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Duplex stainless steels and their uses

A technology of duplex stainless steel and purpose, applied in the field of urea production and transformation of existing urea production equipment, can solve the problems not mentioned, and achieve the effect of excellent corrosion resistance

Active Publication Date: 2022-02-01
SAIPEM SPA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The proposed alloy is intended for use in the onshore and offshore sectors of the oil and gas industry, but does not mention use in more severe corrosive conditions such as in urea equipment / processes

Method used

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  • Duplex stainless steels and their uses
  • Duplex stainless steels and their uses

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Embodiment

[0156] Expressed in weight percent, an exemplary steel composition according to the present invention comprises:

[0157] C: 0.03% or less;

[0158] Si: 0.5% or less;

[0159] Mn: 2.5% or less;

[0160] Cr: 30.5% to 35%;

[0161] Ni: 5.5% to 8%;

[0162] Mo: 2% to 2.5%;

[0163] W: 0.02% to 1.0%;

[0164] Co: 0.01% to 0.8%;

[0165] N: 0.3% to 0.6%;

[0166] Cu: 1% or less;

[0167] One or more of the following:

[0168] Ca: 0.004% or less;

[0169] Mg: 0.004% or less;

[0170] One or more rare earth elements in a total amount of 0.05% or less;

[0171] The rest is Fe and unavoidable impurities;

[0172]Satisfy the relationship: Z=1.062*(Ni+Co)+4.185*Mo between 14.95 and 19.80.

[0173] Expressed in weight percent, other embodiments of the steel of the present invention include:

[0174] C: 0.001% to 0.03%;

[0175] Si: 0.001% to 0.5%;

[0176] Mn: 0.001% to 2.5%;

[0177] Cr: higher than 30% to 35%;

[0178] Ni: 5.5% to 8%;

[0179] Mo: 2% to 2.5%;

[0180...

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Abstract

Provided is a duplex stainless steel for use in urea production equipment and / or in urea production process, which contains by weight percentage (%w): C 0.03 or lower; Si 0.5 or lower; Mn 2.5 or higher Low; Cr higher than 30.0 to 35.0; Ni 5.5 to 8.0; Co 0.01 to 0.8; Mo 2.0 to 2.5; W 2.5 or lower; N 0.3 to 0.6; Cu 1.0 or lower; species: Ca 0.0040 or lower; Mg 0.0040 or lower; one or more rare earth elements with a total amount of 0.1 or lower; the rest are Fe and impurities; and satisfy the following relationship: Z=1.062(Ni+Co)+ 4.185Mo is between 14.95 and 19.80.

Description

[0001] Citations to related applications [0002] This patent application claims priority from European Patent Application No. 17210463.0 filed on December 22, 2017, the disclosure of which is incorporated by reference. technical field [0003] The invention relates to the use of duplex stainless steel in high-temperature and high-pressure high-temperature and high-pressure environment containing ammonium carbamate and highly corrosive urea. [0004] Therefore, the present invention also relates to the use of duplex stainless steel in urea plants (i.e. plants for the production of urea), and in particular in instruments, equipment or installations (or parts thereof) exposed to concentrated ammonium carbamate at high temperatures use. [0005] The invention also relates to an instrument, equipment or device of a urea production plant or used in a urea production process comprising at least one component made of corrosion-resistant duplex stainless steel. [0006] The inventio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/00C22C38/02C22C38/04C22C38/42C22C38/44C22C38/58C22C38/52B01D3/32B01J19/02B22F3/15C07C273/04
CPCB01D1/00B01D1/30B01D3/32B01D5/00B01D5/0033B01J19/02C07C273/04C21D6/004C21D6/005C22C38/001C22C38/002C22C38/004C22C38/005C22C38/02C22C38/04C22C38/42C22C38/44C22C38/52C22C38/58B01J2219/0286C21D2211/001C21D2211/005Y02P20/141C07C273/02C07C275/02
Inventor 朱利奥·帕奇马拉·夸特罗基利诺·卡尔丽丝阿尔贝托·塞拉费罗
Owner SAIPEM SPA