改变球铁中的含碳量,会影响其凝固时的石墨析出量,即石墨球的平均尺寸或数量。尽管球铁含碳量一般在3.5～3.9％之间,但理解降低含碳量对球铁机械性能影响是很重要的。将球铁中的含碳量从4％左右降到2.5％。仅使抗拉强度和弹性极限略有增加(约23～31N/mm~2),延伸率约增加5％,最大冲击值有很大改善,如图所示。而对脆-韧性转变温度影响不大,随着含碳量从4％降到2.5％,其石 Changing the amount of carbon in the ductile iron will affect the amount of graphite precipitated during solidification, ie, the average size or number of graphite balls. Although the ductile iron generally has a carbon content between 3.5 and 3.9%, it is important to understand the effect of reducing the carbon content on the mechanical properties of the ductile iron. The ductile iron in the carbon content from about 4% down to 2.5%. Only a slight increase in tensile strength and elastic limit (about 23 ~ 31N / mm ~ 2), an increase of about 5% elongation, the maximum impact value has greatly improved, as shown. While the brittle - ductile transition temperature has little effect, with the carbon content from 4% to 2.5%, the stone