影响薄壁球墨铸铁白口倾向和球墨数量的因素分析

研究了不同的冷却速度、稀土加入量、碳量、硅量、Si／C、Mn／S及孕育处理等工艺时薄壁球墨铸铁球墨数量和白口深度的影响。结果表明，随着冷却速率增加，薄壁球墨铸铁石墨小球越多，但容易产生白口。冷速较大时，加入稀土元素进行孕育和控制碳当量，可以有效的消除薄壁球墨铸铁的白口现象，当Si／C大于0．80、Mn／S大于20时薄壁件白口倾向较小。

Factors Affecting Chilling Tendency and Spherical Graphite Amount of Thin Section Ductile Iron Castings

The effects of different cooling rate, rare earth addition, carbon content, silicon content, Si/C ratio, Mn/S ratio and inoculation on the amount of spherical graphite and chill depth of thin section ductile cast iron were studied. The results show that spherical graphite of thin section ductile iron increases with increase of the cooling rate, however, it is easier to result in large chilling tendency. Chilling tendency can be effectively eliminated by using rare-earth element inoculation and controlling carbon equivalent. When Si/C is above 0.80 and Mn/S is over 20, the chilling tendency decreases.