A thick-gauge pipeline steel and its low compression ratio production process

A technology with low compression ratio and thick specifications, which is applied in the field of low-carbon micro-alloy steel materials, can solve the problems that the drop hammer toughness cannot meet the standard requirements, segregation and porosity in the core of continuous casting slabs, and easy coarse grains, etc. The effect of solving the macro segregation problem, improving the matching of strength and toughness, and reducing the purchase cost

Active Publication Date: 2022-01-25
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The main purpose of the present invention is to aim at the low compression ratio production process of the existing ultra-thick wall pipeline steel, which easily leads to coarse grains, segregation and looseness in the core of the continuous casting slab, low strength and toughness, especially the drop hammer toughness (DWTT) is difficult to meet Insufficient standard requirements, etc., provide a low compression ratio production method for thick gauge pipelines, the obtained pipeline steel meets the service technical requirements of pipeline steel such as extra thick wall, high strength and toughness, and the production process involved is simple, easy to operate, suitable for popularization and application

Method used

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  • A thick-gauge pipeline steel and its low compression ratio production process
  • A thick-gauge pipeline steel and its low compression ratio production process
  • A thick-gauge pipeline steel and its low compression ratio production process

Examples

Experimental program
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Effect test

Embodiment 1~4

[0052] 150mm billet is used to roll 25mm thickness X70 grade seabed acid-resistant pipeline steel. The specific implementation steps are as follows:

[0053] 1) Carry out smelting according to the composition requirements stated in Table 1, and control the content of molten steel as follows: N≤0.0050%, H≤0.0002%, O≤0.0025%, P≤0.015%, S≤0.0030%; molten steel composition After qualified, the molten steel is treated with Mg, the Mg in the molten steel is controlled at 0.0002-0.0022%, and the casting temperature is controlled at 1533-1548°C. At the same time, electromagnetic stirring and light reduction technology are used during the continuous casting solidification process to reduce the composition and Organization macro segregation;

[0054] 2) After casting a slab with a thickness of 150mm, install a heating furnace to heat and keep it warm; the heating temperature is 1160-1200°C; according to different furnace loading temperatures, the time in the furnace is 130-230min, and t...

Embodiment 5~9

[0066] Using 230mm billet to roll 40mm-41mmX70 grade pipeline steel, the specific implementation steps are as follows:

[0067] 1) Carry out smelting according to the composition requirements stated in Table 4, and control the content of molten steel as follows: N≤0.0050%, H≤0.0002%, O≤0.0025%, P≤0.015%, S≤0.0030%; molten steel composition After the molten steel composition is qualified, the molten steel is treated with Mg, the Mg in the molten steel is controlled at 0.0002-0.0022%, and the temperature is controlled at 1533-1548°C during casting. Reduce the composition and macro-segregation of the slab;

[0068] 2) After casting into a slab with a thickness of 230mm, install a heating furnace to heat and keep it warm; the heating temperature is 1160-1200°C; according to different furnace loading temperatures, the time in the furnace is 160-260min, and the holding time at a high temperature of 1160-1200°C is 60-100min;

[0069] 3) Three-stage hot rolling; in the first stage, o...

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Abstract

The invention discloses a low-compression ratio thick-gauge pipeline steel, the chemical composition and mass percentage of which are: C 0.03-0.07%, Si 0.10-0.30%, Mn 1.1-1.6%, Cr 0.1-0.3%, Ni 0.1 ~0.4%, Mo 0.10~0.25%, Nb 0.04~0.07%, V≤0.03%, Ti 0.01~0.025%, Al 0.01~0.045%, Mg 0.002‑0.0022%, using clean steel smelting, continuous casting, and slab heating , Three-stage controlled rolling, and ultra-fast cooling process. The matrix structure of the obtained steel plate is granular bainite and acicular ferrite, which has good strength-toughness matching and low yield ratio, and has excellent resistance to HIC and SSCC acid corrosion, and can meet the thickness specification yield strength ≥ 485MPa pipeline steel and service technical requirements for acid-resistant pipelines.

Description

technical field [0001] The invention belongs to the technical field of low-carbon micro-alloy steel materials, and in particular relates to a thick-gauge pipeline steel and a production process thereof with a low compression ratio. Background technique [0002] China is a country that consumes a lot of energy. For the sake of high-efficiency energy transmission and safety considerations, high-grade steel, large-diameter, large-wall thickness, and high-pressure transmission have become important development directions for pipeline construction. The country urgently needs to develop high-grade steel pipes such as X70-X80 Wall thickness pipeline steel. [0003] Compared with conventional thin-gauge pipeline steel, the production of high-grade large-wall-thickness pipeline steel often adopts the method of grain refinement to ensure strength and toughness. By applying a large amount of compression to thick-gauge continuous casting slabs, grain refinement and The purpose of impro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/58C22C38/44C22C38/48C22C38/46C22C38/50C22C38/06C21D8/02
CPCC22C38/02C22C38/04C22C38/58C22C38/44C22C38/48C22C38/46C22C38/50C22C38/06C21D8/0226C21D2211/002C21D2211/005
Inventor 岳江波李利巍俆进桥邹航梅荣利邓伟张鹏武汪波聂顺刘静
Owner 武汉钢铁有限公司
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