It is a frequently observed quality problem for new producers that the low temperature heating and subsequent nitriding grain oriented silicon steel products show a full abnormally grown grain structure but with a low magnetic property and its reason and solution are crucial to reduce production costs. In this work the products with above-mentioned phenomenon in two groups of grain oriented silicon steels were analyzed by determining their corresponding grain orientations in primary recrystallized sheets, in the interrupted samples during secondary recrystallization annealing including matrix grains and secondary grains and detecting their secondary recrystallization temperatures. Results showed that the reason for the decrease in magnetic properties lay in the higher scattering of Goss orientation mainly towards to {110}<227> which was related with a smaller average grain size of primary recrystallized sheets leading to low starting secondary recrystallization temperature by about 50 ℃. The earliest secondary grains showed large orientation scattering to Goss orientation. The difference in magnetic properties of the two group sheets were not related to their starting secondary recrystallization temperature, but to their degree in orientation scattering, which were ascribed to the slight differences in primary recrystallization textures and inhibitors as well as the turbulence in key elements contents.

In recent years, grain oriented electrical steels are developing toward low iron loss and thin gauge products, which increase the difficulty of subsequent product shearing. In this paper, the shearing characteristics of thin gauge grain oriented electrical steels were analyzed, and the relevant researches were summarized. According to the EVI experience of grain oriented electrical steels in Baosteel, the common shearing defects of thin gauge grain oriented electrical steels were analyzed.

In view of the water print defects on the surface of common oriented silicon steel during the secondary pickling process, the defect types were determined by means of the analysis of the microcosmic characteristics of the defects and the elemental analysis of the energy spectrum in the defect area, and the causes were determined according to the analysis of the production correlative factors. The results showed that the roughness difference on the surface after secondary pickling was the direct cause of hydrographic defects. Production correlation analysis showed that the residual amount of iron oxide in the adsorbed area of corrosion inhibitor was related to the concentration of corrosion inhibitor in acid solution. The defect rate of the pickling water imprint was reduced from 18.73 % to 0 % by draining acid tank and circulating tank and reducing acid temperature at the initial stage of pickling plan.

The effect of annealing temperature after cold rolling on the microstructure, texture evolution and magnetic properties of 0.5 % Si non-oriented silicon steel was investigated under laboratory conditions. The results showed that the increase of the annealing temperature from 675 ℃ to 725 ℃ was conducive to the increase of the recrystallization rate , and the recrystallization was completed at 725 ℃. The average grain size was increased from 18.2 μm to 40.2 μm with the increase of annealing temperature from 725 ℃ to 850 ℃. Therefore, P1.5/50 was decreased from 10.4 W/kg to 4.5 W/kg with the increase of annealing temperature from 675 ℃ to 850 ℃. When the annealing temperature increased from 675 ℃ to 725 ℃, the magnetic induction increased gradually due to the increase of recrystallization rate. By contrast, with the increase of annealing temperature from 725 ℃ to 850 ℃, the volume fraction of {111} grains was increased from 35.8 % to 40.4 %, and the beneficial {001} and that of the Goss grains was decreased from 14.8 % to 12.8 %, thus reducing B50 from 1.76 T to 1.74 T. Therefore, It is necessary to select the appropriate annealing temperature to obtain the properties of lower iron loss and higher magnetic induction.

As an important iron based raw material in industrial production, pure iron has been widely used at home and abroad because of its excellent performance. Research institutions and production enterprises at home and abroad attach great importance to the development of pure iron purification. In this paper, the regulations of different types of pure iron in China were given, the main smelting methods of industrial pure iron in production and the research results of ultra-high purity iron preparation by researchers at home and abroad were introduced. The technological processes of large-scale production of industrial pure iron by domestic enterprises such as Tisco, Ansteel and Xingtai Iron and Steel Co., Ltd. were analyzed, and the industrial pure irons produced by Chinese enterprises and JFE company in Japan were compared and analyzed. The development trend of high purification of pure iron was pointed out. With the development of electroslag remelting technology and space electrophoresis purification technology, the high purification of pure iron has injected new vitality.

The relationship between strip shape and strip deviation was obtained by analyzing the force of rolled hard strip steel running on the roll surface of the annealing line and combining with the actual silicon steel sheet shape cold rolled on the six-high reversible rolling mill of Masteel. And then according to the actual situation of silicon steel production line in a steel mill and the correlation analysis between the sheet shape and the deviation, effective measures to reduce the deviation of the annealing line were formulated. These measures were playing a key role in deviation control combined with the roll system reform of the annealing line and the improvement of the deviation correction ability.

Furnace pressure is an important control index of annealing furnace. Furnace pressure fluctuation will have a significant impact on the quality and performance of products. The pressure control of the existing continuous annealing furnace generally adopted a conventional PID control method, which caused the traditional continuous annealing furnace pressure could not take into account the requirements of stability and rapidity at the same time. A new control method of furnace pressure control model was adopted, which took the set value and actual value of furnace temperature, burner power, gas and air flow in the furnace area as the input, and used the multivariable predictive control algorithm to calculate the current optimal exhaust fan speed, so as to realize the control of furnace pressure stably and improve the control accurately.

Based on ibaPDA system, the intelligent judgment model of piston cylinder was practically realized by analyzing the state of silicon steel line piston cylinder with UML, data cleaning of digital signals, and establishment of relative judgment standards with box diagram, which accumulated experience for the development of subsequent models.