A niobium-molybdenum composite microalloyed high-strength bainite steel and its preparation method

A micro-alloying, bainitic steel technology, applied in the field of bainitic steel, can solve the problems of unfavorable industrial production, insufficient tensile strength, difficult plasticity and toughness, etc., achieve good strength and plasticity, and improve strength and toughness. , good matching of strength and plasticity

Inactive Publication Date: 2016-06-29
WUHAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The obtained steel types are either slightly insufficient in tensile strength, or the plasticity and toughness are difficult to match with the strength, and the preparation process is often complicated, and the production cycle is too long, which is extremely unfavorable for large-scale industrial production

Method used

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  • A niobium-molybdenum composite microalloyed high-strength bainite steel and its preparation method
  • A niobium-molybdenum composite microalloyed high-strength bainite steel and its preparation method
  • A niobium-molybdenum composite microalloyed high-strength bainite steel and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A niobium-molybdenum composite microalloyed high-strength bainite steel and a preparation method thereof. The preparation method of this embodiment is as follows: the billet is rolled by a hot rolling mill, the starting temperature of the rough rolling is 1150~1160°C, the starting temperature of the finishing rolling is 950~960°C, and the finishing rolling temperature is 900~910°C. ℃; then cool at a rate of 30~50℃ / s to 420~450℃, then air cool to 330~340℃, keep warm at 330~340℃ for 30~45min, and then water cool to room temperature.

[0025] The chemical composition and content of the slab are: C is 0.19~0.21wt%, Si is 1.43~1.47wt%, Mn is 1.94~1.98wt%, Nb is 0.025~0.026wt%, Mo is 0.142~0.148wt% %, P<0.008wt%, S<0.002wt%, N<0.004wt%, the rest is Fe and unavoidable impurities.

[0026] The tensile strength of the niobium-molybdenum composite microalloyed high-strength bainite steel prepared in this example is 1200-1250 MPa, and the elongation is 20.0-22.7%.

Embodiment 2

[0028] A niobium-molybdenum composite microalloyed high-strength bainite steel and a preparation method thereof. The preparation method of this embodiment is: rolling the cast slab by a hot rolling mill, the starting temperature of the rough rolling is 1160~1170°C, the starting temperature of the finishing rolling is 960~970°C, and the finishing rolling temperature is 910~920°C. ℃; then cool at a rate of 30~50℃ / s to 420~450℃, then air cool to 340~350℃, keep warm at 340~350℃ for 30~45min, and then water cool to room temperature.

[0029]The chemical composition and content of the billet are: C is 0.20~0.22wt%, Si is 1.46~1.49wt%, Mn is 1.97~2.01wt%, Nb is 0.025~0.026wt%, Mo is 0.147~0.149wt% %, P<0.008wt%, S<0.002wt%, N<0.004wt%, the rest is Fe and unavoidable impurities.

[0030] The tensile strength of the niobium-molybdenum composite microalloyed high-strength bainite steel prepared in this example is 1180-1230 MPa, and the elongation is 21.6-23.5%.

Embodiment 3

[0032] A niobium-molybdenum composite microalloyed high-strength bainite steel and a preparation method thereof. The preparation method of this embodiment is as follows: rolling the slab with a hot rolling mill, the starting temperature of the rough rolling is 1170~1180°C, the starting temperature of the finish rolling is 970~980°C, and the finish rolling temperature is 920~930°C. ℃; then cool at a rate of 30~50℃ / s to 420~450℃, then air cool to 350~360℃, keep warm at 350~360℃ for 30~45min, and then water cool to room temperature.

[0033] The chemical composition and content of the billet are: C is 0.21~0.224wt%, Si is 1.48~1.50wt%, Mn is 1.99~2.05wt%, Nb is 0.026~0.027wt%, Mo is 0.148~0.15wt% %, P<0.008wt%, S<0.002wt%, N<0.004wt%, the rest is Fe and unavoidable impurities.

[0034] The tensile strength of the niobium-molybdenum composite microalloyed high-strength bainite steel prepared in this example is 1160-1210 MPa, and the elongation is 22.3-23.0%.

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Abstract

The invention relates to a niobium-molybdenum composite micro-alloyed high-strength bainite steel and a preparation method thereof. The technical solution is: rolling the slab with a hot rolling mill, the starting temperature of the rough rolling is 1150-1200°C, the starting temperature of the finishing rolling is 950-1000°C, and the finishing rolling temperature is 900-950°C; and then Cool at a speed of 30~50°C / s to 420~450°C, then air cool to 330~380°C, keep warm at 330~380°C for 30~45min, and then water cool to room temperature. The chemical composition and content of the billet are: C is 0.19~0.224wt%, Si is 1.43~1.50wt%, Mn is 1.94~2.05wt%, Nb is 0.025~0.027wt%, Mo is 0.142~0.15wt% %, P<0.008wt%, S<0.002wt%, N<0.004wt%, the rest is Fe and unavoidable impurities. The invention has the characteristics of low cost, simple process and production cycle, and the strength and shape of the prepared product are well matched, and the comprehensive performance is excellent.

Description

technical field [0001] The invention belongs to the technical field of bainite steel. In particular, it relates to a niobium-molybdenum composite micro-alloyed high-strength bainite steel and a preparation method thereof. technical background [0002] Bainitic steel is a kind of steel with high strength and good toughness, which has always been the focus of research in the field of iron and steel materials. In the 1930s, Devenport and Bain discovered and studied the bainite structure. In the 1950s, Irvine and Pickering developed the Mo-B bainite steel that can obtain the bainite structure in the normalizing state. After decades of research and development, not only low-alloy bainitic steel with low cost and simple process has been developed at home and abroad, but also high-performance low-carbon bainitic steel has been developed, and it has been successfully used in the production of strip steel. Production. The invention and production of these steel grades have improve...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/12C21D8/02
Inventor 徐光张益杨海林薛正良徐耀文袁清
Owner WUHAN UNIV OF SCI & TECH
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