A thick-gauge x80 pipe fitting steel pipe with excellent low-temperature toughness and preparation method thereof

A low-temperature toughness and thick-gauge technology, which is applied in the field of thick-gauge X80 pipe fitting steel pipes and its preparation, can solve the problems that the influence of low-temperature toughness of pipe fitting steel is not considered, and it is difficult to ensure the low-temperature toughness of pipe fitting steel plates stably, so as to solve the process window Narrow, excellent low temperature toughness, the effect of excellent low temperature toughness

Inactive Publication Date: 2018-02-02
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The influence of Ti / Al ratio and Al / N ratio on the low-temperature toughness of pipe steel is not taken into account in the prior art, nor is the composition design, forming process parameters, pre-welding, internal and external welding process, diameter expanding process and heat treatment key points systematically considered. The influence of the process on the low-temperature toughness of the pipe fitting steel only involves some process parameters, without considering the connection and coordination of each process as a whole, it is difficult to ensure the low-temperature toughness of the pipe fitting steel plate stably

Method used

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  • A thick-gauge x80 pipe fitting steel pipe with excellent low-temperature toughness and preparation method thereof
  • A thick-gauge x80 pipe fitting steel pipe with excellent low-temperature toughness and preparation method thereof
  • A thick-gauge x80 pipe fitting steel pipe with excellent low-temperature toughness and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The thick-gauge X80 fitting steel pipe with excellent low-temperature toughness is prepared from the following components in mass percentage: C: 0.04%, Si: 0.20%, Mn: 1.70%, P=0.005%, S=0.001%, Nb: 0.035%, Mo: 0.20%, Cu: 0.10%, Cr: 0.15%, Ni: 0.15%, Ti: 0.03%, Al: 0.01%, N=0.002%, Ti / Al=3, Al / N=5, V:0.02%, Pcm=0.16%, Ceq=0.41%.

[0036] The balance is Fe and unavoidable impurities.

[0037] The preparation method is as follows:

[0038] 1) Steel plate milling and forming process: Both sides of the steel plate are milled at 20mm. The steel plate adopts the JCOE forming process. First, the steel plate is pressed into a "J" shape, and then the other half of the steel plate is pressed into a "C" shape, and finally the opening is formed. "O" shape, a total of 21 stamping passes, including 4 passes for pressing "J" shape, 13 passes for "C" shape, 4 passes for pressing "O" shape, after each pass is pressed The next pass of deformation is carried out with an interval of 5 se...

Embodiment 2

[0046] The thick-gauge X80 fitting steel pipe with excellent low-temperature toughness is prepared from the following components by mass percentage: C: 0.07%, Si: 0.30%, Mn: 1.90%, P=0.010%, S=0.005%, Nb: 0.070%, Mo: 0.25%, Cu: 20%, Cr: 0.25%, Ni: 0.30%, Ti: 0.04%, Al: 0.02%, N=0.005%, Ti / Al=3, Al / N=2, V:0.04%, Pcm=0.22%, Ceq=0.53%.

[0047] The preparation method is as follows:

[0048] 1) Steel plate milling and forming process: Both sides of the steel plate are milled at 20mm. The steel plate adopts the JCOE forming process. First, the steel plate is pressed into a "J" shape, and then the other half of the steel plate is pressed into a "C" shape, and finally the opening is formed. "O" shape, a total of 23 stamping passes, including 5 passes for pressing "J" shape, 15 passes for "C" shape, 3 passes for pressing "O" shape, after each pass is pressed Intermittent 6 seconds to carry out the next pass of deformation, the reduction of each pass is carried out in an incremental ...

Embodiment 3

[0056] The thick-gauge X80 fitting steel pipe with excellent low-temperature toughness is prepared from the following components by mass percentage: C: 0.05%, Si: 0.25%, Mn: 1.80%, P=0.008%, S=0.002%, Nb: 0.050%, Mo: 0.20%, Cu: 0.15%, Cr: 0.20%, Ni: 0.20%, Ti: 0.031%, Al: 0.015%, N=0.004%, Ti / Al=2, Al / N=3.75, V:0.03%, Pcm=0.19%, Ceq=0.46%.

[0057] The preparation method is as follows:

[0058]1) Steel plate milling and forming process: Both sides of the steel plate are milled at 20mm. The steel plate adopts the JCOE forming process. First, the steel plate is pressed into a "J" shape, and then the other half of the steel plate is pressed into a "C" shape, and finally the opening is formed. "O" shape, a total of 23 stamping passes, including 4 passes for pressing "J" shape, 14 passes for "C" shape, 5 passes for pressing "O" shape, after each pass is pressed Intermittently 5.5 seconds to carry out the next pass of deformation, the reduction of each pass is carried out in an in...

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Abstract

The invention belongs to the technical field of manufacture of low-alloy high-strength steel pipes and particularly relates to a thick X80 steel pipe with excellent low-temperature toughness and a production method thereof. The thick X80 steel pipe with excellent low-temperature toughness is chemically composed of, by weight, 0.04-0.07% of C, 0.20-0.30% of Si, 1.70-1.90% of Mn, < / =0.01% of P, < / =0.005% of S, 0.035-0.070% of Nb, 0.20-0.25% of Mo, 0.10-0.20% of Cu, 0.15-0.25% of Cr, 0.15-0 is chemically composed of, by weight: 0.04-0.07% of C, 0.20-0.30% of Si, 1.70-1.90% of Mn, < / =0.01% of P, < / =0.005% of S, 0.035-0.070% of Nb, 0.20-0.25% of Mo, 0.10-0.20% of Cu, 0.15-0.25% of Cr, 0.15-0.30% of Ni, 0.03-0.04% of Ti, 0.01-0.02% of Al, < / =0.005% of N, 2< / =Ti / Al< / =3, 2< / =Al / N< / =5, 0.02-0.04% of V, and the balance of Fe and unavoidable impurities. The thick X80 steel pipe with excellent low-temperature toughness is produced by comprehensively using precision coiling, welding and thermal treatment processes by the aid of low-carbon multi-element microalloy composition design.

Description

technical field [0001] The invention belongs to the technical field of manufacturing low-alloy high-strength pipe fitting steel pipes, and in particular relates to a thick gauge X80 pipe fitting steel pipe with excellent low-temperature toughness and a preparation method thereof. Background technique [0002] With the continuous start of the oil pipeline industry, especially the start of the China-Russia East Line, the pipeline needs to pass through a series of geologically harsh areas such as alpine areas and permafrost. When laying pipelines in these areas, some low-temperature-resistant thick-gauge pipe fittings are required. Steel Pipe. Part of the pipe fittings required for the pipeline needs to be exposed to the temperature of -45°C, and the thickness of the pipe fittings should reach more than 50mm. This kind of pipe fitting steel is easy to work and harden due to the high alloy content when the steel plate is coiled. On the basis of ensuring the strength of the steel...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/12C22C38/16C22C38/18C22C38/08C22C38/14C22C38/06C21D8/10
CPCC21D8/105C22C38/001C22C38/02C22C38/04C22C38/06C22C38/08C22C38/12C22C38/14C22C38/16C22C38/18
Inventor 牛延龙刘晓东刘志刚韩启彪于爽赵慧杰李柏君杜平薛艳龙
Owner SHANDONG IRON & STEEL CO LTD
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