A kind of low yield ratio high plastic ultrafine grain high strength steel and its manufacturing method

Abstract

The invention discloses a high-strength steel with low yield ratio, high plasticity and ultra-fine grain and a manufacturing method. The chemical composition weight percentage of steel is: C: 0.06~0.09%, Si: 0.15~0.25%, Mn: 1.20~1.50%, P: ≤0.015%, S: ≤0.005%, Nb: 0.020~0.040%, V: 0.010~0.030%, Ti: 0.008~0.015%, Cr: 0.10~0.30%, Ni: 0.10~0.30%, Cu: 0.10~0.30%, Al: 0.010~0.050%, and the balance is Fe and unavoidable impurities. The invention obtains the bainite structure by adopting the controlled rolling and controlled cooling process. Through the heat treatment process, an ultra-fine grain structure with bimodal distribution is obtained, which makes the material have characteristics such as low yield ratio, superplasticity, and high strength. The production process is stable, the operability is strong, the cost is low, and the comprehensive performance of the obtained material is excellent.

Description

technical field

[0001] The invention relates to a high-strength steel, in particular to a high-strength steel with low yield ratio, high plasticity, ultra-fine grain and a manufacturing method thereof. Background technique

[0002] In the 21st century, steel is still the dominant structural material, and no material can completely replace steel. With the development of society and economy, the iron and steel industry is facing three major pressures: saving resources, saving energy, and protecting the environment. Therefore, improving steel quality, reducing costs, developing human-friendly steel materials, and greatly improving their comprehensive mechanical properties have become the main directions of steel material research. Among them, the low-cost production of fine-grained high-strength steel using thermomechanical controlled rolling technology (TMCP) and deformation-induced ferrite transformation technology (DIFT) is the development direction of the current metallurg...

Examples

Embodiment Construction

[0020] A low yield ratio high plastic ultrafine grain high strength steel, according to the production process of the present invention, the actual chemical composition of the steel of the present invention is smelted and rolled as shown in Table 1.

[0021] A method for manufacturing ultra-fine-grained high-strength steel with low yield ratio and high plasticity, the specific requirements of the manufacturing method are as follows:

[0022] Rolling process: controlled rolling and controlled cooling process is adopted, the heating temperature of the continuous casting slab before rolling is 1180 ℃ ~ 1200 ℃; two-stage controlled rolling is adopted in the austenite recrystallization zone and austenite non-recrystallization zone, and each pass of rough rolling The secondary reduction rate is 10-15%, the rough rolling final rolling temperature is 1000-1050℃, and the rough rolling is 1.6-2.0 times the thickness of the finished product. The intermediate billet is 1.6-2.0 times the th...

technical field

[0001] The invention relates to a high-strength steel, in particular to a high-strength steel with low yield ratio, high plasticity, ultra-fine grain and a manufacturing method thereof. Background technique

[0002] In the 21st century, steel is still the dominant structural material, and no material can completely replace steel. With the development of society and economy, the iron and steel industry is facing three major pressures: saving resources, saving energy, and protecting the environment. Therefore, improving steel quality, reducing costs, developing human-friendly steel materials, and greatly improving their comprehensive mechanical properties have become the main directions of steel material research. Among them, the low-cost production of fine-grained high-strength steel using thermomechanical controlled rolling technology (TMCP) and deformation-induced ferrite transformation technology (DIFT) is the development direction of the current metallurg...

Examples

Embodiment Construction

[0020] A low yield ratio high plastic ultrafine grain high strength steel, according to the production process of the present invention, the actual chemical composition of the steel of the present invention is smelted and rolled as shown in Table 1.

[0021] A method for manufacturing ultra-fine-grained high-strength steel with low yield ratio and high plasticity, the specific requirements of the manufacturing method are as follows:

[0022] Rolling process: controlled rolling and controlled cooling process is adopted, the heating temperature of the continuous casting slab before rolling is 1180 ℃ ~ 1200 ℃; two-stage controlled rolling is adopted in the austenite recrystallization zone and austenite non-recrystallization zone, and each pass of rough rolling The secondary reduction rate is 10-15%, the rough rolling final rolling temperature is 1000-1050℃, and the rough rolling is 1.6-2.0 times the thickness of the finished product. The intermediate billet is 1.6-2.0 times the th...

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