Hot rolled weatherproof bridge steel with yield strength of 500 MPa level and manufacturing method thereof

A yield strength, bridge steel technology, applied in the field of metal materials, can solve the problems of strength and weather resistance that need to be improved

Inactive Publication Date: 2010-11-24
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This steel adopts non-tempered quality controlled rolling and controlled cooling process, which has good low temperature toughness and weldability, but the strength and weather resistance still need to be improved

Method used

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  • Hot rolled weatherproof bridge steel with yield strength of 500 MPa level and manufacturing method thereof
  • Hot rolled weatherproof bridge steel with yield strength of 500 MPa level and manufacturing method thereof
  • Hot rolled weatherproof bridge steel with yield strength of 500 MPa level and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Example 1 The chemical components contained in the hot-rolled weathering bridge steel with a yield strength of 500 MPa in this example are as follows: C 0.05%, Si 0.38%, Mn 1.46%, P 0.013%, S 0.0020%, Cu 0.36 %, Ni 0.33%, Cr 0.5%, Mo 0.15%, Nb 0.056%, Ti 0.021%, Al 0.023%, and the rest are Fe and unavoidable impurities.

[0036] The preparation process of the weather-resistant bridge steel in this example is as follows: the smelting raw materials are configured according to the chemical composition of the weather-resistant bridge steel, and the smelting raw materials are smelted, molten iron pre-desulfurization, converter top-bottom composite blowing, RH vacuum cycle degassing, and rare earth or Ca treatment Finally, through the whole process of protective pouring, the target billet is formed. .

[0037] After the slab is heated at 1250°C for 2 hours, two-stage rolling is carried out, in which the rough rolling start temperature is 1080°C, the cumulative rough rolling ...

Embodiment 2

[0038]Example 2 In this example, the chemical components contained in the hot-rolled weathering bridge steel with a yield strength of 500 MPa are as follows: C 0.07%, Si 0.39%, Mn 1.22%, P 0.008%, S 0.0044%, Cu 0.4%, Ni 0.3%, Cr 0.5%, Mo 0.15%, Nb 0.05%, Ti 0.02%, Al 0.03%, and the rest are Fe and unavoidable impurities.

[0039] The preparation process of the weather-resistant bridge steel in this example is as follows: the slab is made according to the same process as in Example 1, and then the slab is heated at 1250°C for 2 hours, and then two-stage rolling is carried out, wherein the rough rolling start temperature is 1100°C, the cumulative downdraft of rough rolling is 60%, the temperature of finish rolling is 940°C, the end temperature of finish rolling is 840°C, and the cumulative downdraft of finish rolling is 75%. After rolling, the rolled piece is cooled to 530°C, the cooling rate is 11°C / s, and the mechanical properties of the finished weather-resistant bridge steel...

Embodiment 1～2

[0040] Table 1 Examples 1-2 mechanical properties

[0041]

[0042] The bridge weathering steel described in Example 1-2 of the present invention and the comparison steel 1-1 and comparison steel 1-2 proposed in the invention patent with the publication number CN1609257A and the comparison steel 2 proposed in the invention patent with the patent number US6315946 The comparison of mechanical properties and corrosion resistance is shown in Table 1. The calculation formula of the corrosion resistance index I in the table is the Legault-Leckie formula revised in the American Society for Testing and Materials standard ASTM G101-01. The higher the value, the stronger the corrosion resistance. It can be seen from the above table that compared with the comparison steel, the steel of the present invention has high strength, better impact energy at low temperature, and better corrosion resistance.

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Abstract

The invention relates to a hot rolled weatherproof bridge steel with yield strength of 500 MPa level and a preparation process thereof. The weatherproof bridge steel comprises the following chemical components in percentage by weight: 0.03-0.08% of C, no more than 0.5% of Si, 1.0-1.5% of Mn, no more than 0.015% of P, no more than 0.01% of S, 0.3-0.6% of Cu, 0.20-0.50% of Ni, 0.40-1.0% of Cr, 0.15-0.35% of Mo, 0.03-0.08% of Nb, no more than 0.04% of Ti, no more than 0.04% of Als and balance Fe and impurities, and the weatherproof bridge steel is mainly prepared by a control rolling and cooling process. The weatherproof bridge steel has the advantages of simple composition, low cost, yield strength more than 500 MPa, favorable low-temperature tenacity, weldability and weatherability, convenient preparation process and high controllability. The preparation method can be widely used in the production field of various bridge steels.

Description

technical field [0001] The invention specifically relates to a hot-rolled high-strength bridge steel in the field of metal materials and a manufacturing method thereof. The minimum yield strength of the hot-rolled high-strength bridge steel is 500 MPa, and the impact energy is greater than 47J at a low temperature of -40°C. Excellent atmospheric corrosion resistance. Background technique [0002] With the development of large steel structure bridges towards fully welded structures and high parameters, the requirements for the safety and reliability of bridge structures are becoming more and more stringent. This puts forward higher requirements for the quality of bridge steel plates, that is, not only has high strength to meet the requirements of lightweight structures, but also has excellent low-temperature toughness, weldability and corrosion resistance, etc., to meet the safety and reliability of steel structures. Longevity and other requirements. In this context, materi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/48C22C33/04C21D8/00
Inventor 李化龙陈爱华赵良峰刘俭
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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