Smelting process for production of grade II hot-rolled reinforced bar

Abstract

The invention relates to a smelting process for production of a grade II hot-rolled reinforced bar, which belongs to the technical field of metallurgy. A technical scheme provided by the invention is as follows: through usage of a vanadium extraction-steelmaking duplex process, the grade II hot-rolled reinforced bar is produced by using molten iron containing vanadium and silicon-manganese alloy as main alloying raw materials; according to the process, production cost of the bar is reduced by increasing the content of V in the bar and properly reducing elements consisting of Mn and Si in the grade II hot-rolled reinforced bar on the base of ensuring performances of the grade II hot-rolled reinforced bar; the elements consisting of Mn and Si are mainly from the silicon-manganese alloy, the element C is mainly from C at a steelmaking terminal point and C brought by the molten iron containing vanadium, and the element V is mainly from residual vanadium at the steelmaking terminal point, V brought by the molten iron containing vanadium and V of V2O5 in final slag of a reduction converter. With the process provided by the invention, performances of the grade II hot-rolled reinforced bar are guaranteed, production cost of the grade II hot-rolled reinforced bar is reduced, a variety of performances of the grade II hot-rolled reinforced bar are guaranteed without passing through water, and quality of the bar is ensured.

Description

technical field [0001] The present invention relates to a kind of smelting process of producing II grade hot-rolled rebar, belongs to metallurgical technical field. Background technique [0002] At present, Class II hot-rolled threaded steel bars (HRB335) are widely used in the construction field. The national standards have made corresponding regulations on the weight percentages of the chemical components of steel bars, which are C≤0.25%, Si≤0.80%, Mn≤ 1.60%, P ≤ 0.045%, S ≤ 0.045%, Ceq ≤ 0.52%. At the same time, corresponding regulations have been made on the performance requirements of steel bars, which are yield strength ≥ 335MPa and tensile strength ≥ 455MPa, that is, in the grade II hot-rolled rebar In production, it is necessary to meet the requirements that each main element cannot exceed its upper limit, and at the same time meet its performance requirements. Since the performance requirements of grade II hot-rolled threaded steel bars are lower than those of oth...

AI Technical Summary

Problems solved by technology

With the rising price of raw materials and increasingly fierce market competition, the profit level of Class II hot-rolled rebars has gradually declined. In order to reduce the production cost of Class II hot-rolled rebars, some enterprises have adopted re-piercing water technology in the production process of rebars. By adopting this process, the Mn content of steel bars can be reduced by 0.30-0.40%, which can greatly reduce production costs. However, this process has the problem of surface corrosion of steel bars, which seriously affects the quality of steel bars, so this process has been banned.

If the water penetration process is not used to reduce the Mn content in the steel, it is necessary to add precious and rare elements such as V and Nb to strengthen the performance, and the alloys containing these elements are expensive and the cost is high, and the cost of the enterprise is affected.

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