Research Of Manufacturing Technology And Wear Characteristics Of High-power Engine Valve Seats

Valve-valve seat friction pair is one of the most important frictional pairs in the engine, because of the severe working condition, the valve seat is easy be worn out. The wear-out failure becomes worse as the increasing high power engine's compression ratio. This paper designed and developed centrifugal casting experimental device of valve seat, and formulated the corresponding metal mold centrifugal casting process route based on the selection of high chromium cast iron valve seat material composition and formula, developed a high-density tissue and high-performance valve seat blank to meet the using requirements of 396 series diesel engine, achieved the purposes of high performance valve seat's localization.This paper designed and developed a metal mold centrifugal casting valve seat experimental device. The device used a combination mold installation type of cantilevered and the roller-type. Centrifugal cast valve seat is a small caliber blank pipe, We design the gas vent and the bell-shaped front ring in the mold design process with the consideration of exhaust and small-caliber cast and so on. The results show that the machine has a smooth rotation, variable speed rang, and the casting has a good quality and yield.High-chromium cast iron valve seat centrifugal casting process was studied in this paper. The coating formulation: Zircon flour, Ca-bentonite and water were 2kg, 0.5kg and 2000ml. The speed of the mold is1600r/min, the temperature of the mold is 270℃-300℃, pouring temperature of the liquid metal is 1460℃-1480℃, casting rate: 1kg/s, we open the cooling water 30 seconds after casting completed for 150-180 seconds.This paper identified the high chromium cast iron valve seat material composition range and developed the charging formula based on the analysis of the foreign vavle seat. We also observed the microstructure and mechanical properties of the centrifugal casting valve seat, which meet the working requirements of the 396 diesel engine.We also studied the wear characteristic of the valve seat used the SRV-Ⅳwear testing machine, discussed the effects of temperature and load to the wear characteristic.The results show that, the wear resistance of the valve seat meets the requirements of high power engines.