Hot-rolled steel wire rod for large bridge cable rope zinc-plated steel wire over 2000 MPa level and production method

Abstract

The invention relates to a hot-rolled steel wire rod for a large bridge cable rope zinc-plated steel wire over the 2000 MPa level. Chemical components of the steel wire rod comprise, by weight percentage, 0.90-1.10% of C, 0.20-0.60% of Si, 0.30-0.90% of Mn, smaller than or equal to 0.010% of P, smaller than or equal to 0.005% of S, 0.10-0.40% of Cr, 0.010-0.070% of Al, 0.02-0.15% of V, smaller than or equal to 0.05% of Cu, 20-40 ppm of Ca, 20-90 ppm of N and the balance Fe and inevitable residual elements. The content of sorbite texture of the steel wire rod is larger than or equal to 95%. Thethrough ring range of the tensile strength is smaller than or equal to 70 MPa (uniformity). After the steel wire rod is subjected to drawing and zinc plating, the tensile strength of the zinc-platedsteel wire is larger than or equal to 2000 MPa, and the number of torsions is larger than or equal to 12. According to the technical flow of the steel wire rod, pretreatment of molten iron is carriedout, steel is smelted through a converter or an electric furnace, LF refining is carried out, RH degassing treatment is carried out, continuous casting of 390*510 cogged ingot is carried out, a blankis reheated, the blank is rolled, the surface of an intermediate billet is subjected to finishing, the intermediate billet is reheated, the intermediate billet is rolled, the steel wire rod is subjected to EDC water bath toughening treatment, and the steel wire rod is collected and packed.

Description

technical field [0001] The invention belongs to the technical field of steel wire production, and more specifically relates to a hot-rolled wire rod for galvanized steel wires of ≥2000MPa grade high-strength bridge cables and a production method thereof. Background technique [0002] The data shows that for every 100MPa increase in the strength of the bridge cable steel wire, its own weight can be reduced by 10%, the cable diameter is correspondingly reduced, and the windward resistance is correspondingly reduced, thereby reducing the influence of the bridge on the wind force and direction. [0003] The data shows that for every 100MPa increase in the strength of the bridge cable steel wire, its own weight can be reduced by 10%, the cable diameter is correspondingly reduced, and the windward resistance is correspondingly reduced, thereby reducing the influence of the bridge on the wind force and direction. [0004] With the continuous advancement of iron and steel enterprise...

AI Technical Summary

Problems solved by technology

Due to the low cooling rate of the wire rod by the air-cooling process, the sorbite content of the structure is below 90%, the tensile strength of the wire rod is very poor at about 100MPa, and the upper limit of the production specification can only reach Φ13.0mm, which is in line with galvanized steel wire. The wire rod required by the index can only meet the level of 1860MPa, and there is no domestic example of online mass production of wire rod at the level of 2000MPa; the use of online air cooling of wire rod + offline salt bath (or lead bath) heat treatment process of wire rod requires the The wire rod is air-cooled to room temperature, and then the wire rod is laid out into a straight line into the heating furnace for re-austenitizing heating. After being released from the furnace, it is cooled in a salt bath or a lead bath. This process consumes a lot of energy, has a great impact on the environment, and has low production efficiency. Does not meet the low energy consumption and green environment-friendly production process advocated by the state

[0007] At present, the patent information publicly published in China includes: Chinese patent publication number CN 104624680A involves the production of off-line EDC. The steel wire used for rope making has not been practically applied to the production of galvanized steel wire for bridge cables

[0008] The patent publication No. CN 102719643A involves quickly placing hot-rolled wire rods into lead tanks or salt tanks for sorbitization of wire rods. The cooling medium for wire rods is lead liquid or salt liquid, which is more corrosive to equipment. It is large and pollutes the environment to a certain extent. The wire rods produced are mainly used to manufacture steel wire ropes, and have not been practically applied to the production of galvanized steel wires for bridge cables.

The production process is that the continuous casting slab is rolled into a wire rod, and the wire rod is reheated and austenitized and then heat treated in an off-line salt bath. The production cost is high and the production efficiency is low.

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