700MPa grade cold-resistant high-strength structural steel plate and manufacturing method thereof

A technology of structural steel plate and manufacturing method, which is applied in the field of smelting, can solve the problems of short service life and fatigue performance, insufficient toughness, low strength, etc., and achieve the effects of eliminating internal stress in the organization, improving the purity of molten steel, and increasing the plasticity and toughness index

Inactive Publication Date: 2015-09-23
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most of the Q345B grades used have low strength and insufficient toughness. The steel plate needs to be thickened, which makes the vehicle consume more fuel, is not environmentally friendly, cannot increase the vehicle capacity, and has a short service life and fatigue performance. It does not meet modern energy-saving and environmental protection requirements. major trend

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Slab smelting composition is:

[0029] C: 0.16%, Si: 0.29%, Mn: 1.40%, P: 0.015%, S: 0.002%, Al: 0.022%, Cu: 0.21%, B: 0.0016%; Mo: 0.12%; Avoid impurities.

[0030] (1) KR molten iron pretreatment, the sulfur content is controlled below 0.005%;

[0031] (2) BOF oxygen and argon top and bottom blowing and decarburization;

[0032] (3) LF refining outside the furnace: the heating time is 18 minutes, the white slag is desulfurized, and the titanium content is adjusted by adding a trace alloy; finally, the ferroboron alloy is added;

[0033] (4) VD / RH vacuum degassing: under vacuum 200Pa for 20 minutes, and argon soft blowing for 12 minutes after feeding the wire;

[0034] (5) Slab heating: the soaking temperature range is about 1120 °C, and the soaking time range is about 3.0 hours. By using finely dispersed TiN particles and low-temperature heating, the growth of austenite grains is suppressed, and fine and uniform austenite grains are obtained. body grain;

[0035]...

Embodiment 2

[0043] Slab smelting composition is:

[0044] C: 0.17%, Si: 0.26%, Mn: 1.46%, P: 0.015%, S: 0.001%, Al: 0.022%, Cu: 0.21%, B: 0.0015%; Mo: 0.16%; Avoid impurities.

[0045] (1) KR molten iron pretreatment, the sulfur content is controlled below 0.005%;

[0046] (2) BOF oxygen and argon top and bottom blowing decarburization;

[0047] (3) LF refining outside the furnace: the heating time is 15 minutes, the white slag is desulfurized, and the titanium content is adjusted by adding a trace alloy; finally, the ferroboron alloy is added;

[0048] (4) VD / RH vacuum degassing: under vacuum 200Pa for 20 minutes, and argon soft blowing for 10 minutes after feeding the wire;

[0049] (5) Slab heating: soaking temperature range 1100 ℃, soaking time range 2.5 hours. By using finely dispersed TiN particles and low-temperature heating to suppress the growth of austenite grains, fine and uniform austenite grains are obtained.

[0050](6) Rough rolling: the rolling temperature is 1050°C, ...

Embodiment 3

[0058] C: 0.18%, Si: 0.29%, Mn: 1.62%, P: 0.017%, S: 0.001%, Al: 0.020%, Cu: 0.14%, B: 0.0022%; Mo: 0.18%; Avoid impurities.

[0059] (1) KR molten iron pretreatment, the sulfur content is controlled below 0.005%;

[0060] (2) BOF oxygen and argon top and bottom blowing and decarburization;

[0061] (3) LF refining outside the furnace: the heating time is 20 minutes, the white slag is desulfurized, and the titanium content is adjusted by adding a trace alloy; finally, the ferroboron alloy is added;

[0062] (4) VD / RH vacuum degassing: under vacuum 200Pa for 20 minutes, and argon soft blowing for 15 minutes after feeding the wire;

[0063] (5) Slab heating: soaking temperature range is 1150℃, soaking time range is 4.0 hours. By using finely dispersed TiN particles and low-temperature heating to suppress the growth of austenite grains, fine and uniform austenite grains are obtained.

[0064] (6) Rough rolling: the rolling temperature is 1100℃, and the single-pass reduction r...

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Abstract

The invention belongs to the technical field of smelting, and in particular relates to a 700MPa grade cold-resistant high-strength structural steel plate and a manufacturing method thereof. The 700MPa grade cold-resistant high-strength structural steel plate is characterized by comprising the following main components: 0.12-0.22% of carbon, 0.10-0.55% of Si, 0.80-1.80% of manganese, no more than 0.55% of copper, no more than 0.020% of phosphor, no more than 0.005% of sulfur, 0.0005- 0.0030% of boron, 0.08-0.50% of molybdenum and the balance of Fe and unavoidable impurities. The high-strength steel produced by the invention for various 25-80 ton heavy-duty truck beam frame structure in rigid regions achieves excellent strength and toughness coupling, ductile-brittle transition temperature below -40 DEG C, and flatness of 0.9-2.5mm / m. The steel plate has yield strength of 610-750 MPa, and tensile strength in the range of 730-950 MPa; through reasonable quenching and tempering process, the steel plate gains strength of 700MPa, has tissue stress eliminated, and shows high impact toughness below -40 DEG C, improved plastic toughness index, and elongation reaching 16-26%. Therefore, compared with the Q345 prior art, the present invention makes obvious substantive progress and the enforcement effect is substantial.

Description

technical field [0001] The invention belongs to the technical field of smelting, and in particular relates to a 700MPa grade cold-resistant high-strength structural steel plate and a manufacturing method thereof. Background technique [0002] In order to adapt to the working conditions in the alpine regions of northern my country, the yield strength of many engineering special vehicle beam structures is required to exceed 590MPa, and the tensile strength of high-strength steel exceeds 700MPa. The manufacturing process and the use process require bending and welding. In the alpine belts of Inner Mongolia, Jilin, Heilongjiang, etc., to ensure the stability of the equipment structure, high strength and light weight, reducing the thickness of steel plates, a large number of 6-50mm high-strength structural medium and thick steel plates are required. Therefore, the technical requirements for stable quality, high strength, good low temperature impact toug...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/16C22C38/12C22C33/04C21D8/02
Inventor 冯勇周兰聚侯登义侯东华贾慧领贾希光谢晖宋雷明
Owner SHANDONG IRON & STEEL CO LTD
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