Metallurgical Technology Of High-Purity Industrial Iron With VIM Process

Industrial iron is a kind of alloy in which the iron content would be 99.6?99.8%,and the carbon content is 0.04%or less,and other components are as less as possible.Industrial iron has outstanding performance in both electromagnetic and mechanical aspects.And hence it is widely used in national defense,science researches,industrial manufactures and even people's daily lives.For instance,industrial iron is usually taken as the materials applied in the electromagnetism,packing and electromagnetic shielding.With the development of aerospace,nuclear and other industrials,the requirements for purity and quality of metal materials are getting higher.In order to obtain a variety of high temperature alloy,heat-resisting alloy,high-strength aging steel and etc,it is necessary to use high-purity industrial iron as raw materials.Therefore,it has a great significance to explore a low-cost,short process of highly pure industrial iron metallurgical technology.The main purpose of this study is exploring a process of smelting highly pure industrial iron by using highly oxygen content industrial iron in the vacuum induction furnace.The experiment is divided into two parts:in the first section the deoxidization and denitrification of high oxygen content industrial iron were carried out in the vacuum induction furnace.And then the smelting process was improved based on the situation of smelting and the chemical composition of pure iron.In the second section,statistic and analysis of inclusion numbers and compositions was performed.The results of this experiment are concluded as follows:The process of deoxidization with aluminum for industrial iron is not well for deoxidization and denitrification,and it's easy to produce Al2O3 inclusions.The process of vacuum carbon deoxidization with carbon has a good result,which can decrease oxygen content to 16×10-4%and nitrogen content to 15×10-4%.But it's easy to cause the splash of molten steel during the smelting process,and the smelting time is relatively longer and not easy to control.The deoxidization process after improved is that deoxidizing with aluminum firstly and then deep deoxidizing with carbon.Results showed that the best smelting process is planed to decrease oxygen content to 0.07%firstly and then decrease oxygen content to below 50×10-4%.Oxygen contents in the smelted pure iron can be decreased to 22×10-4%,and Oxygen contents can be decreased to 16×10-4%,also the smelting process is relatively stable and easy to control.The statistics of inclusions show that the amount of oxygen inclusions residual in the molten steel and the size of conclusions decrease with decrease of total oxygen content,and the ratio of inclusion size that under 2 ?m are increased.The analysis of inclusions component in high-purity industrial iron after deoxidization with aluminum and carbon showed that the main inclusions are FeO and a small amount of inclusions are Al2O3 and MgO·Al2O3.