Subsea pipeline steel L485MO with low yield ratio and low hardness and production method thereof

A subsea pipeline steel and low yield-strength ratio technology, which is applied to the low-yield-ratio and low-hardness submarine pipeline steel L485MO and its production field, can solve the problems of not reflecting the hardness value and yield ratio control level, reducing product economy, etc. To achieve the effect of increasing anti-cracking effect, strong anti-seawater corrosion ability, and improving safety

Pending Publication Date: 2021-08-20
HANDAN IRON & STEEL GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It only emphasizes the low-temperature CTOD effect, and precious metal V is added in the composition design, which reduces the economy of the product; its yield strength is 453-510

Method used

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  • Subsea pipeline steel L485MO with low yield ratio and low hardness and production method thereof
  • Subsea pipeline steel L485MO with low yield ratio and low hardness and production method thereof
  • Subsea pipeline steel L485MO with low yield ratio and low hardness and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] In this embodiment, the thickness of the submarine pipeline steel strip produced in this embodiment is 3mm, the total reduction under light reduction at the end of continuous casting solidification is 8mm, the rough rolling in the rolling process is rolled in 3+5 passes, and the reduction rate in the final pass of R2 rough rolling is 24 %, without throwing the frame, the specific composition of the continuous casting slab, other production process parameters and performance control are shown in Table 1:

[0034] Table 1 3mm thickness composition (wt%), process and performance

[0035]

[0036] figure 1 It shows that the subsea pipeline steel L485MO structure produced in Example 1 is irregular acicular ferrite, and the grain size rating is 13 grades; Table 1 shows that the product strength is moderate, and the tensile, bending, impact, metallographic, and drop Other experimental items meet the requirements of APISpec 5L (version 46) PSL2, the yield strength ratio and...

Embodiment 2

[0038] In this embodiment, the thickness of the L485MO steel strip for the production of the seabed pipeline steel is 3 mm, and the total reduction is 8 mm under light reduction at the end of continuous casting solidification. The production rate is 24%, the frame is not thrown, the specific composition of the continuous casting slab, other production process parameters and performance control are shown in Table 2:

[0039] Table 2 3mm thickness composition (wt%), process and performance

[0040]

[0041] figure 2 It shows that the subsea pipeline steel L485MO structure produced in Example 2 is irregular acicular ferrite, and the grain size rating is 13 grades; Table 2 shows that the product strength is moderate, and the tensile, bending, impact, metallographic, and drop weight Other experimental items meet the requirements of APISpec 5L (version 46) PSL2, the yield strength ratio and hardness value are low and stable, and the CTOD outsourced experiment is qualified.

Embodiment 3

[0043] In this embodiment, the thickness of the L485MO steel strip for the production of the seabed pipeline steel is 3 mm, and the total reduction is 8 mm under light reduction at the end of continuous casting solidification. The specific composition of continuous casting slab, other production process parameters and performance control are shown in Table 3:

[0044] Table 3 3mm thickness composition (wt%), process and performance

[0045]

[0046] image 3 It shows that the subsea pipeline steel L485MO structure produced in Example 3 is irregular acicular ferrite, and the grain size rating is 13 grades; Table 3 shows that the product strength is moderate, and the tensile, bending, impact, metallographic, and drop weight Other experimental items meet the requirements of APISpec 5L (version 46) PSL2, the yield strength ratio and hardness value are low and stable, and the CTOD outsourced experiment is qualified.

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Abstract

The invention relates to subsea pipeline steel L485MO with low yield ratio and low hardness. The subsea pipeline steel L485MO comprises the following chemical components in percentage by mass: 0.060-0.080% of C, 0.10-0.15% of Si, 1.50-1.70% of Mn, less than or equal to 0.008% of P, less than or equal to 0.001% of S, 0.015-0.035% of Als, 0.050-0.060% of Nb, 0.005-0.020% of Ti, 0.10-0.20% of Mo and the balance of Fe and inevitable impurities. The production method comprises a rolling process, rough rolling adopts 3+5 passes of rolling, the reduction rate of the last pass of R2 rough rolling is larger than or equal to 24%, and during finish rolling, 0-2 racks are determined to be thrown according to the thickness of produced strip steel, specifically, when the thickness of the strip steel is less than or equal to 8mm, the racks are not thrown; when the thickness of the strip steel is larger than 8mm and smaller than 13mm, one rack is thrown; and when the thickness of the strip steel is larger than or equal to 13mm, two racks are thrown. The hardness value of the produced pipeline steel is lower than the standard requirement upper limit value 30HV10, the yield ratio is smaller than or equal to 0.85, a finished product has high strength and toughness, high crack arrest resistance and seawater corrosion resistance, and the production cost is low.

Description

technical field [0001] The invention relates to a production method of pipeline steel, in particular to a low-yield-ratio low-hardness submarine pipeline steel L485MO and a production method thereof. Background technique [0002] Oil and natural gas are important energy sources for human beings, and the demand is increasing day by day. The distribution of oil and gas resources is getting farther and farther away from the concentration of consumption. The construction of low-cost, high-safety long-distance transmission pipelines plays a decisive role in the development of remote oil and gas fields. Improving the strength of pipeline steel can save a lot of investment and operating costs in material manufacturing, construction and installation, compression stations and other comprehensive aspects. In recent years, with the exploitation of large-scale oil and gas fields such as deserts, poles and seabeds, the service environment of pipelines is complex and changeable. Fracture...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14C22C33/04C21C7/06C21D8/02
CPCC22C38/02C22C38/04C22C38/06C22C38/12C22C38/14C22C33/04C21C7/06C21D8/0205C21D8/0226C21D2211/005
Inventor 孙毅李俊生李红俊张继永裴庆涛亢庆锋申建军
Owner HANDAN IRON & STEEL GROUP
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