超高铬铸铁气门座离心铸造工艺研究
Study on Centrifugal Casting Technology for Ultra-high-chromium Cast Iron Valve Seat
宋现锋， 邵 明， 屈盛官
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作者单位：（华南理工大学 机械与汽车工程学院， 广东 广州 510640）
中文关键字：离心铸造； 气门座； 小口径铸管； 超高铬铸铁
英文关键字：centrifugal casting; valve seat; small-caliber cast tube; ultra-high-chromium cast iron
中文摘要：根据离心铸造特点和超高铬铸铁的性能特点，利用自行设计的离心铸造机，实验得到材料为铬含量超过32wt%的超高铬铸铁材料气门座的离心铸造工艺：涂挂涂料温度、浇注前铸型预热温度、铁水出水温度和浇注温度分别为120～150 ℃、270～320 ℃、1500～1520 ℃和1460～1480 ℃，炉前用0.3wt%的75硅铁进行孕育处理；铸型转速1750 r/min，浇注速率1 kg/s，浇注完成后30 s打开冷却水，冷却150～180 s后停机、出型。检测结果表明：铸件硬度和金相组织等性能符合气门座的工况要求。
英文摘要：According to the characteristics of centrifugal casting and performance of ultra-high-chromium cast iron, a centrifugal casting process of valve seats using the self-designed centrifugal casting machine was got, and the material of the valve seats was ultra-high-chromium cast iron with more than 32% chromium content. The process is as follow, the temperature range of brushing paint, mold preheating, alloy liquid and pouring is 120～150 ℃, 270～320 ℃, 1500～1520 ℃ and 1460～1480℃, respectively, adding 0.3% 75# Fe-Si into the casting ladle as modifying agent before pouring alloy liquid into the mold; the mold speed is 1750 r/min, the pouring speed is 1 kg/s; the cooling water is opened after the pouring completion 30 s, and the machine is off after 150 s to 180 s, then removing the casting. The results show that the hardness and microstructure of the casting meets the valve seats' working condition.