Vanadium-nitrogen-chromium microalloyed Q550 hot-rolled strip steel and preparation method thereof

A hot-rolled strip and micro-alloying technology, applied in the field of hot-rolled strip manufacturing, can solve the problems of large amount of alloy and large fluctuation of structure and properties, and achieve the advantages of short process flow, high uniformity of structure and properties, and low alloy cost. Effect

Active Publication Date: 2018-06-22
NORTHEASTERN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to provide a V-N-Cr micro-alloyed hot-rolled strip and its preparation method in view of the fact that the Q550 hot-rolled strip uses a large amount of expensive alloys and has large fluctuations in microstructure and properties in the prior art.

Method used

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  • Vanadium-nitrogen-chromium microalloyed Q550 hot-rolled strip steel and preparation method thereof
  • Vanadium-nitrogen-chromium microalloyed Q550 hot-rolled strip steel and preparation method thereof
  • Vanadium-nitrogen-chromium microalloyed Q550 hot-rolled strip steel and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0032] To prepare a V-N-Cr microalloyed hot-rolled strip with a thickness of 20.0mm, the process steps are as follows:

[0033]The alloy billet with a thickness of 140mm is heated to 1200 ℃ with the furnace and kept for 4 hours. Its chemical composition is: C: 0.05%, Mn: 2.0%, Si: 0.50%, S: 0.002%, P: 0.010%, Al : 0.05%, V: 0.15%, N: 0.020%, Cr: 0.30%, the balance is Fe and other inevitable impurities; then it is hot rolled into a 20.0mm thick hot rolled sheet after 11 passes. The starting and finishing temperatures in the rough rolling stage were 1160°C and 1100°C, respectively, with 5 passes of rough rolling to 56 mm, and a pass reduction rate of 14-18%; the starting and finishing temperatures of the finishing rolling stage were respectively At 955°C and 890°C, finish rolling to 20.0mm in 6 passes, and the pass reduction rate is 14-17%. After the hot rolling is completed, the cooling rate is 15°C / s and water-cooled to 585°C, such as figure 1 shown;

[0034] The hot-rolled...

Embodiment 2

[0036] To prepare a V-N-Cr microalloyed hot-rolled strip with a thickness of 10.0mm, the process steps are as follows:

[0037] The alloy billet with a thickness of 80mm is heated to 1150 ℃ with the furnace and kept for 3 hours. Its chemical composition by weight percentage is: C: 0.11%, Mn: 1.8%, Si: 0.30%, S: 0.003%, P: 0.005%, Al : 0.01%, V: 0.10%, N: 0.013%, Cr: 0.20%, the balance is Fe and other inevitable impurities; then it is hot rolled into a 10.0mm thick hot rolled sheet after 9 passes. The starting and finishing temperatures of the rough rolling stage were 1100°C and 1060°C, respectively, and the rough rolling was carried out to 40 mm in 3 passes, and the reduction rate of each pass was 19-23%; the starting and finishing temperatures of the finishing rolling stage were respectively At 915°C and 850°C, finish rolling to 10.0mm in 6 passes, and the pass reduction rate is 18-23%. After the hot rolling is completed, the cooling rate is 32°C / s and the water is cooled to...

Embodiment 3

[0040] To prepare a V-N-Cr microalloyed hot-rolled strip with a thickness of 2.5mm, the process steps are as follows:

[0041] The alloy billet with a thickness of 50mm was heated to 1100°C with the furnace and kept for 2h. Its chemical composition by weight percentage was: C: 0.15%, Mn: 1.5%, Si: 0.10%, S: 0.005%, P: 0.015%, Al : 0.04%, V: 0.06%, N: 0.008%, Cr: 0.10%, the balance is Fe and other inevitable impurities; then it is hot rolled into a 2.5mm thick hot rolled sheet after 9 passes. The starting and finishing temperatures in the rough rolling stage are 1060°C and 980°C, respectively, with 3 passes of rough rolling to 18 mm, and the pass reduction rate of 28 to 30%; the starting and finishing temperatures of the finishing rolling stage are respectively At 870°C and 805°C, finish rolling to 2.5mm in 6 passes, and the pass reduction rate is 28-30%. After the hot rolling is completed, the cooling rate is 45°C / s and water-cooled to 520°C, such as figure 1 shown.

[0042...

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Abstract

The invention belongs to the field of manufacturing of hot-rolled strip steel, and particularly relates to vanadium-nitrogen-chromium microalloyed Q550 hot-rolled strip steel and a preparation methodthereof. The vanadium-nitrogen-chromium microalloyed Q550 hot-rolled strip steel comprises, by weight percentage, 0.05-0.15% of carbon, 1.5-2.0% of manganese, 0.10-0.50% of silicon, 0.002-0.005% of sulfur, 0.005-0.015% of phosphorus, 0.01-0.05% of aluminum, 0.06-0.15% of vanadium, 0.008-0.020% of nitrogen, 0.10-0.30% of chromium, and the balance ferrum and other inevitable impurities. The metallographic structure of the hot-rolled strip steel is polygonal ferrites, needle-shaped ferrites and granular bainites. The preparation method has the advantages that the operation process is simple, theproduction cost is low, the product performance is stable, and industrial production can be realized easily.

Description

technical field [0001] The invention belongs to the field of hot-rolled strip steel manufacturing, and in particular relates to a V-N-Cr microalloyed Q550 grade hot-rolled strip steel and a preparation method thereof. Background technique [0002] Hot-rolled strip steel is a type of steel with a relatively high production capacity, and its use is extremely extensive. The output of hot-rolled strip steel in developed countries even accounts for more than 50% of hot-rolled steel. It is mainly used in construction machinery manufacturing industry, automobile structure, construction engineering, petroleum Pipelines, daily hardware and many other fields, among which Q550 low-alloy high-strength steel is mainly used as welded structural parts such as coal machine brackets, automobile wheel beams, low-temperature pipelines, etc., which require excellent comprehensive mechanical properties such as strength, plasticity and toughness. Both have good welding performance. [0003] In i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/38C22C38/24C22C38/02C22C38/06B21C37/02C21D8/02
CPCB21C37/02C21D8/0205C21D8/0221C21D8/0247C22C38/001C22C38/02C22C38/06C22C38/24C22C38/38
Inventor 胡军张彬刘悦张世超高彩茹高秀华杜林秀
Owner NORTHEASTERN UNIV
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