Hot-rolled wire rod for manufacturing high-strength steel strand for intelligent strong grid and production method thereof

Abstract

The invention discloses a hot-rolled wire rod for manufacturing a high-strength steel strand of a strong and smart grid and a production method of the hot-rolled wire rod, and relates to a hot-rolled wire rod for manufacturing a high-strength steel strand of a grid. Chemical composition of the hot-rolled wire rod is composed of the following substances in percentage by weight (%): 0.70-0.74% of C, 0.17-0.37% of Si, 0.70-0.80% of Mn, 0.07-0.14% of Cr, less than or equal to 0.025% of P, less than or equal to 0.025% of S, less than or equal to 0.30% of Ni, less than or equal to 0.25% of Cu and the balance of Fe. According to the phi6.5mm hot-rolled wire rod produced by the method disclosed by the invention, tensile strength is 1120-1200Mpa, area reduction is 40-50% and percentage of elongation is more than or equal to 18%. The hot-rolled wire rod disclosed by the invention has the advantages that process equipment and parameter setting are reasonable, longstanding problems are solved and product quality is improved; the wire rod is drawn into a steel wire to enhance strength, and a loading bearing capacity of a steel strand processed from the steel wire is greatly improved; and the hot-rolled wire rod is easy to draw, and capable of avoiding an intermediate heat treatment process and saving energy.

Description

technical field [0001] The invention belongs to hot-rolled wire rods, in particular to a hot-rolled wire rod for manufacturing high-strength steel strands for strong power grids and a production method thereof. Background technique [0002] The hot-rolled wire rods used to make steel strands for power grids are mainly 70 steel Φ6.5 hot-rolled wire rods produced according to the national standard GB / T 4354-2008 "High-quality Carbon Steel Hot-Rolled Wire Rods". The actual hot-rolled wire rod has a tensile strength of 980-1080MPa, an elongation of 14-18%, and an area shrinkage of ≥30%, which can only be used to produce steel strands for ordinary power grids. The performance requirements of the hot-rolled wire rod used to manufacture high-strength rare-earth galvanized steel strands for intelligent strong grids are: the physical tensile strength is 1120-1200MPa, the elongation rate is ≥15%, and the area reduction rate is ≥35%. The invention patent of "High Carbon Steel Wire Rod...

AI Technical Summary

Problems solved by technology

Although the standard stipulates the upper limit of chromium content, chromium is not added in actual production, because after adding chromium to 70 steel, the wire rod produced according to the normal 70 steel controlled rolling and controlled cooling process will increase in strength and decrease in plasticity, sometimes producing martensite , bainite and other abnormal structures, resulting in brittle fracture during the drawing process of the user, and even brittle fracture during the bundling process of the wire rod

Therefore, the chromium-free 70 steel wire rod produced by converter smelting, LF furnace refining, billet continuous casting, high-speed rolling mill rolling, and conventional controlled cooling process has a tensile strength of 980-1080 MPa and an elongation of 14-18. %, area shrinkage ≥ 30%, unable to meet the high requirements of users

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