Urea-class stainless steel pipe and production process thereof

A technology of stainless steel pipe and production process, which is applied in the field of production process of stainless steel pipe, can solve problems such as incomplete dissolution of carbides, excessive corrosion rate, intergranular corrosion, etc., and achieve good intergranular corrosion resistance and selective corrosion performance, good Corrosion resistance and the effect of stabilizing the austenite structure

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 urea-grade stainless steel, and the precipitation of carbides in the intergranular causes excessive intergranular corrosion and pitting corrosion, and uneven solid solution will lead to excessive corrosion rate and excessive hardness

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] This embodiment is a urea grade stainless steel pipe, its chemical composition and mass percentage are: Ni: 19.6%, Mo: 3.2%, Cr: 19.1%, C: 0.025%, Si: 1.3%, Mn: 1.7%, S : 0.03%, 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.

[0034] The production process of the urea-grade stainless steel pipe in this embodiment, its process line is: tube blank→solution treatment→peeling and sawing→heating→perforation→first pickling→waste tube inspection→first cold rolling→first degreasing→ First heat treatment→first straightening and cutting pipe→first cooling→second pickling→intermediate inspection→second cold rolling→second degreasing→second heat treatment→bend pipe and elbow heat treatment→second cooling→bright heat treatment→ The third cooling → the second straightening and cutting of pipes → the third pickling → surface inspection of finished products → ultrasonic flaw detection → eddy current flaw detection → spray mark...

Embodiment 2

[0046] This embodiment is a urea grade stainless steel pipe, its chemical composition and mass percentage are: Ni: 19.8%, Mo: 3.5%, Cr: 19.3%, C: 0.028%, Si: 1.5%, Mn: 1.9%, S : 0.05%, P: 0.037%, Cu: 0.05%, Co: 0.016%, 0: 0.05%, Al: 0.5%, Nb: 0.09%, B: 0.003%, N: 0.05%, and the balance is Fe.

[0047] The production process of the urea-grade stainless steel pipe in this embodiment, its process line is: tube blank→solution treatment→peeling and sawing→heating→perforation→first pickling→waste tube inspection→first cold rolling→first degreasing→ First heat treatment→first straightening and cutting pipe→first cooling→second pickling→intermediate inspection→second cold rolling→second degreasing→second heat treatment→bend pipe and elbow heat treatment→second cooling→bright heat treatment→ The third cooling → the second straightening and cutting of pipes → the third pickling → surface inspection of finished products → ultrasonic flaw detection → eddy current flaw detection → spray ma...

Embodiment 3

[0059] This embodiment is a urea grade stainless steel pipe, its chemical composition and mass percentage are: Ni: 19.7%, Mo: 3.3%, Cr: 19.2%, C: 0.027%, Si: 1.4%, Mn: 1.8%, S : 0.034%, P: 0.036%, Cu: 0.04%, Co: 0.014%, O: 0.04%, Al: 0.4%, Nb: 0.08%, B: 0.002%, N: 0.04%, and the balance is Fe.

[0060] The production process of the urea-grade stainless steel pipe in this embodiment, its process line is: tube blank→solution treatment→peeling and sawing→heating→perforation→first pickling→waste tube inspection→first cold rolling→first degreasing→ First heat treatment→first straightening and cutting pipe→first cooling→second pickling→intermediate inspection→second cold rolling→second degreasing→second heat treatment→bend pipe and elbow heat treatment→second cooling→bright heat treatment→ The third cooling → the second straightening and cutting of pipes → the third pickling → surface inspection of finished products → ultrasonic flaw detection → eddy current flaw detection → spray m...

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Abstract

The invention relates to a urea-class stainless steel pipe and a production process thereof. The urea-class stainless steel pipe comprises the following chemical components: 19.6 to 19.8 percent of Ni, 3.2 to 3.5 percent of Mo, 19.1 to 19.3 percent of Cr, 0.025 to 0.028 percent of C, 1.3 to 1.5 percent of Si, 1.7 to 1.9 percent of Mn, 0.03 to 0.05 percent of S, 0.035 to 0.037 percent of P, 0.03 to 0.05 percent of Cu, 0.012 to 0.016 percent of Co, 0.03 to 0.05 percent of O, 0.3 to 0.5 percent of Al, 0.07 to 0.09 percent of Nb, 0.001 to 0.003 percent of B, 0.03 to 0.05 percent of N and the balance of Fe. Due to two different procedures of heating and cooling, the steel pipe has excellent intercrystalline corrosion resistance and selective corrosion performance and has excellent strong plasticity.

Description

technical field [0001] The invention relates to a production process of a stainless steel pipe, in particular to a urea-grade stainless steel pipe and the production process thereof. Background technique [0002] Urea grade stainless steel is a special austenitic stainless steel. The urea grade stainless steel specially used for urea production mainly includes 316UG, 00Cr25Ni22Mo2N (2RE69). Urea production is under high pressure (140-250 atmospheric pressure) and temperature 180-210 degrees. Carbon dioxide and ammonia are synthesized, and the intermediate product ammonium carbamate is strongly corrosive to stainless steel. General stainless steel such as 316L cannot meet its corrosion resistance. The special steel bell developed from this is called urea grade stainless steel. Compared with traditional stainless steel, urea grade stainless steel has high strength, significantly improved intergranular corrosion resistance and chloride stress corrosion resistance, and has excel...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/60C22C38/58C21D8/10
Inventor 郁宇新
Owner 江苏鑫常特材有限公司
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