Rolling method of high-grade non-oriented silicon steel

Abstract

The invention relates to a rolling method of high-grade non-oriented silicon steel. Through four-time rolling, reduction ratios are increased so as to increase deformation heat of strip steel, so thata rolling temperature of the strip steel is increased, and a temperature of an incoming material is controlled to reach 55 DEG C to 60 DEG C; the scheme of the four-time reduction ratios comprises that the reduction ratio for the first time is 37 percent to 41 percent, the reduction ratio for the second time is 36 percent to 39 percent, and the reduction ratio for the third time is 34 percent to37 percent; rolling force for the four times is respectively controlled as follows: 4750kN to 5000kN, 4600kN to 5000kN, 4400kN to 4600kN and 3900kN to 4200kN; and unit tension adjustment on rolling atthe previous two times is carried out. The rolling method of the high-grade non-oriented silicon steel disclosed by the invention has the advantages that the rolling times are simplified, the trend of edge cracking of an edge part of the strip steel is reduced, and production of double -rib wave is reduced.

Description

technical field [0001] The invention belongs to the field of cold-rolled strip rolling, and in particular relates to a rolling method of non-oriented high-grade steel. Background technique [0002] Non-oriented high-grade silicon steel, such as: 35AW230, 35AW210 and other strip steels have high silicon content, and the Si content is as high as 3.10%, resulting in high hardness, high brittleness, and difficult deformation of the product, which makes the rolling process of the 20-high rolling mill more difficult. When rolling these high grades, the broken strip rate is very high, and the finished product rate is extremely low. There are mainly the following problems: [0003] 1. In the first pass, because the strip steel is too brittle, it is prone to brittle fracture during the threading process, resulting in failure to thread the strip and scrap it; [0004] 2. After the first pass, there is a large edge crack, which makes the second pass unable to be rolled and scrapped; ...

AI Technical Summary

Problems solved by technology

[0002] Non-oriented high-grade silicon steel, such as: 35AW230, 35AW210 and other strip steels have high silicon content, and the Si content is as high as 3.10%, resulting in high hardness, high brittleness, and difficult deformation of the product, which makes the rolling process of the 20-high rolling mill more difficult.

When rolling these high grades, the broken strip rate is very high, and the finished product rate is extremely low. There are mainly the following problems:

[0003] 1. In the first pass, because the strip steel is too brittle, it is prone to brittle fracture during the threading process, resulting in failure to thread the strip and scrap it;

[0004] 2. After the first pass, there is a large edge crack, which makes the second pass unable to be rolled and scrapped;

[0005] 3. In the second pass, due to the high brittleness of the strip steel, it is prone to strip threading brittle fracture, resulting in the failure to thread the strip and scrap it, or the strip is broken due to edge cracks during the rolling process

[0006] 4. Edge cracks appear during the third and fourth rolling passes, and it is necessary to go to the tailor welding unit for edge trimming and return to the rolling mill to continue rolling. The production efficiency is low and the yield is affected

[0007] After several tests, the yield of 35AW230, 35AW210 and other non-oriented high-grade silicon steel plates is only about 60%, far below the target requirements