The valve seat is made of high chrome molybdenum alloy that introduced by internal-combustion engine academe of UK which is the technology by the 90's, According to the situation of country, Shanghai internal-combustion engine developed a new technology again which is melted by high temperature. So this material are be of high attrition endurance, high temperature endurance and high erosion endurance. Under normal condition, this product can make the engine drive 150~300 thousand kilometers. Our valve seats are suitable for engines imported from Europe, America, Japan, Korean and so on, they are of the best quality and have the competitive price in home and abroad.