（1. School of Materials Science and Engineering， Hubei University of Automotive Technology， Shiyan 442002， China 2. Department of Research and Development， Dongfeng Powder Metallurgy Corporation， Danjiangkou 442708， China）
Abstract：The powder metallurgy valve seat of clean fuel engine was prepared by the combination of alloy powder and vacuum infiltration sintering. The effects of different copper content and infiltration sintering temperature on the microstructure， density， hardness and crushing strength of the valve seat were studied. The results show that the high alloy valve seat material has poor compressibility and uneven density distribution under unidirectional pressing. With the increase of copper content， the hardness difference between the upper and lower parts of the valve seat is reduced， the density and crushing strength are obviously improved， and the valve seat has better performance when the copper content is 20% （mass percent）. With the increase of the infiltration sintering temperature， the density of the valve seat is almost unchanged， while the hardness and crushing strength increase firstly and then decrease， the best infiltration sintering temperature is 1 165 ℃. The valve seat material with 20% copper infiltration and 1 165 ℃ infiltration sintering for 40 min has the best performance， which has density of 8.14 g/cm3， upper hardness of 31.25 HRC， lower hardness of 30.48 HRC and crushing strength of 1 244.17 MPa.
2018, Vol. 28 
