内燃机在工作时,其进、排汽门则经常处于高温约400～800℃和500～1000psi的爆发压力中,汽缸每分钟有2000～4000次的爆发,排汽门的承受温度比进汽门高、此外,汽门还要承受燃烧的气体腐蚀与冲击,以及本身与气门座的摩擦磨损,所以在设计和选择材料时,必须对此予以充分考虑,以保证其服役能力。 Internal combustion engine at work, its intake and exhaust valves are often in the high temperature of about 400 ~ 800 ℃ and 500 ~ 1000psi the outbreak of pressure, the cylinder every 2000 to 4000 times the outbreak, exhaust valve withstand temperature than the intake valve In addition, the valve is also subject to combustion gas corrosion and impact, as well as the friction and wear with the valve seat, so in the design and selection of materials, we must give full consideration to this to ensure its service capacity.