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汽車发动机的排气閥由于在十分繁重的条件下工作,头部边緣部分极易損坏,使排气閥和气閥座不能密合,发生漏气现象,降低功率。排气閥通常用硅铬高合金鋼(硅2～3％,鉻8～10％,碳0.35～0.3)或硅铬钼高合金鋼(硅1.9～2.6％,鉻9～10.5％,钼0.7～0.9％,碳0.35～0.45％)制造。这两种鋼屬于馬丁体类热稳性鋼,在700～800℃高溫下具有較高的耐热性、耐蝕性和高温强度。
As the exhaust valve of a car engine works under very heavy conditions, the edge of the head can be easily damaged so that the exhaust valve and the valve seat can not be in close contact with each other, air leakage occurs and the power is reduced. Exhaust valves are usually made of high-alloy silicon steel (silicon 2 to 3%, chromium 8 to 10%, carbon 0.35 to 0.3) or silicon-chromium-molybdenum high alloy steel (silicon 1.9 to 2.6%, chromium 9 to 10.5%, molybdenum 0.7 ~ 0.9%, carbon 0.35 ~ 0.45%). Both types of steel belong to the class of martensitic heat-stabilized steels, which have high heat resistance, corrosion resistance and high temperature strength at 700-800 ° C.