再谈提高原铁液质量的关键技术(1)

Talk Again about the Key Technique to Improve Quality of the Base Iron Melt(Ⅰ)

详细地论述了铸铁件的力学性能、铸造性能、加工性能及缺陷与原铁液质量的关系。原铁液的冶金质量要求包括:(1)过热温度要高,高温过热的原铁液对铸铁质量有重要影响,指出了对高温过热铁液的错误看法;(2)C、Si、Mn、P、S五大常规元素、合金元素及微量元素的含量要准确,波动范围要小,随着高质量要求铸件及高端铸件生产的增多,灰铸铁和球墨铸铁的化学成分定位也有变化;(3)铁液纯净度要优良,包括O、H气体含量低,N2含量适当,氧化渣及非金属夹杂物低,有害微量元素低;(4)影响孕育后石墨化的因素不仅是孕育剂、孕育方法、孕育温度,改善原铁液本身的形核潜能力也十分重要,废钢增C工艺、预处理工艺等都是提高原铁液形核潜能最有效的措施。

The relation between the mechanical properties,casting properties,machinability as well as the defects of the cast iron castings and quality of the base iron melt were described in detail. The metallurgical quality requirements of the base iron melt included：（1）Its superheating temperature was to be high,because the high temperature superheated base iron melt had important influence on the quality of the cast irons. Some incorrect view points were pointed out.（2）The contents of C,Si,Mn,P,S five main elements,contents of alloying elements and contents of trace elements were to be accurate,their fluctuation range must be small. Along with the increasing of the high quality required castings and the high-end castings production,the chemical composition determination also changed.（3）The purity of the iron melt should be good,including low contents of gas O,H,proper content of gas N,low contents of oxidizing slag and non-metal inclusions,low contents of destructive trace elements.（4）The factors influencing graphitization after inoculation were not only the inoculants,inoculating processes,inoculating temperature,improving the latent nucleation ability of the base iron melt itself was also very important.Recarburating process of the steel scrap,pretreating process were the most effective measures to increase the latent nucleation ability of the base iron melt.