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A preparation method of large diameter x80 longitudinal submerged arc welded pipe

A technology of straight seam submerged arc welding and large diameter, which is applied in the field of pipeline steel production, can solve problems such as the performance difference between plate and tube, and achieve the effect of small performance difference, reducing internal stress and reducing quantity

Active Publication Date: 2020-06-12
HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It can be seen that the existing large-diameter X80 longitudinal submerged arc welded pipe manufacturing process makes the performance difference between the plate and the pipe very obvious

Method used

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  • A preparation method of large diameter x80 longitudinal submerged arc welded pipe
  • A preparation method of large diameter x80 longitudinal submerged arc welded pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Example 1: The thickness of the steel plate is 25.7 mm, and the diameter of the steel pipe is φ 1422mm.

[0017] The chemical composition mass percentage of steel is: C=0.04, Si=0.19, Mn=1.69, P=0.011, S=0.0014, Als=0.027, Nb=0.056, Ti=0.018, V=0.003, Cr=0.17, Mo= 0.20, Ni=0.19, Cu=0.13, B=0.0003, N=0.0036, the balance is Fe and inevitable impurities, of which Ti / N=5.86.

[0018] The key process steps of the preparation method include:

[0019] (1) Steel plate rolling: Two-stage controlled rolling is adopted, the end temperature of rough rolling is 1092 °C, the starting temperature of finishing rolling is 910 °C, and the final rolling temperature is 800 °C; relaxation after rolling is 60s; cooling rate is 14~ 16℃ / s, the temperature of returning to red is 430~480℃;

[0020] (2) Tempering of steel plate: the tempering temperature is 450℃;

[0021] (3) Steel pipe forming, diameter expansion, hydrostatic pressure: the number of JCOE forming steps is 25; the diameter exp...

Embodiment 2

[0031] Example 2: The thickness of the steel plate is 30.8 mm, and the diameter of the steel pipe is φ The chemical composition mass percentage of 1422mm steel is: C=0.03, Si=0.22, Mn=1.70, P=0.009, S=0.0015, Als=0.031, Nb=0.062, Ti=0.017, V=0.020, Cr=0.18, Mo = 0.20, Ni = 0.28, Cu = 0.15, B = 0.0003, N = 0.0029, the balance is Fe and inevitable impurities, where Ti / N = 5.0.

[0032] The key process steps of the preparation method include:

[0033] (1) Steel plate rolling: Two-stage controlled rolling is adopted, the end temperature of rough rolling is 1080°C, the starting temperature of finishing rolling is 890°C, and the final rolling temperature is 808°C; relaxation after rolling is 50s; cooling rate is 12~ 14℃ / s, the temperature of returning to red is 420~460℃;

[0034] (2) Tempering of steel plate: the tempering temperature is 425℃;

[0035] (3) Steel pipe forming, diameter expansion, hydrostatic pressure: the number of JCOE forming steps is 28; the diameter expansion ...

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Abstract

A manufacturing method of a large-diameter X80 longitudinal submerged arc welding pipe is characterized in that steel comprises the following chemical components in percentage by mass: not greater than 0.05% of C, not greater than 0.30% of Si, not greater than 1.80% of Mn, not greater than 0.015% of P, not greater than 0.005% of S, 0.015-0.050% of Als, 0.040-0.080% of Nb, 0.008-0.025% of Ti, not greater than 0.030% of V, not greater than 0.030% of Cr, not greater than 0.30% of Mo, 0.20-0.40% of Ni, not greater than 0.30% of Cu, not greater than 0.0005% of B, not greater than 0.0040% of N, notless than 3.42% of Ti / N, and the balance Fe and inevitable impurities. The key technical steps include the steps of rolling of a steel sheet, annealing of the steel sheet, molding, diameter expandingand static water pressing of the steel pipe, and annealing of the steel pipe. According to the method, the performance difference between a sheet and a pipe which are manufactured through the X80 pipeline steel is small; the yield intensities of the steel sheet and the steel pipe are not less than 555MPa, and the yield intensity difference is not greater than 20MPa; the DWTT hammering fracture FATT85 temperature is similar, so that the DWTT hammering cracking performance of the steel pipe can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of pipeline steel production, in particular to a preparation method of a large-diameter X80 straight seam submerged arc welded pipe. Background technique [0002] Pipeline transportation has many advantages such as high efficiency, safety, reliability, economy, one-way, continuous, environmental protection, etc. It is the most economical and reasonable transportation method for long-distance transportation of oil and natural gas. At present, large diameter and high pressure have become the basic direction of pipeline engineering construction. High pressure means higher requirements for the strength of pipeline steel. In recent years, X80 has begun to be put into use in batches, such as the Cheyenne gas pipeline in the United States, the Bafalianko-Uqa natural gas pipeline in Russia, and the West China gas pipeline in China. East gas pipeline, etc. Large-diameter X80 pipeline steel can significantly improve...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/58C22C38/04C22C38/06C22C38/48C22C38/50C22C38/46C22C38/44C22C38/42C22C38/54C21D8/02C21D9/08C21D1/18B23P15/00
CPCB23P15/00C21D1/18C21D8/0205C21D8/0226C21D8/0247C21D9/08C22C38/001C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58
Inventor 彭宁琦罗登蒋凌枫史术华熊祥江
Owner HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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