Manufacturing method of hot rolled strip steel of hypereutectoid spheroidized pearlite structure

Abstract

The invention relates to a manufacturing method of hot rolled strip steel of a hypereutectoid spheoidized pearlite structure. The technological process comprises the steps that billet check is conducted, specifically, the billet is fed into a furnace to be heated to 1,000-1,150 DEG C; rough descaling, namely rough rolling is conducted; fine descaling, namely finish rolling is conducted; the finish rolling outlet temperature is controlled below the Acm line; the cooling speed of the strip steel is controlled after finish rolling is completed, and the strip steel curls at the temperature of 710-730 DEG C; and the strip steel is collected, packaged, then fed into a holding furnace for heat preservation for 1-2 hours at the temperature of 700-710 DEG C, and finally discharged from the furnace to be air-cooled. According to the manufacturing method of the hot rolled strip steel of the hypereutectoid spheoidized pearlite structure, the strip steel of the spheoidized pearlite structure is directly provided for a client, spheroidizing annealing is not needed by the client any more, the problem that since the client uses strip steel of different manufacturers and different batches, large difference exists in chemical composition and structure, the annealing structure is non-uniform, spheroidizing is incomplete, and products of a downstream client are instable are solved, and the shortcomings that in the prior art, the energy source is wasted, equipment investment and production cost is increased and the environment is polluted are overcome.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and in particular relates to a method for producing hypereutectoid steel spheroidized pearlitic strip steel with a carbon content of more than 0.9% through controlled rolling heat preservation spheroidizing annealing. Background technique [0002] Hypereutectoid steel, after hot rolling, forms flaky pearlite + cementite structure, high strength and high hardness. Downstream users have to go through cold rolling before use, the purpose is to clean the surface, eliminate surface defects, and improve the thickness accuracy of the strip. Generally, the process of downstream customers is: pickling - spheroidizing annealing - cold rolling (to the target thickness) - cutting - finished product. The spheroidizing annealing time is long, generally more than 10 hours. The cost is high, and the annealing cost per ton is about 150 yuan. Since the steel strips purchased by customers are mostly from d...

AI Technical Summary

Problems solved by technology

The cost is high, the annealing cost per ton is about 150 yuan

Since the steel strips purchased by customers are mostly from different manufacturers and different batches, the chemical composition and structure vary greatly, which may easily lead to poor uniformity of the structure after annealing, and generally cannot be completely globalized, which will cause unstable product performance of downstream customers and seriously Affect production and use

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