Method for producing hot rolled steel strip for automotive frame

Abstract

The invention discloses a method for producing a hot rolled steel band used for an automotive frame, comprising the following steps: the pretreated liquid iron is smelt conventionally in a top and bottom combined-blowing revolving furnace, argon is blown at the bottom of the furnace in the whole process, the contents of carbon, phosphorus, silicon and manganese at the terminal of the liquid iron are controlled; the liquid iron discharged from the furnace is refined by an LF furnace, argon is blown to the liquid iron and is stirred and decarbolized at the same time of blowing the argon at the bottom of the LF furnace in the whole process, the liquid iron is subjected to microalloying by adding vanadium, titanium, niobium alloy or niobium and titanium alloy, the content of the microalloy in the liquid iron is controlled to between 0.15 and 0.20 percent, the refined liquid iron is continuously cast into a casting blank through a CSP sheet billet conticaster, the casting blank is soaked in a roller-hearth type soaking furnace and is rolled initially through a vertical miller as well as is sent to a finishing mill set to be rolled, the rolling force of each stander and the finishing temperature of the steel band are controlled, and the hot rolled steel band is cooled through a laminar flow and is cut by a pair of flying shears as well as is wound into a steel coil through a recoiling machine. The produced steel band in 510 L and 590 L or 610 L used for the automotive frame has excellent comprehensive mechanical property, and technique processing and welding performances, can be taken as the automotive frames of a light truck, a medium truck and a heavy truck as well as an agricultural automobile and has remarkable benefits.

Description

technical field [0001] The invention relates to a method for producing hot-rolled steel strips, in particular to a method for producing 510L, 590L or 610L hot-rolled steel strips for automobile girders by using a CSP thin slab continuous casting and rolling process. Background technique [0002] Compared with the traditional hot-rolled wide-band steel production, thin slab continuous casting and rolling technology combines less investment, short construction period, high efficiency and low cost, and has recently developed rapidly in my country. [0003] The thin slab continuous casting and rolling production line is a "Compact Strip Production" equipment imported from the German SMSD consortium, with an annual designed production capacity of 2.5 million tons. [0004] There have been many domestic reports on the production of hot-rolled steel strips for automobile beams using the CSP process. For example, Baotou Steel uses the converter-CSP process to develop 590MPa grade C-...

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Problems solved by technology

[0007] However, the microalloyed steel of C-Mn-Nb-V-Ti is adopted, and its C≤0.06%, Nb+V+Ti≤0.15%, S≤0.008%, through the pure steel smelting and full protection based on the converter→CSP process The casting technology makes [O] ≤ 30ppm, [N] ≤ 40ppm, [H] ≤ 1.0ppm, inclusion denaturation treatment [Ca] / [Al] ≥ 0.1 and the CSP process with the same technical characteristics to produce 590L automobile frame steel. not found

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