Super double-phase stainless steel tube and production process thereof

A duplex stainless steel and super technology, applied in the field of super duplex stainless steel pipe and its production process, can solve the problems of insufficient dissolution of carbides, excessive corrosion rate, excessive hardness, etc., and achieve good strong plasticity, uniform distribution, and microstructure size. small effect

Active Publication Date: 2015-02-04
江苏鑫常特材有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the prior art, carbides cannot be fully dissolved in the production process of duplex stainless steel, and the precipitation of carbides between grains causes intergranular corrosion and pitting corrosion to exceed the standard, and uneven solid solution will lead to excessive corrosion rate and excessive hardness

Method used

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  • Super double-phase stainless steel tube and production process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] This embodiment is a super duplex stainless steel pipe, its chemical composition and mass percentage are: Ni: 7.6%, Mo: 4.2%, Cr: 22.1%, C: 0.015%, Si: 0.045%, Mn: 0.3%, S: 0.02%, P: 0.035%, Cu: 0.03%, Co: 0.012%, O: 0.03%, Al: 0.3%, Nb: 0.07%, B: 0.001%, N: 0.03%, and the balance is Fe.

[0028] The production process of the super duplex stainless steel pipe in this embodiment, its process line is: tube blank→peeling and sawing→heating→perforation→first pickling→waste pipe inspection→first cold rolling→first degreasing→first heat treatment →First straightening and cutting of pipes→First cooling→Second pickling→Intermediate inspection→Second cold rolling→Second degreasing→Second heat treatment→Bend pipe and elbow heat treatment→Second cooling→Second straightening and cutting →Third pickling→Product surface inspection→Ultrasonic flaw detection→Eddy current flaw detection→Spray marking→Packaging;

[0029] The first heat treatment process: using segmental heating, the hea...

Embodiment 2

[0036] This example is a super duplex stainless steel pipe, Ni: 7.7%, Mo: 4.3%, Cr: 22.2%, C: 0.017%, Si: 0.048%, Mn: 0.4%, S: 0.01%, P: 0.015 %, Cu: 0.04%, Co: 0.015%, O: 0.04%, Al: 0.4%, Nb: 0.08%, B: 0.002%, N: 0.04%, and the balance is Fe.

[0037] The production process of the super duplex stainless steel pipe in this embodiment, its process line is: tube blank→peeling and sawing→heating→perforation→first pickling→waste pipe inspection→first cold rolling→first degreasing→first heat treatment →First straightening and cutting of pipes→First cooling→Second pickling→Intermediate inspection→Second cold rolling→Second degreasing→Second heat treatment→Bend pipe and elbow heat treatment→Second cooling→Second straightening and cutting →Third pickling→Product surface inspection→Ultrasonic flaw detection→Eddy current flaw detection→Spray marking→Packaging;

[0038] The first heat treatment process: using segmental heating, the heating temperature of the first heating stage is 888°C...

Embodiment 3

[0045] This example is a super duplex stainless steel pipe, Ni: 7.8%, Mo: 4.5%, Cr: 22.3%, C: 0.018%, Si: 0.05%, Mn: 0.5%, S: 0.01%, P: 0.015 %, Cu: 0.05%, Co: 0.016%, O: 0.05%, Al: 0.5%, Nb: 0.09%, B: 0.003%, N: 0.05%, and the balance is Fe.

[0046] The production process of the super duplex stainless steel pipe in this embodiment, its process line is: tube blank→peeling and sawing→heating→perforation→first pickling→waste pipe inspection→first cold rolling→first degreasing→first heat treatment →First straightening and cutting of pipes→First cooling→Second pickling→Intermediate inspection→Second cold rolling→Second degreasing→Second heat treatment→Bend pipe and elbow heat treatment→Second cooling→Second straightening and cutting →Third pickling→Product surface inspection→Ultrasonic flaw detection→Eddy current flaw detection→Spray marking→Packaging;

[0047] The first heat treatment process: using segmental heating, the heating temperature of the first heating stage is 890°C,...

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Abstract

The invention discloses a super double-phase stainless steel tube and a production process thereof. The super double-phase stainless steel tube comprises the following components in percentage by weight: 7.6%-7.8% of Ni, 4.2%-4.5% of Mo, 22.1%-22.3% of Cr, 0.015%-0.018% of C, 0.045%-0.05% of Si, 0.3%-0.5% of Mn, more than 0 and not more than 0.02% of S, more than 0 and not more than 0.035% of P, 0.03%-0.05% of Cu, 0.012%-0.016% of Co, 0.03%-0.05% of O, 0.3%-0.5% of Al, 0.07%-0.09% of Nb, 0.001%-0.003% of B, 0.03%-0.05% of N and the balance being Fe. The production process can be used for sufficiently dissolving and uniformly dispersing carbide by virtue of two heating steps and two cooling steps, so that inter-crystalline corrosion and point corrosion caused by precipitation of the carbide among the crystals are avoided; moreover, the super double-phase stainless steel tube has good strong plasticity.

Description

technical field [0001] The invention relates to a production process of a stainless steel pipe, in particular to a super duplex stainless steel pipe and the production process thereof. Background technique [0002] The so-called duplex stainless steel is that in its solid solution structure, the ferrite phase and austenite phase account for about half, and the content of the general amount of minor phase also needs to reach 30%. This type of steel has the characteristics of both austenitic and ferritic stainless steels. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, significantly improved intergranular corrosion resistance and welding performance, while maintaining iron The body stainless steel is brittle at 475°C, has high thermal conductivity, and has the characteristics of superplasticity. Compared with austenitic stainless steel, it has high strength and significantly improved resistance to intergranular corrosion and chl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/54C21D8/10
Inventor 郁宇新
Owner 江苏鑫常特材有限公司
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