可锻铸铁的成份限制甚严,碳,矽,锰,硫,磷都有一定范围。可锻化退火铁需要很长时间约100—200小时。苏联对于含铬铸铁添加矽铁或矽铁+碳化钙於盛铁桶中,而后进行退火。这种炉外加料配制的可煅铸铁称为加制可锻铸铁,其退火时间缩短至40小时。苏联采用可锻铸铁的快速退火法,把退火时间缩短至20—30小时。但快速退火必须用具有一定成份(低碳低硫)的铸铁并用电炉或反射炉熔制,才收得良好的效果。若用一般制造方法和普通生铁在冲天炉制黑心可锻铸铁,则不仅退火时间需要100小时以上,且不能保证质量。现有许多工厂用冲天炉熔制可锻铸铁,由於技术上存在问题,废品率甚高竟有达50％以上者。因此可锻铸铁的炮制与退火方法亟须改进,俾得缩短退火时间,提高产量並质量。我们经过数月研究,认为若用冲天炉熔制,可於盛铁桶加镁处理制成白口铸件,而后直接装炉退火,仅需12—14小时便可得到黑心纯铁体可锻铸铁。我们在灵山农具厂经半年的试验研究,结果良好,废品率由28％降至0.75％,产品质量超过一般黑心可锻铸铁的标准。这种加制方法是与苏联的加制可锻铸铁的意义相同,只是不用矽铁或矽铁+碳化钙为加制剂而是用镁为加制剂。退火时间比之一般制造可锻铸铁方法缩短到原来的1/10,比之加矽 The composition of malleable iron is very limited, carbon, silicon, manganese, sulfur, phosphorus have a certain range. It takes a long time to malleable anneal iron for about 100-200 hours. The Soviet Union for ferrous chromium containing cast iron or ferrosilicon + calcium carbide in the iron bucket, and then annealed. Calcined cast iron formulated outside this furnace is called the addition of malleable cast iron and its annealing time is shortened to 40 hours. The Soviet Union adopted a rapid annealing method of malleable iron, reducing the annealing time to 20-30 hours. However, rapid annealing must have a certain composition (low carbon and low sulfur) cast iron and electric furnace or reflow furnace melting, only to receive good results. If the general manufacturing method and ordinary pig iron in the cupola black heart malleable iron, not only annealing time takes more than 100 hours, and can not guarantee the quality. Many existing factories use cupola to melt malleable iron, due to technical problems, the rejection rate is as high as more than 50%. Therefore, malleable iron processing and annealing methods need to be improved, so as to shorten the annealing time and improve the yield and quality. After several months of research, we think that if the use of cupola melting, can be made of white iron castings magnesium bucket made of castings, and then directly furnace annealing, only 12-14 hours can be black heart pure iron malleable cast iron. After a half year of experimental research at Lingshan Farm Tools Factory, the result was good with the rejection rate dropping from 28% to 0.75%. The quality of the products surpassed the standard black malleable cast iron. This method of adding is the same as the meaning of the Canadian made malleable iron, except that instead of using ferrosilicon or ferrosilicon + calcium carbide as additive, magnesium is added as a preparation. Annealing time than the general method of manufacturing malleable iron shortened to the original 1/10, compared with silicon