... enginesSuitable for automobiles, trucks, tractors, all types of light to heavy-duty diesels engines, earth moving machineries, stationary, ... treatments as below:Tuff trided/nitrided: valves are nitrided to increase the exhaustion strength, corrosion- and wear-resistantChrome-plated ... hard faced): valves made by using deposit of stellite to get high hot hardness at seatBimetal: valve made by joining ...