1. Material of engine valve: 5Cr8Si2, 21-4N+5Cr8Si2,40Cr and 4Cr9Si2. 2.Processing method: Precision Forging Spray Welding nitriding grinding. 3.Surface treatment: Electroplate Chromate neutral salt spray test (NSS) adhesion and thickness of coating. 4.Checkout: Tensile and Yield Strength gauge capability study geometric tolerance Form and Position Tolerance Surface Roughness hardness.