Bridge cable steel with tensile strength being greater than or equal to 2500 MPa and production method

Abstract

The invention provides bridge cable steel with the tensile strength being greater than or equal to 2500 MPa. The bridge cable steel comprises chemical components of, by weight, 1.21-1.25% of C, 1.1-1.5 % of Si, 0.2-0.5 % of Mn, no more than 0.01% of P, no more than 0.01% of S, 0.07-0.09 % of Cr, 0.06-0.08% of Ti, 0.16-0.20% of Al, 0.005-0.009 % of N, 0.001-0.0015 % of B and 0.002-0.005 % of Zr. Aproduction method comprises the steps that hot metal pretreatment is conducted; converter smelting is conducted; RH vacuum treatment is conducted; continuous casting is conducted to form a billet; thecasing billet is cut through flame in the longitudinal direction after indoor stacking slow cooling is conducted; the casting billet is heated; the casting billet is initially rolled to small squarebillets; the square billets are heated after stacking slow cooling is conducted; high-speed rolling is conducted; laying is conducted; and the square billets are cooled through air to the room temperature. According to the bridge cable steel with the tensile strength being greater than or equal to 2500 MPa and the production method, the strength reaches more than 2500 MPa after the square billetsare subjected to drawing, galvanizing and stabilizing treatment, the condition that the number of torsions is not less than 12 times is simultaneously met, and the bridge cable steel can meet the construction demand of a large bridge with the bridge span being greater than 1100 meters.

Description

technical field [0001] The invention relates to a wire rod and a production method thereof, belonging to a wire rod for a bridge cable and a production method thereof, in particular to a wire rod for a bridge cable with a tensile strength ≥ 2500 MPa and a production method thereof. Background technique [0002] Bridge is a key node project of infrastructure, which is difficult to construct and requires high engineering requirements. It represents the highest level of engineering construction, design and manufacturing, and material development in a country or even an era. The design of modern bridges is scientific and reasonable, making full use of the tensile properties of steel and the compressive properties of concrete, and the entire bridge deck is lifted by bridge cables. [0003] As an important load-bearing part of modern bridges, bridge cables directly determine the safety, span, and engineering construction feasibility of bridges. For example, in busy waterways or ar...

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Problems solved by technology

[0008] The Chinese patent publication number is CN102936688A, which relates to a wire rod for bridge cables with a tensile strength ≥ 2000 MPa and a production method. The actual strength of the patented steel wire is less than 2100 MPa, and the C content is as high as 0.95-1.2%. The higher content of C ensures The strength of the steel wire is improved, but the production is difficult and if the production control is not proper, it is often accompanied by large fluctuations in the torsion value, which is not conducive to the control of the quality of the steel wire and the safety of the bridge; at the same time, the low content of Si in this document will inevitably lead to Large losses and uncontrolled fluctuations

Moreover, the patent does not describe the converter, vacuum, refining and other processes in the steelmaking process, and the homogeneous production of high-carbon steel has always been a difficult point in the industry, so it is difficult to guarantee the stable production of the patented steel

[0009] The Chinese Patent Publication No. CN105112807 relates to a high-strength bridge cable steel with a pearlite interlamellar spacing of less than 150nm and a production method. The final steel wire strength of this document is less than 2100MPa. In order to pursue an extremely fine interlamellar spacing, this patent carries out low-temperature rolling (spinning temperature 785 ~ 810 ℃), but too small sheet spacing will cause troostite in the steel (pearlite is divided from large to small according to the distance of the photo: pearlite, sorbite, troostite), resulting in The increased brittleness of steel not only makes production control difficult and poor in stability, but also affects the safety of bridges

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