上钢三厂从74年全面采用石灰石砂后,共生产铸钢件近七万吨,平均合格率达98.54%,他们的经验是通过试验、研究找出缩沉、气孔、CO中毒、裂纹产生原因,采取刷涂料的措施,使上述问题得到不同程度的改善和解决,并对工艺和操作进行了整顿,加强了工艺、技术管理. After obtaining full utilization of limestone sand from 74 years, the No. 3 Steel Plant produced a total of nearly 70,000 tons of steel castings with an average passing rate of 98.54%. Their experience is to find out the phenomena of shrinkage, stomatal, CO poisoning and crack generation through experiments and studies The reason is that the measures taken by brushing paint have improved and solved the above problems in varying degrees and rectified the processes and operations and strengthened the process and technical management.