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Q345B medium-wide band steel and production method thereof

A production method and wide-band steel technology, applied to Q345B wide-band steel and its production field, can solve problems such as anisotropy, severe band structure, and reduced toughness, and achieve the goals of reducing the amount of addition, improving the internal structure, and improving product quality Effect

Inactive Publication Date: 2015-01-28
HEBEI IRON AND STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above-mentioned patent application mainly uses the fine-grain strengthening and precipitation strengthening effects of niobium and titanium to produce Q345B steel coils. The content of manganese is still high, and there are also the above-mentioned problems such as serious banded structure, reduced toughness and anisotropy.

Method used

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  • Q345B medium-wide band steel and production method thereof
  • Q345B medium-wide band steel and production method thereof
  • Q345B medium-wide band steel and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Embodiment 1: The technological process of the production method of wide-band steel in this Q345B is: steel billet→reheating furnace heating→high-pressure water descaling→rough rolling→hot coil box→finish rolling unit rolling→layer cooling→coiling; the specific process Conditions are described below.

[0021] Put the billet shown in Example 1 in Table 1 into a heating furnace with a furnace temperature of 1200±10°C in the soaking section and heat it for 150 minutes. The rolling temperature is 900°C, the total reduction rate of hot rolling is 92%, the laminar cooling speed range is 20°C / s, and the coiling temperature after layer cooling is 680°C. The test results of the mechanical properties of the medium and wide band steel coils obtained in this example are shown in Table 2 below.

[0022] Table 2: Mechanical properties of the medium and wide band steel coils obtained in Example 1

[0023]

Embodiment 2

[0024] Embodiment 2: The production method of the wide-band steel in this Q345B adopts the following specific processes.

[0025] Put the billet shown in Example 2 in Table 1 into a heating furnace with a furnace temperature of 1200±10°C in the soaking section and heat it for 140 minutes. The rolling temperature is 890°C, the total hot rolling reduction rate is 96%, the laminar cooling speed range is 18°C / s, and the coiling temperature after layer cooling is 660°C. The test results of the mechanical properties of the medium and wide band steel coils obtained in this example are shown in Table 3 below.

[0026] Table 3: The mechanical properties of the wide-band steel coil obtained in embodiment 2

[0027]

Embodiment 3

[0028] Embodiment 3: The production method of the wide-band steel in this Q345B adopts the following specific processes.

[0029] Put the billet shown in Example 3 in Table 1 into a heating furnace with a furnace temperature of 1190±10°C in the soaking section and heat it for 140 minutes. After being released from the furnace, the billet is descaled by high-pressure water and rolled. The rolling temperature is 870°C, the total reduction rate of hot rolling is 91%, the laminar cooling speed range is 25°C / s, and the coiling temperature after layer cooling is 660°C. The test results of the mechanical properties of the medium and wide band steel coil obtained in this embodiment are shown in Table 4 below.

[0030] Table 4: Mechanical properties of the medium and wide band steel coils obtained in Example 3

[0031]

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PUM

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Abstract

The invention discloses Q345B medium-wide band steel and a production method thereof. The production method comprises the steps of heating, hot rolling, cooling and winding. A steel billet contains the following ingredients by weight percent: 0.14 to 0.19 percent of C, less than or equal to 0.25 percent of Si, 0.45 to 0.85 percent of Mn, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, 0.010 to 0.040 percent of V, 0.004 to 0.015 percent of N, and the balance of Fe and unavoidable impurities. The medium-wide band steel adopts nitrided ferrovanadium to be under microalloying, and the precipitation of vanadium is promoted by increasing the nitrogen, and the crystal grain is refined; trace amount of vanadium is used for substituting a great amount of manganese, and the precipitation strengthening is used for substituting the solution strengthening. The content of Mn in the medium-wide band steel is reduced by about 0.45 percent; meanwhile, by adding V, the cost of the steel per tonnage is effectively reduced; the precipitation strengthening and the fine-grain strengthening are adopted as main strengthening means, so that the content of sulfide impurities is reduced, the internal tissue is improved, and effects for reducing the production cost and improving the quality of the medium-wide band steel product can be achieved. By adopting the method, the addition amount of the alloy element is reduced, the reduction production is realized, the fine-grain strengthening and precipitation strengthening can be better realized, and the comprehensive performance of the product is better.

Description

technical field [0001] The invention relates to a hot-rolled medium wide-band steel and a production method thereof, in particular to a Q345B medium wide-band steel and a production method thereof. Background technique [0002] Low-alloy high-strength Q345B steel strip is a low-carbon steel with a C content of less than 0.20%. Due to its good comprehensive performance, it is widely used in construction machinery, building structures, petrochemicals, etc., and plays a pivotal role in the development of the national economy. However, in the production process, the product is prone to unqualified cold bending, abnormal structure, bainite, banded structure and other phenomena, which affect the mechanical properties and use requirements of the product. Conventional Q345B steel usually adds 1.0% to 1.7% Mn element in the steel to ensure the strength of the product. Manganese mainly plays a solid solution strengthening role in the steel. Recent studies have shown that when W(Mn)<...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/12C21D8/02
CPCC22C38/12C21D8/0226C22C38/001C22C38/04
Inventor 王全利杜建良蒋建军范文斌尹志尧高玲玲
Owner HEBEI IRON AND STEEL
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