US3861908A - Duplex stainless steel - Google Patents
Duplex stainless steel Download PDFInfo
- Publication number
- US3861908A US3861908A US389832A US38983273A US3861908A US 3861908 A US3861908 A US 3861908A US 389832 A US389832 A US 389832A US 38983273 A US38983273 A US 38983273A US 3861908 A US3861908 A US 3861908A
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- US
- United States
- Prior art keywords
- percent
- max
- chromium
- carbon
- molybdenum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 229910001039 duplex stainless steel Inorganic materials 0.000 title claims abstract description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000011651 chromium Substances 0.000 claims abstract description 30
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 29
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 26
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 26
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 26
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 23
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 23
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000011733 molybdenum Substances 0.000 claims abstract description 21
- 230000007797 corrosion Effects 0.000 claims abstract description 16
- 238000005260 corrosion Methods 0.000 claims abstract description 16
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 15
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 14
- 239000011572 manganese Substances 0.000 claims abstract description 14
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 12
- 239000010703 silicon Substances 0.000 claims abstract description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052742 iron Inorganic materials 0.000 claims abstract description 5
- 229910000859 α-Fe Inorganic materials 0.000 claims description 19
- 229910001566 austenite Inorganic materials 0.000 claims description 17
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 238000000137 annealing Methods 0.000 claims description 3
- 229910045601 alloy Inorganic materials 0.000 description 14
- 239000000956 alloy Substances 0.000 description 14
- 239000000203 mixture Substances 0.000 description 12
- 230000000694 effects Effects 0.000 description 9
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 241000238366 Cephalopoda Species 0.000 description 1
- 101100457407 Neurospora crassa (strain ATCC 24698 / 74-OR23-1A / CBS 708.71 / DSM 1257 / FGSC 987) mmm-1 gene Proteins 0.000 description 1
- GEXAOYRHMSYOPM-UHFFFAOYSA-N [Si].[Ni].[Cr].[Mo] Chemical compound [Si].[Ni].[Cr].[Mo] GEXAOYRHMSYOPM-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- -1 chromium silicon molybdenum nickel carbon nitrogen Chemical compound 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
Definitions
- duplex stainless steel having a good combination of [52] U S Cl 75/126 B 75/126 C 75/126 J hot workability, corrosion resistance and cold form- "75/128 A 75/128 N 75/128 ability, said duplex stainless steel consisting essentially [51] Int Cl 39/14 of, in weight percent, carbon 0.12 max., nitrogen 0.12 [58] Fie'ld C 128 A max., manganese 8 to 16, silicon 1.0 max., nickel 1.0 75/126 128 128 max., chromium 15 to 20, molybdenum 0.6 to 2.0, carbon nitrogen 0.06 to 0.14 and the balance iron, [56] References Cited the chromium equivalent of 13.5 to 16.0 in accor- UNITED STATES PATENTS dance with the formula:
- FIG. I is a graph showing the effect of carbon and nitrogen on the room-temperature tensile ductility
- FIG. 2 is a photograph showing the effect of various contents of carbon and nitrogen on the hot-workability of various alloy samples
- FIG. 3 is a graph showing the effect of manganese on the longitudinal tensile properties
- FIG. 4 represents anodic polarization curves for various steel compositions in a one normal sulfuric acid solution containing 0.5 moles of sodium chloride per liter;
- FIG. 5 is a photograph showing the pitting characteristics of various stainless steel samples with varying contents of molybdenum
- FIG. 6 comprises photographs of four stainless steel samples each with varying molybdenum contents witth respect to corrosion resistance
- FIG. 7 is a graph showing the relationship of austenite and ferrite content on the hot workability and cold workability, with chromium equivalent %Cr %Si %Mo 5Ni 30 (%C+%N).
- the hot workability of the alloy is dependent upon restricting the combined carbon plus nitrogen contents.
- the composition with respect to the austenite and ferrite promoting elements must be balanced to achieve a chromium equivalent wherein the alloy has substantially equal amounts of ferrite and austenite.
- Hot workability is promoted by the presence of ferrite.
- hot workability is impaired by the presence of austenite.
- Austenite however, promotes cold formability and thus must be present in the alloy for this purpose in combination with the ferrite necessary for hot workability to result in what is commonly termed a duplex alloy wherein the structure contains both austenite and ferrite.
- the alloy For purposes of corrosion resistance a minimum chromium content of 15 percent by weight is required.
- the alloy in combination with chromium, the alloy must contain molybdenum in an amount of at least 0.6 percent by weight; however, molybdenum must be restricted with regard to the maximum amount present as excessive amounts will have a detrimental effect on hot workability.
- Chromium Equivalent %Cr %Si %Mo %Ni 30 (%C+%N)
- the aboverecited composition limits may be modified to provide a silicon content of up to about 3 percent by weight.
- FIG. 1 of the drawings To show the effect of carbon and nitrogen on the cold formability of the steel reference should be made to FIG. 1 of the drawings.
- the designated alloys of TABLE 11 having varying carbon plus nitrogen contents were tested to determine roomtemperature tensile ductility as a measure of cold formability.
- the elongation values As may be seen from this FIGURE at carbon plus nitrogen contents of less than 0.06 percent elongation values, and thus cold formability, are poor; whereas, with increased carbon plus nitrogen content, and particularly carbon plus nitrogen contents of above about 0.08 percent, the elongation values drastically increase.
- cold formability continues to increase with carbon plus nitrogen contents above about 0.14 and 0.13 percent, at these high levels of carbon plus nitrogen the hot workability of the alloy is adversely affected. This is demonstrated by the photographs shown in FIG. 2.
