The hot rolled plate of low temperature high magnetic induction grainoriented silicon steel was treated by electric heating. The experimental results showed that the hot rolled sheet with equivalent normalizing plate texture components can be obtained by heating hot rolled sheet from room temperature to  1 000 ℃  with a rate of 55 ℃/s and then cooled which involved maintain 25 s during the cooling process from  1 000 ℃  to 950 ℃. The possibility of adding electric heating devices in the back section of hot rolling mill was discussed according to the experimental results.

As the fourth intelligent plant of silicon steel put into production, Baosteel has formed six series,more than 50 brands of grain-oriented electrical steel products, such as P series of high magnetic induction grain-oriented electrical steel, R series of laser scribing grain-oriented electrical steel, G series of ordinary grain-oriented electrical steel,LM series of low noise grain-oriented electrical steel,W/Y/Z series of special coating grain-oriented electrical steel, and HS series of heat resistant grain-oriented electrical steel, which can meet the needs of different customers. In this paper, the application of Baosteel's thin gauge grain oriented electrical steel products, especially B23R075, B20R070 and B18R060 were introduced for power transformer.

The effect of acid soluble aluminum (Als) content on precipitation behavior of the precipitates from the normalized plate was investigated in high magnetic induction grainoriented silicon steel. The results showed that the precipitates mainly consist of AlN, MnS and compound precipitates of AlN. With the increase of Als content, the amount of precipitates increases, but the average size of precipitates does not change much. The coarse precipitates in the normalized plate are basically compound precipitates, most of which take MnS as the core and AlN is extrapolated on the surface of MnS, while the fine precipitates in the normalized plate are mostly single precipitates. In the normalizing cooling stage, there are many fine AlN particles near the pearlite region because of the precipitation of supersaturated AlN and N near the pearlite region of normalizing plate. 

High silicon steel has excellent soft magnetic properties and is an ideal material for  iron cores of medium and high frequency electric motors. 6.5 %Si steel sheet with a thickness of 0.30 mm was prepared by double roll continuous casting-hot rolling-warm rolling-annealing process. The effects of different warm rolling processes on the texture and final magnetic properties of 6.5 %Si sheet rolling and annealing were studied by X-ray diffractometer and magnetic measurement. The results showed that the lower the warm rolling temperature is, the more favorable the formation of {001}〈0vw〉 texture is in the core of the sheet. The samples rolled at 600 ℃ and 500 ℃ contain mainly γ texture after annealing, while the samples rolled at 400 ℃ contain both γ texture and η texture with higher strength after annealing, and the corresponding magnetic induction value is high. At the same annealing temperature, {001}〈0vw〉 texture does not form in the two step rolling process, and η texture does not form in the sample after annealing, and the magnetic induction of the sample is lower than that of the one step rolled sample. Therefore, low temperature rolling is conducive to forming favorable η texture and improving magnetic induction of samples during annealing.

Four kinds of non-oriented 4.5 % Si steels with different mass fraction of Y (0, 0.006 %, 0.012 %, 0.016 %) were analyzed for the effects of Y on microstructure and magnetic properties of annealed sheets. The results showed that Y effectively modified nano scale square TiN and Al2O3 inclusions into spherical TiO2, Al2O3 and Y2O2S composite inclusions, coarsened the size of inclusions and reduced the number of fine inclusions dispersed in 0-500 nm. Thus, adding appropriate amount of Y increased the grain growth rate and reduced the activation energy of grain boundary migration, and the interaction of magnetic domain with grain boundary and inclusions led to the decrease of loss and iron loss. However, excessive Y increased the fine inclusions, enhanced the effect of pinning grain boundary and reduced the grain size of the annealed sheets. The {111} oriented grains nucleated and grew preferentially around the fine inclusions during annealing, the addition of rare earth Y reduced the inclusion density, and the enrichment of rare earth Y at the grain boundary reduced the nucleation advantage of {111} grains at the grain boundary, so the addition of rare earth Y weakened the strength of γ texture. The results showed that the sample containing 0.012 % Y has the highest B50 (1.655 T) and the lowest iron loss at each frequency, P1.0/50=1.41 W/kg, P1.0/400=19.28 W/kg and P1.0/1000=77.69 W/kg respectively.

The corrosion behavior of 50W800 non-oriented electrical annealed steel under neutral salt spray condition was studied, and the causes of corrosion were analyzed.Metallographic microscope, scanning electron microscope (SEM) and energy spectrum analysis (EDS) were used to analyze the microstructure of the annealed samples, and the macroscopic and microscopic corrosion morphology of the 50W800 annealed samples of non-oriented electrical steel were analyzed to determine the corrosion reasons of the annealed plates.The microstructure analysis results showed that the metallographic structure of the 50W800 annealed sample of the nonoriented electrical steel is equiaxed crystal ferrite structure. The typical inclusions in the 50W800 annealed sample of the nonoriented electrical steel include AlN inclusions, Al2O3 inclusions, Al2O3-MnS inclusions and MgO-Al2O3-MnS inclusions.The results of corrosion behavior process showed that there are three kinds of rust spots with different morphology in the corrosion process of 50W800 test plate of non-oriented electrical steel, and the change process of rust spots with different morphology is different within 60 minutes of salt spray box corrosion.According to the analysis of corrosion process and cause of 50W800 test sample of non-oriented electrical steel, the main reason for corrosion of sample is the change of corrosion morphology caused by inclusions Al2O3, Al2O3-MnS and MgO-Al2O3-MnS.Moreover, the corrosion area caused by Al2O3-Mns inclusions above 10μm increases with the increase of corrosion time.

In view of the existing problems of the annealing furnace in Cold Rolling Silicon Steel Plant of Angang Steel Co. Ltd., the new technologies of the total radiant tube heating, low nox burners, continuous + pulse combustion control mode, increasing the number of waste heat recovery unit, the furnace roller bearing to increase heat insulation measures, etc. were used in this technocal renovation, which improved the product surface quality, reduced the nitrogen oxide index, realized the waste heat recovery, and improved the stable operation level of the reformed annealing furnace.

The silicon steel factory of Wuhan Iron and Steel Co. Ltd. has many kinds of imported welding machines with miscellaneous models, which are difficult to manage.Based on several years’ experiences in technology management of imported welding machines, the main management idea of operation stability and weld quality reliability of imported welding machine was formed, and several aspects of management ideas of the management team mode of imported welding machine, core content, technical management, field management, spare parts localization and intelligence of welding machine were introduced, which realized the reliable and stable operation of imported welding machine and reduced the occurrence of broken belt and heavy welding accidents.