Method for manufacturing cold-rolled orientation-free electrical steel

Abstract

A method for manufacturing cold-rolled non-oriented electrical steel, comprising the following steps: a) continuous casting of slabs, molten steel is continuously cast into slabs with a thickness of 120-170 mm at a casting speed of 2-3 m / min; b) hot-rolled, the slabs are directly Hot rolling or hot rolling heated to 900-1150°C, hot-rolled slab thickness to 0.8-4mm, final rolling temperature 800-950°C, coiling temperature 500-900°C; c) cold rolling, annealing or No annealing treatment, after pickling, go through primary cold rolling or secondary cold rolling with intermediate annealing to the target thickness, and implement final annealing to produce non-oriented electrical steel. In the present invention, under the condition of not adopting electromagnetic stirring, ordinary superheated continuous casting is adopted to make the non-oriented silicon steel with high silicon content in ultra-low carbon have more than 30% equiaxed crystals, so as to ensure that corrugated defects do not occur in the finished board; realize low-temperature heating And higher final rolling temperature, high recrystallization ratio of hot-rolled sheet, coarse grain, good magnetic properties of finished sheet, and low cost.

Description

technical field [0001] The present invention relates to a method for manufacturing non-oriented electrical steel. Background technique [0002] The traditional continuous casting-hot rolling production line is the production method used by most iron and steel plants to produce cold-rolled non-oriented electrical steel products. The output can reach 3 million tons to 4 million tons). [0003] The traditional continuous casting to produce non-oriented silicon steel is carried out under the conditions of continuous casting casting speed of 0.8-1.5m / min and casting slab thickness of 210mm-250mm. According to the design of this process, the following problems exist in the production of non-oriented electrical steel: [0004] 1. Under normal continuous casting superheat conditions (15°C ~ 40°C), due to the low casting speed, the solidification time is very long, columnar for electrical steel with a C content of less than 50ppm and a Si content of 1.5% to 2.5%. The proportion of...

AI Technical Summary

Problems solved by technology

The production process is complicated and the cost is high

[0005] 2. Continuous casting with low superheat (<15°C) can also increase the proportion of equiaxed grains in non-oriented electrical steel with high silicon content in ultra-low carbon, but the temperature management between converter-refining-continuous casting is very difficult, and molten steel is in The temperature of the crystallizer is very low, the viscosity increases, it is very difficult for the inclusions to float up, and the proportion of inclusion defects in the finished plate increases

[0011] iii. Because the slab is thin and the drawing speed is fast, it is impossible to produce other varieties with high surface grade requirements, such as automobile outer panels, etc.