Corrosion resistant duplex steel alloy, objects made thereof, and method of making the alloy
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B01J-019/00
B01J-019/02
B01J-019/24
B22F-003/15
C07C-273/04
C22C-033/02
C22C-038/00
C22C-038/02
C22C-038/04
C22C-038/18
C22C-038/40
C22C-038/42
C22C-038/44
C22C-038/58
F28F-021/08
출원번호
US-0108549
(2014-12-23)
등록번호
US-10046297
(2018-08-14)
우선권정보
EP-13199704 (2013-12-27)
국제출원번호
PCT/NL2014/050902
(2014-12-23)
국제공개번호
WO2015/099530
(2015-07-02)
발명자
/ 주소
Larsson, Linn
Gullberg, Daniel
Kivisäkk, Ulf
Östlund, Martin
Scheerder, Alexander Aleida Antonius
출원인 / 주소
Stamicarbon B.V.
대리인 / 주소
Morrison & Foerster LLP
인용정보
피인용 횟수 :
0인용 특허 :
3
초록▼
Disclosed is a Hot Isostatic Pressed ferritic-austenitic steel alloy, as well objects thereof. The elementary composition of the alloy comprises, in percentages by weight: C 0-0.05; Si 0-0.8; Mn 0-4.0; Cr more than 29-35; Ni 3.0-10; Mo 0-4.0; N 0.30-0.55; Cu 0-0.8; W 0-3.0; S 0-0.03; Ce 0-0.2; the b
Disclosed is a Hot Isostatic Pressed ferritic-austenitic steel alloy, as well objects thereof. The elementary composition of the alloy comprises, in percentages by weight: C 0-0.05; Si 0-0.8; Mn 0-4.0; Cr more than 29-35; Ni 3.0-10; Mo 0-4.0; N 0.30-0.55; Cu 0-0.8; W 0-3.0; S 0-0.03; Ce 0-0.2; the balance being Fe and unavoidable impurities. The objects can be particularly useful in making components for a urea production plant that require processing such as machining or drilling. A preferred use is in making, or replacing, liquid distributors as used in a stripper as is typically present in the high-pressure synthesis section of a urea plant.
대표청구항▼
1. A method to prepare a component for a urea manufacturing plant, wherein the component is in contact with a fluid selected from the group consisting of carbamate solutions and gases containing ammonia and carbon dioxide, as present in the synthesis section of said plant under condensing conditions
1. A method to prepare a component for a urea manufacturing plant, wherein the component is in contact with a fluid selected from the group consisting of carbamate solutions and gases containing ammonia and carbon dioxide, as present in the synthesis section of said plant under condensing conditions from an object obtainable by subjecting a ferritic-austenitic steel alloy powder to hot isostatic pressing, wherein the ferritic-austenitic steel powder consists of, in percentages by weight: C 0-0.05;Si 0-0.8;Mn 0-4.0;Cr26-35;Ni3.0-10; Mo 0-4.0;N0.30-0.55;Cu 0-1.0;W 0-3.0;S 0-0.03;Ce 0-0.2;the balance being Fe and unavoidable impurities; said method comprising processing the object by a technique selected from the group consisting of machining, drilling, and combinations thereof, said component comprising one or more surfaces resulting from said processing. 2. The method of claim 1, wherein, in the ferritic-austenitic steel alloy, the austenite spacing, as determined on a sample by DNV-RP-F112, Section 7, using the sample preparation according to ASTM E 3-01, is smaller than 20 μm; and wherein the largest average austenite phase length/width ratio selected from the average austenite phase length/width ratio determined in three cross-sections of a sample as needed, the cross-sections taken at three perpendicular planes of a sample is smaller than 5; the average austenite phase length/width ratio being determined by the following procedure: i. preparing the cross-cuts surfaces of the sample;ii. polishing the surfaces using diamond paste on a rotating disc with a particle size of first 6 μm and subsequently 3 μm to create a polished surface;iii. etching the surfaces using Murakami's agent for up to 30 seconds at 20° C. thereby coloring the ferrite phase, the agent being provided by preparing a saturated solution by mixing 30 g potassium hydroxide and 30 g K3Fe(CN)6 in 100 ml H2O, and allowing the solution to cool down to room temperature before use;iv. observing the cross-cut surfaces in etched condition under an optical microscope with a magnification selected such that phase boundaries are distinguishable;v. projecting a cross-grid over the image, wherein the grid has a grid distance adapted to observe the austenite-ferrite phase boundaries;vi. randomly selecting at least ten grid crossings on the grid such that the grid crossings can be identified as being in the austenite phase;vii. determining, at each of the ten grid crossings, the austenite phase length/width ratio by measuring the length and the width of the austenite phase, wherein the length is the longest uninterrupted distance when drawing a straight line between two points at the phase boundary, the phase boundary being the transition from an austenitic phase to the ferrite phase; and wherein the width is defined as the longest uninterrupted distance measured perpendicular to the length in the same phase;calculating the average austenite phase length/width ratio as the numerical average of the austenite phase length/width ratios of the ten measured austenite phase length/width ratios. 3. The method of claim 2, wherein the sample on which the measurement is performed has at least one dimension of greater than 5 mm. 4. The method of claim 2, wherein said austenite spacing is smaller than 15 μm. 5. The method of claim 1, wherein the elementary composition of the alloy consists of, in percentages by weight: C 0-0.030;Mn 0.8-1.50;S 0-0.03;Si 0-0.50;Cr 28.0-30.0;Ni5.8-7.5;Mo1.50-2.60;W 0-3.0Cu 0-0.80;N0.30-0.40 Ce 0-0.2;the balance being Fe and unavoidable impurities. 6. The method of claim 1, wherein the elementary composition consists of, in percentages by weight: C 0-0.03;Si 0-0.5;Mn0.3-1; Cr29-33;Ni 3-10;Mo1.0-1.3;N0.36-0.55;Cu 0-1.0;W 0-2.0;S 0-0.03;Ce 0-0.2;the remainder being Fe and unavoidable impurities, the ferrite content being 30-70% by volume. 7. The method of claim 1, wherein the component is selected from the group consisting of a liquid distributor, a radar cone, a (control) valve, and an ejector. 8. The method of claim 7, wherein said one or more surfaces are the drilled holes of the liquid distributor. 9. A method of modifying an existing plant for the production of urea, said plant comprising one or more components to be replaced selected from the group consisting of liquid distributors, radar cones, (control) valves and ejectors, the method comprising replacing one or more of the components to be replaced by a corresponding replacement component, wherein said replacement component is prepared by the method of claim 1. 10. The method of claim 9, wherein the component to be replaced is made from a ferritic-austenitic steel alloy having an elementary composition which consists of, in percentages by weight: C 0-0.05;Si 0-0.8;Mn 0-4.0;Cr26-35;Ni 3.0-10; Mo 0-4.0;N0.30-0.55;Cu 0-1.0;W 0-3.0;S 0-0.03;Ce 0-0.2;the balance being Fe and unavoidable impurities;wherein the replacement component has been subjected to a processing technique selected from the group consisting of machining, drilling and combinations thereof. 11. The method of claim 10, wherein the existing plant comprises a stripper, the tubes and liquid distributors of which are made from said ferritic-austenitic alloy, and wherein said replaced components are said liquid distributors.
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이 특허에 인용된 특허 (3)
Yamadera,Yoshimi; Nagashima,Eiki, Duplex stainless steel for urea manufacturing plants.
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