of austenitic stainless steel alloys, 21-4N (21% chromium). Exhaust valve is constantly blasted by hot exhaust gases and usually operates at 650