Chromium-free SWRH82B high-carbon steel wire rod and production method

Abstract

The invention discloses a chromium-free SWRH82B high-carbon steel wire rod and a production method. The wire rod comprises the following components: (0.80-0.84) wt% of C, (0.15-0.30) wt% of Si, (0.70-0.80) wt% of Mn, less than or equal to 0.015 wt% of P, less than or equal to 0.010 wt% of S, less than or equal to 0.10 wt% of Cr, less than or equal to 0.005 wt% of Al and the balance of Fe. The method comprises the following steps: (1) smelting raw materials by adopting a top-bottom combined blown converter, wherein chromium is not added during smelting; (2) refining by adopting an LF (Ladle Furnace) after smelting, wherein chromium is not added during refining; (3) carrying out continuous casting on a square billet with the size of (150mm * (150-180) mm after refining; (4) heating the steel billet after continuous casting; (5) after the steel billet is heated, high-pressure water is adopted for descaling; (6) carrying out high-speed wire rod rolling after descaling; and (7) carrying out controlled cooling by adopting a Stelmor air cooling line after rolling. According to the method, ferrochrome is not added into a converter and a refining furnace, steel billets are evenly heated, chemical component homogenization is promoted, the cooling speed before air cooling line phase change is increased to 10 DEG C / s or above from 7.5 DEG C / s, the sorbite proportion reaches 90% or above, steel billet element segregation is controlled, the martensite content and grade are reduced, and meanwhile it is guaranteed that the strength and area shrinkage of the wire rod meet the quality requirement.

Description

technical field [0001] The invention belongs to the field of steel production and manufacturing, and in particular relates to a chromium-free SWRH82B high-carbon steel wire rod and a production method. Background technique [0002] SWRH82B high-carbon steel wire rod is generally used in the production of high-strength metal products such as prestressed steel wire and steel strand. It is mainly used to make prestressed steel strand through drawing and stranding. Prestressed steel strand is widely used in bridges, In the fields of construction, water conservancy, energy and geotechnical engineering, prestressed steel strands need to have the characteristics of high strength, low relaxation and high toughness. [0003] However, the φ12.5 specification SWRH82B high carbon steel wire rod is prone to the problem of brittle fracture during drawing. The main reason is that the severe Mn and Cr segregation and aggregation in the center lead to the abnormal structure of martensite in ...

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Problems solved by technology

[0003] However, the φ12.5 specification SWRH82B high carbon steel wire rod is prone to the problem of brittle fracture during drawing. The main reason is that the severe Mn and Cr segregation and aggregation in the center lead to the abnormal structure of martensite in the product, which in turn leads to the release of the product. Or the problem of broken wires in the drawing stage seriously affects the quality stability and production efficiency of the product. The higher the cooling rate of the critical formation of martensite, the less likely it is to form martensite during cooling

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