Non-oriented Electrical Steel Rh Desulfurization Technology Research

Currently, in Panzhihua Iron & Stell (Group) Co. the sulfur content in non-oriented electrical steel is controlled by deep desulfurization of iron and reducing the sulfur content of sulfur from converter, but the sulfur content just arrive at 0.008% or less,which is unable to meet the quality of non-oriented electrical steel. Therefore, there is an urgent need to research and develop high quality non-oriented electrical steel with ultra-low carbon, ultra low sulfur in Panzhihua Iron & Stell (Group) Co..In this paper, based on Panzhihua Iron & Stell (Group) Co.'s production equipments system and process, the auther have explored a desulfurization method of directly adding the desulfurization agent into the vacuum chamber of RH furnace. The use of CaO-CaF2 slag desulfurization equipment will cause severe erosion and the environment pollution, the auther haved experimented and selected a kind of low fluoride RH slags which is mixture of CaO,Al2O3,MgO, BaO, CaF2 and Na2O. By comprehensive consideration of physicochemical properties of slag in the study, the optimized composition of refining slag ought to be CaO/Al2O3 value:2～2.2, MgO:6%～9%, BaO:13%～15%, CaF2:5%～8%, Na2O: moderate. The use of new formulations sulfur content have decreased 37.5% in finished non-oriented electrical steel product,reduces the erosion of equipment and environmental pollution.We have determined the key process control conditions of RH desulfurization by the industrial study in Panzhihua Iron & Stell (Group) Co. for example the desulfurization processing time, ladle slag composition and ladle slag alkalinity.(1)The alkalinity of ladle slag is required not less than 5.(2)The (FeO+MnO) content in ladle slag should be controlled to below 12%.(3)RH desulfurization process should more than 10 minutes.(4)The MgO content in ladle slag should be controlled between 8% and 10%.On this basis, we identified a suitable non-oriented electrical steel RH desulfurization process at this stage Panzhihua Iron & Stell (Group) Co..Process route is:LF process should control the ladle slag alkalinity not less than 5 and the (FeO+MnO) content below 10%.It more than 10min of natural decatbutization after force decarbutization. The vacuum cycle time more than 10min after sorbent was added.when the end of desulfurization equipement should be maintenance.The sulfur content in non-oriented electrical steel is controlled to below 0.005% or more less by the new process, which increases non-oriented electrical steel quality and lays a foundation for the development of higher level of non-oriented electrical steel.