Hot-rolled wire rod for high-strength low-relaxation prestressed steel strand and preparation method of hot-rolled wire rod

Abstract

The invention discloses a hot-rolled wire rod for a high-strength low-relaxation prestressed steel strand and a preparation method of the hot-rolled wire rod. The hot-rolled wire rod comprises the following chemical components in percentage by weight: 0.78 to 0.82 weight percent of C, 0.21 to 0.28 weight percent of Si, 0.72 to 0.82 weight percent of Mn, 0.31 to 0.34 weight percent of Cr, 0.015 to 0.025 weight percent of V, less than or equal to 0.007 weight percent of S, less than or equal to 0.015 weight percent of P, less than or equal to 0.0035 weight percent of N, less than or equal to 0.0012 weight percent of O and the balance of Fe and inevitable impurities. The preparation method sequentially comprises the following steps of molten iron pretreatment desulfurization, molten steel smelting, deoxidation alloying, molten steel LF furnace refining, molten steel casting, steel billet heating, and a controlled rolling and controlled cooling process. The method disclosed by the invention has the characteristics of low cost, strong process applicability and controllability and the like, the produced wire rod is high in cleanliness, the content of harmful elements S and P in steel is low, and non-metallic inclusions are less than or equal to grade 2.0; and the content of sorbite in a metallographic microstructure of the steel wire rod is greater than or equal to 92%, and the steel wire rod has no network cementite, has high strength, low relaxation rate, excellent plasticity and toughness and drawing deformation capability, and effectively avoids the phenomenon of wire breakage in the drawing process when the steel wire rod is used for manufacturing prestressed steel wires, stranded steel wires and the like.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a hot-rolled wire rod for high-strength and low-relaxation prestressed steel strand and a preparation method thereof. Background technique [0002] Hot-rolled wire rods for high-strength prestressed steel strands are mainly used to make prestressed steel wires, steel strands, etc., and are widely used in bridges, airports, overpasses, power stations, dams, high-rise buildings and many other major projects. In order to bear the comprehensive effect of various loads, it is required to have high yield strength, tensile strength and toughness to prevent fracture and deformation under impact or overload; at the same time, it is also required that the steel has good processing performance during processing. The deep processing performance of the base metal has higher requirements. The SWRH82B hot-rolled wire rod as the raw material of the steel strand not only needs to ...

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Problems solved by technology

[0003] At present, in order to improve product quality, the production enterprises of steel strand SWRH82B high-wire wire rod have improved control methods and strengthened control management in the whole process of raw and auxiliary materials for steelmaking, steelmaking and steel rolling process equipment, process control technology, and production process management. Through molten iron pretreatment→top-bottom reblowing converter smelting→LF furnace refining→RH furnace vacuum refining→billet full protection casting→high-volume high-line rolling mill with reducing and sizing unit controlled rolling and controlled cooling process route production, steel added With a small amount of microalloy, the SWRH82B high-wire wire rod produced can meet the needs of users, but the production of the product has the following problems: high requirements for equipment precision, a small amount of precious microalloy added to the steel, and high production costs; in addition, the SWRH82B hot-rolled coil currently produced The strip has a high sorbite rate and is unstable, with a small amount of martensite and 1.5-3.0 grade reticular cementite structure, the reduction of area is low, and the microstructure ratio of the steel is not optimal. There are still a small amount of broken wires in the process, which restricts the use of the product

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