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Production method of tempering type low-yield-ratio bridge steel

A production method and low yield ratio technology, which is applied in the production field of tempered low yield ratio bridge steel, to achieve the effect of low alloy cost and reduced energy consumption of steel burning

Active Publication Date: 2021-07-30
HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The present invention aims to provide a production method of tempered low-yield-ratio bridge steel to solve the production technical problems in the process of existing low-yield-ratio bridge steel

Method used

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  • Production method of tempering type low-yield-ratio bridge steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Embodiment 1: The production method of 6mm low yield strength ratio Q420qE steel plate.

[0021] Chemical composition of steel: C=0.08%, Si=0.24%, Mn=1.56%, P=0.010%, S=0.001%, Alt=0.030%, Nb=0.015%, Ti=0.015%, Cr=0.18% , Mo=0.10%, Cu=0.17%, Pcm=0.19%, the balance is Fe and unavoidable impurities.

[0022] The production process steps and parameters of steel are:

[0023] (1) Heating: The billet is directly loaded, the furnace charging temperature: 516°C, the furnace temperature: 1140~1190°C, and the total time in the furnace: 140min.

[0024] (2) Rough rolling: the intermediate billet is set at 55mm, the starting rolling temperature is 1150°C, the final rolling temperature is 990°C, 7 passes, and the cumulative reduction rate is 69.5%.

[0025] (3) Finish rolling: the starting rolling temperature is 915°C, the final rolling temperature is 805~825°C, 7 passes, and the cumulative reduction rate is 89.1%.

[0026] (4) Cooling: The starting cooling temperature is 810~82...

Embodiment 2

[0029] Embodiment 2: The production method of 20mm low yield strength ratio Q420qE steel plate.

[0030] Chemical composition of steel: C=0.07%, Si=0.26%, Mn=1.54%, P=0.010%, S=0.001%, Alt=0.032%, Nb=0.018%, Ti=0.016%, Cr=0.17% , Mo=0.11%, Cu=0.18%, Pcm=0.18%, the balance is Fe and unavoidable impurities.

[0031] The production process steps and parameters of steel are:

[0032] (1) Heating: The billet is directly charged, the furnace charging temperature is 532°C, the furnace temperature is 1160~1188°C, and the total time in the furnace is 162min.

[0033] (2) Rough rolling: the intermediate billet is set at 80mm, the rolling start temperature is 1172°C, the final rolling temperature is 992°C, 7 passes, and the cumulative reduction rate is 69.2%.

[0034] (3) Finish rolling: the starting rolling temperature is 880°C, the final rolling temperature is 801~822°C, 7 passes, and the cumulative reduction rate is 75%.

[0035] (4) Cooling: The starting cooling temperature is 796...

Embodiment 3

[0038] Embodiment 3: The production method of 50mm low yield strength ratio Q420qE steel plate.

[0039] Chemical composition of steel: C=0.08%, Si=0.29%, Mn=1.56%, P=0.010%, S=0.001%, Alt=0.040%, Nb=0.022%, Ti=0.015%, Cr=0.18% , Mo=0.10%, Cu=0.19%, Pcm=0.19%, the balance is Fe and unavoidable impurities.

[0040] The production process steps and parameters of steel are:

[0041] (1) Heating: The billet is directly charged, the furnace charging temperature is 572°C, the furnace temperature is 1172~1188°C, and the total time in the furnace is 176min.

[0042] (2) Rough rolling: the intermediate billet is set at 125mm, the starting rolling temperature is 1176°C, the final rolling temperature is 995°C, 5 passes, and the cumulative reduction rate is 51.9%.

[0043] (3) Finish rolling: start rolling temperature 840°C, finish rolling temperature 790~800°C, 9 passes, cumulative reduction rate 60%.

[0044] (4) Cooling: The starting cooling temperature is 775~798°C, the cooling rat...

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Abstract

The invention relates to a production method of tempering type low-yield-ratio bridge steel. The process route comprises molten iron pretreatment, converter treatment, refining, continuous casting, heating, rolling, cooling and tempering, and the steel is prepared from the following chemical components: 0.07%-0.09% of C, 0.20%-0.30% of Si, 1.52%-1.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.003% of S, 0.020%-0.045% of Alt, 0.01%-0.030% of Nb, 0.012%-0.020% of Ti, 0.16%-0.20% of Cr, 0.08%-0.12% of Mo, 0.16%-0.20% of Cu, less than or equal to 0.22% of Pcm and the balance of Fe and inevitable impurities. The steel produced through the method has the advantages of being low in cost, narrow in component and the like, the produced steel plate with the thickness of 6-50 mm is larger than or equal to 420 MPa in yield strength, smaller than or equal to 0.80 in yield ratio and larger than or equal to 200 J in impact toughness at the temperature of -40 DEG C, and the steel plate is low in manufacturing cost, low in yield ratio, high in strength and high in low-temperature toughness.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a production method of tempered low yield ratio bridge steel. Background technique [0002] With the rapid development of economic construction and the start of construction of bridges with large spans, complex structures, and large flows, the demand for high-performance steel for bridge structures is increasing. From the aspects of lightweight design, safety and reliability, low maintenance cost and service life, high strength, strong low temperature toughness, corrosion resistance and low yield ratio have become the main development direction of modern bridge structural steel, research and development of higher strength grades High-performance bridge steel is of great significance to promote the development of bridge construction. [0003] U.S. Patent US6056833 discloses a thermomechanically rolled high-strength low-yield-ratio atmospheric corrosion-resistant steel. Mo=0.08~...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/06C22C38/38C22C38/26C22C38/28C22C38/22C22C38/20C21D8/02
CPCC22C38/02C22C38/06C22C38/38C22C38/26C22C38/28C22C38/22C22C38/20C21D8/0226C21D8/0263
Inventor 李中平李建宇何航熊祥江张勇伟史术华范明陈奇明
Owner HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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