Production method of low-cost Q345q series bridge steel plate

A production method and low-cost technology, which can be used in the improvement of process efficiency, furnaces, heat treatment equipment, etc., and can solve the problems of complex process and high production cost

Pending Publication Date: 2022-05-27
XINJIANG BAYI IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to meet the above requirements, the traditional composition design of domestically produced Q345q series (Q345qC/D/E) steel plates mostly adopts the addition of microalloying elements such as Nb, V, Ti, Ni, etc., and the process is complicated and the production cost is high, so the alloy cost of this type of steel is reduced , which is of great significance to improve the economic benefits of enterprises
[0003] Chinese patent application publication number CN101880824B

Method used

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  • Production method of low-cost Q345q series bridge steel plate
  • Production method of low-cost Q345q series bridge steel plate
  • Production method of low-cost Q345q series bridge steel plate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The raw molten iron was subjected to deep desulfurization of molten iron, top-bottom blowing in converter, argon blowing in ladle, LF refining, RH vacuum treatment and continuous casting process to obtain the chemical composition in Table 1. The slab thickness was 250mm, and the slab soaking section temperature was 1222°C. The heating time is 252min, the soaking time is 49min, the first stage rolling temperature is 1090℃, the second stage rolling temperature is 930℃, the thickness of the intermediate billet is 50mm, the thickness of the rolled piece is 10mm, the final rolling temperature is 785℃, and the air cooling method is adopted after rolling. After cooling, the test results of the mechanical properties of the steel plates are obtained in Table 2.

[0025] Table 1 Chemical composition of 10mm Q345qE steel plate

[0026]

[0027] Table 2 Mechanical properties of 10mm Q345qE steel plate

[0028]

Embodiment 2

[0030]The implementation is the same as Example 1, the slab thickness is 250mm, the mass percentage of the slab chemical composition is shown in Table 3, the slab soaking section temperature is 1215°C, the heating time is 255min, the soaking time is 48min, the first stage rolling temperature is 1070°C, and the first stage rolling temperature is 1070°C. The starting rolling temperature of the second stage is 880℃, the thickness of the intermediate billet is 67mm, the thickness of the rolled piece is 16mm, and the final rolling temperature is 777℃. The temperature is 622°C. The test results of the mechanical properties of the obtained steel plates are shown in Table 3. The test results of the mechanical properties of the obtained steel plates are shown in Table 4.

[0031] Table 3 The chemical composition of the 16mm Q345qE steel plate

[0032]

Embodiment 3

[0034] The implementation is the same as Example 1, the slab thickness is 250mm, the mass percentage of the slab chemical composition is shown in Table 5, the slab soaking section temperature is 1235 ° C, the heating time is 257 min, the soaking time is 49 min, the first stage rolling temperature is 1095 ° C, and the first stage rolling temperature is 1095 ° C. The starting rolling temperature of the second stage is 880°C, the thickness of the intermediate billet is 91mm, the thickness of the rolled piece is 30mm, and the final rolling temperature is 786°C. After the rolling is completed, it is rapidly cooled by the ACC laminar cooling equipment. The temperature is 624°C. The test results of the mechanical properties of the obtained steel plates are shown in Table 6.

[0035] Table 5 The chemical composition of the 30mm Q345qE steel plate

[0036]

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Abstract

The invention discloses a production method of a low-cost Q345q series bridge steel plate. The steel plate comprises the following chemical components in percentage by mass: 0.10-0.13% of C; 1.4 to 1.5 percent of Mn; the steel plate comprises the following components in percentage by weight: 0.25 to 0.35 percent of Si, less than or equal to 0.004 percent of S, less than or equal to 0.015 percent of P, 0.020 to 0.040 percent of Als, 0.02 to 0.03 percent of Nb, 0.002 to 0.012 percent of Ti and less than or equal to 0.0005 percent of B. The thickness of the produced steel plate is 8 to 40mm; the adopted production method comprises the steps of molten iron pre-desulfurization treatment, 120 t converter treatment, LF refining and RH vacuum degassing, continuous casting, slab heating, controlled rolling, stack cooling, (flaw detection), finishing, sampling inspection, identification and warehousing. By adopting a low-temperature high-pressure technology and a TMCP controlled rolling and controlled cooling technology, the nucleation rate of ferrite is increased, so that ferrite grains are refined, and controlled cooling after controlled rolling can improve banded structures, refine pearlite pellets and reduce the interlayer spacing of pearlite, so that the effects of refined grain strengthening and precipitation strengthening are fully exerted, and the mechanical property index of a product is increased; and the alloy cost is greatly reduced while various properties of the bridge steel reach the national standard.

Description

technical field [0001] The invention relates to a production method of low-cost Q345q series bridge steel plates. Background technique [0002] Bridge slabs are widely used in railway bridges, highway bridges, large-scale river-crossing, sea-crossing bridges and urban light rail and other key projects. Bridges with a span greater than 300mm are all designed with steel structures, which are characterized by simple structure, light weight, high safety, capable of withstanding large static and dynamic loads, and long service time. Bridge steel is required to have high strength and toughness, welding performance, yield ratio, and resistance to lamellar tearing. In order to meet the above requirements, the traditional composition design of domestically produced Q345q series (Q345qC / D / E) steel plates mostly adopts the addition of micro-alloying elements such as Nb, V, Ti, Ni, etc. The process is complicated and the production cost is high, so the alloy cost of this type of steel ...

Claims

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Application Information

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IPC IPC(8): C21C7/064C21C7/10C21D8/02C21D9/00C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14
CPCC22C38/04C22C38/02C22C38/06C22C38/12C22C38/14C21C7/064C21C7/10C21D8/0205C21D8/0226C21D9/0081C21D2211/009C21D2211/005Y02P10/20
Inventor 陈晓山秦军赵虎
Owner XINJIANG BAYI IRON & STEEL
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