Manufacture method of high-silicon aluminum content non-oriented silicon steel strip

Abstract

The invention discloses a manufacture method of a high-silicon aluminum content non-oriented silicon steel plate cold-rolled sheet, belonging to the field of material preparation and comprising the following components in parts by mass: 0.003 percent of C, 3.20 percent of Si, 0.60 percent of Mn, 0.008 percent of P, 0.001 percent of S, 1.10 percent of Al, 0.002 percent of Ti, not more than 0.03 percent of Ni, not more than 0.03 percent of Cr, not more than 0.03 percent of Cu and the balance of Fe or trace elements and unavoidable impurities. The manufacture method comprises the steps of: smelting in a converter, refining in a vacuum furnace, continuous-casting, thermal-rolling, normalizing, scouring and trimming, once-cold-rolling, intermediate-annealing, secondary-annealing, and annealing. A continuous casting blank is rolled into a strip, a hot-rolled strip enters a souring line for souring and trimmed on line after the scouring is finished; and the trimmed steel strip is subjected to normalization and annealing on a normalizing line and finally rolled and annealed. According to the invention, a stress concentrated part caused by trimming of the hot-rolled strip is released through the normalizing process, so that internal reasons causing cold rolling edge crack are eliminated and a cold rolling edge gap is completely removed.

Description

Technical field: [0001] The invention belongs to the field of material preparation. The high silicon and aluminum content refers to non-oriented silicon steel with a silicon and aluminum content greater than 4.0%, and its grade refers to 35TW210 and 35TW230. A method for edge cracking of silicon steel sheets during cold rolling. Background technique: [0002] Cold-rolled silicon steel is an important soft magnetic material, mainly used in the manufacture of motor cores, E-I sheets, etc. Its main technical indicators are iron loss and magnetic induction, which are the main basis for classifying low-grade and high-grade cold-rolled silicon steel. The two grades 35TW210 and 35TW230 are high-grade products in non-oriented silicon steel, and 35TW210 is the highest grade specified in the international electrical steel standard. Due to its complex manufacturing process, high technical difficulty, and high equipment requirements, only a few top foreign companies (NSC and JFE) ca...

AI Technical Summary

Problems solved by technology

[0017] Patent "A Manufacturing Method for Preventing Edge Cracks in Low-Carbon Cold-rolled Ultra-thin Strip Steel", publication number: CN101811134A, the idea is to adjust the temperature of the hot-rolled process The system and rolling reduction distribution are optimized to achieve the purpose of eliminating cold-rolled edge cracks; this patent is mainly aimed at low-carbon steel with high plasticity, and the cause of edge cracks in high-grade non-oriented silicon steel is not in hot rolling. Therefore, the patent has no practical reference value

[0018] 35TW210 grade non-oriented silicon steel, the sum of Si and Al content reaches 4.3%, but with the increase of Si and Al content, the strength of the steel strip itself increases, and the plasticity Sharply reduced, cold working is difficult, and defects such as strip edge cracks are prone to occur

The above two methods can effectively eliminate the shear stress, but this method requires equipment modification, long construction period and large investment, so it is not feasible at this stage

[0021]In order to improve the magnetic properties, high-grade silicon steel is usually subjected to normalizing annealing before cold rolling, and annealing can promote the recovery and recrystallization of the internal structure of the material, and then the shear The shear stress is released, but the problem is that the edge trimming process is located after annealing, which does not achieve the purpose of stress relief