| With the rapid development of electric power industry in our country,the concept of green economy is constantly deepening,the proportion of high efficiency motors is gradually increasing,and the demand for non-oriented electrical steel is rapidly growing.In addition to high purity steel smelting process,high precision cold and hot rolling process and precise temperature control annealing process are also required in the production of electrical steel.Therefore,electrical steel is called "artwork in iron and steel".The production level of electrical steel is one of the important symbols to measure the technological level of iron and steel enterprises.Baotou Steel Sheet Mill,as an advanced plate production base with first-class technical equipment,advanced technology and management experience in the world,has started to establish a production system of cold-rolled non-oriented electrical steel on the basis of the existing production lines through capital construction and technological renovation in order to further improve the added value of plate products and the level of production technology,optimize product structure and enhance the competitiveness of enterprises.Presently,the production process of non-oriented electrical steel at home had been relatively mature and widely used.However,the medium and low grade non-oriented electrical steel based on CSP technology was less studied.The whole process of 50W800 medium and low-grade electrical steel with the production project in Baotou Steel Thin Plate Plant were researched in this pater.In this paper,two 50W800 test schemes from composition to cold and hard coil continuous stripping coating were designed.The influence of refining composition,hot rolling reduction rate,coiling temperature,cold rolling reduction rate,cold and hard coil annealing process on the structure and properties of slab,hot rolling and continuous stripping coating were discussed by tracing the microstructures and properties of slabs,hot rolling and continuous stripping.The results showed as follows:(1)The increase of silicon content would promote the growth of columnar crystal in billet;(2)High temperature coiling at 700-750? in hot rolling process could promote the coarsening of inclusions and precipitates,reduce obstacles to grain boundary movement,and be more conducive to grain growth;(3)High temperature annealing at 840-860? in annealing process could promote the growth of grain size and enhance the magnetic properties of products.(4)Increasing silicon and phosphorus content in non-oriented electrical steels could improve the magnetic properties of products.In addition,the problems of nodulation of rollers in continuous annealing furnace for coldrolled coils were also explored,which seriously affects the quality of products in the production process of electrical steel.Some solutions such as nodulation roll positioning,on-line grinding roll,stop-line grinding roll,continuous grinding roll and stop-rolling of nodulation rollers had been put forward.At the same time,the precise cutting of non-oriented electrical steel could be realized by means of ibaPDA analysis template.Also,the problem of excessive local performance and thickness of electrical steel coils was solvedBy carrying out the industrialization test scheme,the process of 50W800 grade composition design,continuous casting and rolling,pickling and cold rolling,annealing coating were worked out.Finally,the optimum process route and operation main points were optimized.The bulk supply of 50W800 non-oriented electrical steel would be realized.The product performance could meet the market and customers special requirements. |
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