A kind of high-strength bridge cable steel with pearlite lamella spacing less than 150nm and production method

Abstract

The invention relates to a high-strength bridge cable steel with pearlite inter-lamellar spacing smaller than 150nm. The high-strength bridge cable steel with pearlite inter-lamellar spacing smaller than 150nm is prepared from the following chemical components by weight percentage: 0.95 to 1.0 percent of C, 0.8 to 1.0 percent of Si, 0.3 to 0.6 percent of Mn, less than or equal to 0.025 percent of P, , less than or equal to 0.025 percent of S, 0.030 to 0.045 percent of V, 0.025 to 0.035 percent of Als, 0.010 to 0.03 percent of Ti, 0.2 to 0.4 percent of Cr, 0.2 to 0.3 percent of Ni, 0.02 to 0.03 percent of Nb and 0.007 to 0.010 percent of N. Production processes comprise molten iron desulphurization and converter smelting; argon blowing at argon blowing station; LF refining; RH treatment; steel taping and continuous casting; cogging; heating; rolling; air cooling to room temperature; secondary heating; high-speed rolling; reducing-sizing rolling; spinning; cooling, air cooling to room temperature. The pearlite inter-lamellar spacing of the high-strength bridge cable steel is smaller than 150nm, the alloy recovery rate is high, the steel purity is high, the tensile strength is greater than or equal to 2000MPa, and the tensile strength can be finally improved by 15 percent under the situation of not influencing elongation.

Description

technical field [0001] The invention relates to a steel for bridges and a production method thereof, in particular to a high-strength bridge cable steel with a pearlite lamellar distance less than 150nm and a production method thereof. Background technique [0002] With the development of bridges, the preferred bridge types for long-span bridges are generally cable-stayed bridges and suspension bridges. The development of cable-supported bridges has put forward higher performance requirements for the key raw material of bridge cables - galvanized steel wire, that is, under the principle of continuously improving the strength level and satisfying other mechanical properties, the amount of materials should also be saved , to reduce production costs. However, the improvement of the strength level will significantly reduce a series of indicators such as toughness and surface shrinkage, which will affect the comprehensive performance of bridge cable steel. In particular, it is ...

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Problems solved by technology

Although the document has a stable tensile strength of ≥2000MPa, a torsion value of ≥15 times, and no wire breakage due to quality problems in cold drawing, there is not enough nitrogen-fixing elements in it, which makes the brittleness larger and leads to elongation. It does not meet the requirements; there is a large amount of ferrite in the metallographic structure, which causes a large deviation of the lamellar spacing. After analysis, it is caused by uneven cooling; there is decarburization on the surface, which affects the use

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