大断面铸态铁素体球铁的组织控制

试验研究了影响大断面铸态铁素体球铁组织的若干因素。结果表明，即使使用纯度不高的生铁，若控制Si的含量及应用微量元素Sb能完全消除大断面球铁中的碎块状石墨；在超厚壁500mm长方体中心获得完全球化的石墨；抗拉强度大于200MPa，延伸率大于9％，性能已达到原西德Castor标准。

Factors that affect structure of as-cast heavy section ductile iron are studied through experiment.The results show that the chunky graphite of heavy section ductile iron can be completely removed by controlling the content of Si and applying trace element Sb even in the condition of using poor raw material. Si leads to the formation of chunky gnaphite. But if Sb is added to the iron,high amount of ferrite can be obtained and no chunky grapite occured even in the high content of Si. Spheroidal ratio reaches over 90% inthe center of 500 millimeter thick cuboid. Tensile strength is greater than 200MPa,elongation greater than 8%. The structure and properties is the same as or better than those of west Germany Castor Standard.