High strength low alloy hot rolling ferrite bainite weathering resistant steel and production method thereof

Abstract

The invention relates to a high strength low alloy hot rolling ferrite bainite weathering resistant steel and a production method thereof. The steel comprises the components by weight percent: 0.05-0.10% of C, 0.30-0.45% of Si, 1.00-1.50% of Mn, less than or equal to 0.015% of P, less than or equal to 0.01% of S, 0.50-0.70% of Cr, 0.20-0.30% of Ni, 0.20-0.40% of Cu, less than or equal to 0.05% ofAl, 0.01-0.025% of Ti, 0.03-0.05% of Nb and the rest of Fe and impurities; and the yield strength is more than or equal to 450MPa, and the welding cold crack susceptibility coefficient is less than orequal to 0.2. The invention has the advantages of low cost, high strength, low yield ratio, high weatherability, excellent weldability and low temperature toughness, simple process flow of the preparation technique and easy operation. Therefore, the invention can be widely applied to the fields such as bridges, buildings, containers, railway coaches, etc.

Description

technical field [0001] The invention relates to a high-strength low-alloy hot-rolled ferritic bainite weathering steel in the field of low-alloy steel manufacturing and a production method thereof, which can be applied to equipment such as containers and railway carriages. Background technique [0002] At present, about 1 / 6 of the annual output of steel in the world is consumed due to atmospheric corrosion, especially in my country, the direct economic loss suffered by this is more than 10 billion yuan per year. In order to solve this problem, people have developed methods such as grinding and coating steel, but the cost of taking such measures often accounts for a considerable proportion of the total project investment cost, resulting in a large amount of manpower, financial and material resources. After long-term research by people in the industry, people have found that by adjusting the composition and preparation process of steel materials, corrosion-resistant stainless ...

AI Technical Summary

Problems solved by technology

However, the content of alloying element Mn reaches 2.10-3.0%, resulting in too high carbon equivalent, which is not conducive to the welding performance of steel

[0008] The invention patent with the patent number US6315946 proposes an ultra-low carbon bainitic weathering steel with a carbon content of 0.015-0.035%. Boron is added to ensure its strength and hardenability, and to promote bainite transformation, so that the weldability and low-temperature toughness will be reduced if the alloy content is too high. After the thermomechanical control rolling process in the production process, it will be directly accelerated cooling, without Make full use of the precipitation strengthening and microstructure refinement of niobium etc.

[0009] The invention patent with the patent number US 6056833 proposes a high-strength low-yield ratio weathering steel with thermomechanical control, the yield strength is greater than 490MPa, and the yield ratio is less than 0.85. Excessive content (0.06%-0.14%) increases the cost of steel and reduces the weldability and low temperature toughness of steel

[0010] However, looking at the technologies disclosed in the above patents, there are certain deficiencies in them, and they cannot fully meet the service requirements of containers and railway vehicles in my country and the actual needs of production equipment conditions.

Images