A kind of v-n-cr microalloyed q550 grade hot-rolled strip steel and its preparation method

A hot-rolled strip steel and micro-alloying technology, which is applied in the field of hot-rolled strip steel manufacturing, can solve the problems of large amount of alloy and large fluctuations in structure and properties, and achieve short process flow, high uniformity of structure and properties, and simple operation process Effect

Active Publication Date: 2020-02-07
NORTHEASTERN UNIV LIAONING
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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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  • A kind of v-n-cr microalloyed q550 grade hot-rolled strip steel and its preparation method
  • A kind of v-n-cr microalloyed q550 grade hot-rolled strip steel and its preparation method
  • A kind of v-n-cr microalloyed q550 grade hot-rolled strip steel and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The V-N-Cr microalloy hot-rolled steel strip whose thickness is 20.0mm is prepared, and the process steps are as follows:

[0033]Heat the alloy billet with a thickness of 140mm to 1200°C with the furnace and keep it warm for 4 hours. Its chemical composition is as follows: 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 unavoidable impurities; followed by 11 passes of hot rolling into a 20.0mm thick hot rolled sheet. The starting and finishing temperatures of the rough rolling stage are 1160°C and 1100°C respectively, the rough rolling is carried out in 5 passes to 56mm, and the pass reduction rate is 14-18%; the starting and finishing temperatures of the finish rolling stage are respectively At 955°C and 890°C, finish rolling to 20.0mm in 6 passes, and the reduction rate of each pass is 14-17%. After hot rolling, water cooling to 585°C at a cooling rate of 15°C / s, such as figure 1 shown;

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Embodiment 2

[0036] The V-N-Cr microalloy hot-rolled steel strip whose thickness is 10.0mm is prepared, and the process steps are as follows:

[0037] Heat the alloy billet with a thickness of 80mm to 1150°C with the furnace and keep it warm for 3 hours. Its chemical composition 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 unavoidable impurities; followed by 9 passes of hot rolling into a 10.0mm thick hot rolled sheet. The starting and finishing temperatures of the rough rolling stage were 1100°C and 1060°C, respectively, and the rough rolling was carried out in 3 passes to 40mm, and the reduction rate of each pass was 19-23%. The starting and finishing temperatures of the finish rolling stage were respectively At 915°C and 850°C, finish rolling to 10.0mm in 6 passes, and the reduction rate of each pass is 18-23%. After hot rolling, water cooling to 566°C at a cooling rate of 32°C / s, such as figure 1 show...

Embodiment 3

[0040] The V-N-Cr microalloy hot-rolled steel strip whose thickness is 2.5mm is prepared, and the process steps are as follows:

[0041] Heat the alloy billet with a thickness of 50mm to 1100°C with the furnace and hold it for 2 hours. Its chemical composition is as follows: 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 unavoidable impurities; followed by 9 passes of hot rolling into a 2.5mm thick hot rolled sheet. The starting and finishing temperatures of the rough rolling stage were 1060°C and 980°C, respectively, and the rough rolling was carried out in 3 passes to 18mm, and the pass reduction rate was 28-30%. The starting and finishing temperatures of the finish rolling stage were respectively At 870°C and 805°C, finish rolling to 2.5mm in 6 passes, and the reduction rate of each pass is 28-30%. After hot rolling, water cooling to 520°C at a cooling rate of 45°C / s, such as figure 1 shown.

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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 steel strip manufacturing, and in particular relates to a V-N-Cr microalloyed Q550 grade hot-rolled steel strip and a preparation method thereof. Background technique [0002] Hot-rolled strip steel is a steel product with a relatively high production capacity. It has a wide range of uses. The output of hot-rolled strip steel in developed countries even accounts for more than 50% of hot-rolled steel products. It is mainly used in construction machinery manufacturing industries, automobile structures, construction projects, petroleum In many fields such as pipelines and daily hardware, Q550 low-alloy high-strength steel is mainly used as welded structural parts such as coal machine brackets, automobile wheel girders, and low-temperature pipelines. It is required to have excellent comprehensive mechanical properties such as strength, plasticity, and toughness. Both good welding performance. [0003] In in...

Claims

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Application Information

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