Indirectional electric steel plate without corrugated fault and its making process

Abstract

The indirectional electrical steel plate without corrugated fault has the components including C0.006-0.01 wt%, Si 0-2.0 wt%, Al 0-0.4 wt% and Mn not higher than 1.0 wt% except Fe and inevitable impurity, with the Si / C ratio being 180-260. Its making process includes continuously casting plate blank; hot rough rolling for not more than 4 gates with total percentage reduction not less than 80 %, at least one gate of percentage reduction not less than 40 % and finish rolling temperature not lower than 980 deg.c; finish rolling with at least one roller of roughness not lower than 5 micron; and winding at temperature not lower than 710 deg.c. The optimized components and technological process mikes the steel plate product free from corrugated fault and high in physical performance. The omitting of normalizing step results in lowered production cost.

Description

technical field [0001] The invention relates to a non-oriented electrical steel sheet manufacturing technology, in particular to a non-oriented electrical steel sheet manufacturing technology for overcoming corrugated defects. Background technique [0002] Non-oriented electrical steel sheets are mainly used to produce iron core materials for motors. The components of the non-oriented electrical steel are (percentage by weight): C<0.01%, Si+Al>1.50%, Mn<1.0%, and the rest are iron and unavoidable impurities. The continuous casting method is used to produce non-oriented electrical steel. Since the αγ phase transformation basically does not occur during the heating and hot rolling process, the huge (100) columnar grains of the cast structure cannot be obtained due to the slow dynamic recovery and recrystallization during the hot rolling process. Thoroughly broken, forming very thick deformed grains extending along the rolling direction near the center of the hot-rol...

AI Technical Summary

Problems solved by technology

However, when the low-temperature casting method is used, the continuous casting process is not easy to control, and the inclusions in the crystallizer are not easy to float up, and the number of inclusions in the continuous casting slab increases, which affects the quality of the final product

[0005] There is also the method of controlling the finishing of rough rolling (such as the special publication No. 53-2332 disclosed in the Japanese Patent Gazette), the temperature of the finishing of rough rolling is controlled to > 900 ° C, and the reduction rate of the last pass of rough rolling > 50%, Make the corrugated defects of the finished slab disappear; this not only requires high capacity of the rough rolling unit, but also the reduction rate of the last rough rolling pass is too large, which makes it difficult to control the shape of the rough rolled slab and affects the finish rolling operation

[0006] Or, adopt the method of controlling the finishing rolling temperature (such as the Japanese Patent Publication No. 62-54023 bulletin), control the finishing rolling finishing temperature > 1000 ° C, and do not spray water for cooling within 1 to 7 seconds after hot rolling, And coiling at <700°C to prevent corrugated defects; this method requires the heating temperature of the continuous casting slab to be raised to above 1250°C, which will easily cause the continuous casting slab to collapse, affect the roller conveying and generate internal cracks inside the continuous casting slab

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