Non oriented electric steel plate without corrugated fault and its making process

Abstract

Non-oriented electrical steel sheet without corrugated defects and its manufacturing method, its composition (weight percentage) is: C: .006%~0.01%, 0<Si≤2.0%, 0<Al≤0.4%, Mn≤1.0% , the rest are Fe and inevitable inclusions; the ratio of Si / C is 180-260. The manufacturing method comprises the following steps: a. continuous casting of slabs; b. heating of cast slabs, rough rolling, rough rolling passes ≤ 4 passes, rough rolling cumulative reduction rate ≥ 80%, wherein at least one pass of reduction Rolling rate ≥ 40%, rough rolling finish rolling temperature ≥ 980 ℃; c, finish rolling, among the several stands in front of the finish rolling unit, at least one stand adopts a roll with a relatively rough roll surface, and the roll surface roughness is at least ≥ 5μm; d, coiling, hot-rolled plate ≥ 710 ℃ high temperature coiling. The invention optimizes the components and the process, and the finished plate can completely eliminate the corrugated defects, omit the normalization process of the hot-rolled plate, reduce the production cost, and improve the physical properties.

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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