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A 780mpa level molybdenum boron high strength structural steel plate and its manufacturing method

A technology for structural steel plates and grades, which is applied in the field of molybdenum-containing, improved steel strength and toughness, and boron alloy design. It can solve problems such as uneven low-temperature toughness, poor welding performance, and poor plate shape, and achieve excellent strength and toughness matching and low cost. , the effect of good plate shape

Inactive Publication Date: 2016-07-13
JIGANG GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the 780MPa grade high-strength steel produced in the United States and Germany contains 0.60% nickel, 0.045% vanadium, and more than 0.35% molybdenum; the domestic popular TMCP produces more than 060% high chromium, more than 0.40% high molybdenum, and more than 0.45% high nickel , high niobium 0.040% or more, high cost, uneven low temperature toughness, range 36-230J, carbon equivalent higher than 0.71%, poor welding performance (requires pre-welding preheating, post-welding heat preservation or post-welding treatment, etc.), plate shape Poor, straightness is 8-11mm / m, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The slab smelting composition is:

[0033] C: 0.15%, Si: 0.26%, Mn: 1.40%, P: 0.015%, S: 0.003%, Cu: 0.21%, B: 0.0016%, Mo: 0.18%, Ti: 0.022%, the rest is Fe and not Avoid impurities.

[0034] Its detailed process steps are:

[0035] (1) Refining outside the LF furnace: heating time is 15 minutes, white slag is desulfurized, and titanium microalloy with a content of 0.022% is added;

[0036] (2) RH vacuum degassing: vacuum treatment below 200Pa for 20 minutes, soft blowing with argon gas for 10 minutes after feeding the wire; finally adding boron-iron alloy for protection; boron: 0.0016%;

[0037] (3) Continuous casting: Ladle to tundish, tundish to crystallizer respectively use argon and mold flux to protect casting, casting temperature 1530℃, casting speed 0.7m / min.

[0038] (4) Slab heating: the soaking temperature range is 1120°C, and the soaking time range is 3.3 hours; by using finely dispersed TiN particles and low-temperature heating to suppress the growth of...

Embodiment 2

[0049] The slab smelting composition is:

[0050] C: 0.15%, Si: 0.26%, Mn: 1.40%, P: 0.015%, S: 0.003%, Ti: 0.025%, Cu: 0.21%, B: 0.0016%; Mo: 0.18%; the rest is Fe and not Avoid impurities.

[0051] Its detailed process steps are:

[0052] (1) Refining outside the LF furnace: heating time is 20 minutes, white slag is desulfurized, and titanium microalloy with a content of 0.025% is added;

[0053] (2) VD vacuum degassing: vacuum treatment below 200Pa for 20 minutes, soft blowing with argon gas for 10 minutes after feeding the wire; finally adding boron-iron alloy for protection; boron: 0.0016%;

[0054] (3) Continuous casting: ladle to tundish, tundish to crystallizer respectively using argon and mold flux to protect casting, casting temperature 1560℃, casting speed 1.35m / min.

[0055] (4) Slab heating: the soaking temperature range is 1150°C, and the soaking time range is 3.5 hours; the growth of austenite grains is suppressed by using finely dispersed TiN particles and l...

Embodiment 3

[0064] C: 0.18%, Si: 0.29%, Mn: 1.70%, P: 0.017%, S: 0.001%, Ti: 0.023%, Cu: 0.14%, B: 0.0026%; Mo: 0.28%; the rest is Fe and not Avoid impurities.

[0065] Its detailed process steps are:

[0066] (1) Refining outside the LF furnace: heating time is 20 minutes, white slag is desulfurized, and titanium microalloy with a content of 0.023% is added;

[0067] (2) VD vacuum degassing: vacuum treatment below 200Pa for 20 minutes, soft blowing with argon gas for 10 minutes after feeding the wire; finally adding boron-iron alloy for protection; boron: 0.0026%;

[0068] (3) Continuous casting: Ladle to tundish, tundish to crystallizer respectively use argon and mold flux to protect casting, casting temperature 1550℃, casting speed 1.0m / min.

[0069] (4) Slab heating: the soaking temperature range is 1120°C, and the soaking time range is 3.6 hours; by using finely dispersed TiN particles and low-temperature heating to suppress the growth of austenite grains, obtain fine and uniform a...

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Abstract

The present invention relates to the process technology of strength and toughness and plate shape control of 6-120mm and 780MPa grade high-strength structural steel plate. It is a method of improving the strength and toughness of steel by using controlled rolling, quenching and tempering technology to design an alloy containing molybdenum and boron. . Its composition consists of the following components calculated by weight percentage: carbon: 0.07‑0.28%; silicon: 0.10‑0.45%; manganese: 0.80‑1.90%; copper≤0.55%; phosphorus≤0.025%; sulfur≤0.010%; titanium : 0.018‑0.040%; boron: 0.0010‑0.0035%; molybdenum: 0.10‑0.50%; the rest is Fe and unavoidable impurities. After refining outside the furnace and degassing refining, the purity of molten steel is improved, and a method for improving steel strength, toughness and flatness of steel plates through rolling, quenching and tempering techniques is provided to obtain tempered sorbite metallographic structure, carbon The equivalent is controlled within 0.52% to improve welding performance. The method has short flow, high efficiency, easy operation, easy welding and low cost.

Description

technical field [0001] The present invention relates to the process technology of strength toughness and plate shape control of 6-120mm specification 780MPa grade high-strength structural steel plate. . Background technique [0002] The yield strength of fully hydraulic road cranes, fire ladders, hydraulic supports, large mining vehicles, crawler cranes and high-rise rescue special vehicles with extension arms and frames, outriggers, and alternating stress structures exceeds 690MPa, and the tensile strength exceeds 780MPa Grade high-strength steel, the manufacturing process and the use process require the telescopic arm to be straight and free of contact friction, and in order to lift higher and lift more objects, ensure the rigidity of the structure, high strength and light weight, reduce the thickness of the steel plate, and require a large amount of 6-120mm high-strength structural medium-thick steel plate. Therefore, the technical requirements of stable quality, high s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/14C22C33/04C21D8/02
Inventor 冯勇孙卫华孙德民刘晓东周兰聚韩启彪贾慧领刘凤兰侯登义李善磊谢晖
Owner JIGANG GRP