Steel for 700Mpa-grade hot-rolled wheel and preparation method of steel

Through the design of low-carbon and low-silicon medium manganese composition and controlled rolling and cooling technology, the problems of high alloy cost, poor welding performance and fatigue performance of 700Mpa hot-rolled wheel steel are solved, and high-strength and low-cost wheel steel are achieved, with good welding performance and processing performance.

CN120384242APending Publication Date: 2025-07-29TANGSHAN IRON & STEEL GROUP +2
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Patent Information

Application Number
CN202410698254.9
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Priority Date
2024-01-26
Filing Date
2024-05-31
Publication Date
2025-07-29

AI Technical Summary

Technical Problem

In the prior art, when preparing steel for 700Mpa grade hot rolled wheels, there are problems such as high alloy cost, poor welding and fatigue performance, and difficult surface quality control, especially high alloy cost and fluctuations in the performance caused by improper design of Ti and Si content.

Method used

The low-carbon and low-silicon medium manganese composition system is adopted to control Si content ≤0.10% and Ti content <0.020%. Through a reasonable controlled rolling and cooling process, including controlling the finish rolling temperature at 980-1010℃ and high-cooling speed cooling, refining the structure, ensuring that the microstructure is ferrite + pearlite + bainite, with a grain size of ≥14, and a strip-shaped structure ≤1.

Benefits of technology

It is achieved without adding expensive alloy elements, obtaining yield strength ≥500MPa, tensile strength ≥680MPa, elongation >18%, excellent welding and processing performance, good surface quality and fatigue performance, and reducing alloy cost.

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Abstract

The invention discloses 700Mpa-grade hot-rolled wheel steel and a preparation method thereof, and belongs to the technical field of metallurgy. The steel for the wheel comprises the following chemical components in percentage by mass: less than or equal to 0.1% of C, 0.05-0.10% of Si, less than or equal to 1.65% of Mn, less than 0.015% of P, less than 0.005% of S, less than 0.060% of Nb, less than 0.020% of Ti, less than 0.03% of Cr, less than 0.045% of A1s, less than 0.005% of N, less than 0.003% of O and the balance of iron and inevitable impurities. The production method comprises the procedures of molten iron pretreatment, converter smelting, LF refining, RH refining, slab continuous casting, heating, rolling, laminar cooling and coiling. Under the condition that expensive Mo element is not added, through reasonable component design and a controlled rolling and controlled cooling process, the yield strength of the wheel steel is larger than or equal to 500 MPa, the tensile strength is larger than or equal to 680 MPa, the ductility is larger than 18%, and the wheel steel has good welding performance and machining performance.
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