- silicon and nickel are present only in normal residual amounts. However, silicon contents of up to about 3 percent may be desirable for elevated temperature applications requiring a high level of oxidation resistance.
- Molybdenum is critical from the standpoint of providing suitable corrosion resistance for motor vehicle applications. Specifically, for this purpose at least about 0.6 percent molybdenum, and preferably about 1.0 percent molybdenum, is needed in the steel of the invention to produce corrosion resistance comparable to that of A151 Type 434, which is a standard stainless steel grade having minimum acceptable resistance to the corrosive effects of road deicing salts that are the primary corrosive environment for stainless steels used in motor vehicle applications. As may be seen from FIG. 4 potentiodynamic polarization tests in chloridecontaining electrolyte indicate that about 0.90 percent molybdenum is required to produce pitting resistance comparable to Type 434. In the dip-dry tests, the results of which are shown in FIG.
- composition balance with respect to the ferrite formers and austenite formers is such that less than 30 percent ferrite is present, e.g., chromium equivalent of less than 13.5 percent, hot workability is poor and inadequate for satisfactory commercial production.
- composition balance is such that more than 65 percent ferrite is formed, e.g., chromium equivalent greater than 16.0 percent, the cold formability is decreased to a point where it is no longer superior to that of Type 434. From FIG. 7 it may be seen, therefore, that the various austenite and ferrite promoting elements in the composition must he carefully balanced to achieve the desired combination of hot workability and cold formability.
- manganese is an exception in that the manganese content between 8 and 16v percent has no significant effect on the structure of the stainless steel from the standpoint of the austenite and ferrite content. Manganese is important, however, as described above from the standpoint of its effect on room temperature ductility. Also, in maintaining a balance between the austenite and ferrite producing elements to achieve a chromium equivalent of 13.5 to 16 percent it is necessary that chromium be present in an amount of at least percent from the standpoint of corrosion resistance. Amounts of chromium in excess of percent, however, are not necessary for this purpose and merely unduly add to the cost of the alloy.
- a duplex stainless steel having good hot workability, cold formability and corrosion resistance consisting essentially of, in weight percent, carbon 0.12 max., nitrogen 0.12 max., manganese 8 to 16, silicon 3 max., nickel 1.0 max., chromium 15 to 20, molybdenum 0.6 to 2.0, carbon plus nitrogen 0.06 to 0.14 and balance iron, with a chromium equivalent of 13.5 to 16.0 in accordance with the formulae:
- the steel of claim 1 having up to 10 percent silicon.
- a duplex stainless steel having good hot workability, cold formability and corrosion resistance consisting essentially of, in weight percent, carbon 0.10 max., nitrogen 0.06 max., manganese 9 to 13, silicon 0.5 max., nickel 0.5 max., chromium 16 to 19, molybdenum 0.6 to 2.0, carbon plus nitrogen 0.08 to 0.13 and balance iron, with a chromium equivalent of 14.0 to 16.0 in accordance with the formulae:
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
Claims (2)
- 2. The steel of claim 1 having up to 10 percent silicon.
- 3. A duplex stainless steel having gooD hot workability, cold formability and corrosion resistance consisting essentially of, in weight percent, carbon 0.10 max., nitrogen 0.06 max., manganese 9 to 13, silicon 0.5 max., nickel 0.5 max., chromium 16 to 19, molybdenum 0.6 to 2.0, carbon plus nitrogen 0.08 to 0.13 and balance iron, with a chromium equivalent of 14.0 to 16.0 in accordance with the formulae: Chromium Equivalent, in percent % chromium + % silicon + % molybdenum - % nickel - 30 (% carbon + % nitrogen), to provide said steel with substantially equal amounts of ferrite and austenite after annealing within the range of 1,850* to 2,050*F, whereby a combination of both good hot workability and cold formability is achieved.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US389832A US3861908A (en) | 1973-08-20 | 1973-08-20 | Duplex stainless steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US389832A US3861908A (en) | 1973-08-20 | 1973-08-20 | Duplex stainless steel |
Publications (1)
Publication Number | Publication Date |
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US3861908A true US3861908A (en) | 1975-01-21 |
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Family Applications (1)
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US389832A Expired - Lifetime US3861908A (en) | 1973-08-20 | 1973-08-20 | Duplex stainless steel |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4047941A (en) * | 1974-09-23 | 1977-09-13 | Allegheny Ludlum Industries, Inc. | Duplex ferrit IC-martensitic stainless steel |
US4054448A (en) * | 1974-09-23 | 1977-10-18 | Allegheny Ludlum Industries, Inc. | Duplex ferritic-martensitic stainless steel |
US4828630A (en) * | 1988-02-04 | 1989-05-09 | Armco Advanced Materials Corporation | Duplex stainless steel with high manganese |
US20030086808A1 (en) * | 2001-09-02 | 2003-05-08 | Ann Sundstrom | Duplex stainless steel alloy |
EP1352982A2 (en) * | 2002-04-10 | 2003-10-15 | Thyssenkrupp Nirosta GmbH | Stainless steel, method for manufacturing of stress cracking free workpieces and product made thereof |
EP1715073A1 (en) * | 2004-01-29 | 2006-10-25 | JFE Steel Corporation | Austenitic-ferritic stainless steel |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2225440A (en) * | 1940-02-19 | 1940-12-17 | Electric Metallurg Company | Austenitic alloy steel |
US2357885A (en) * | 1943-12-08 | 1944-09-12 | Electro Metallurg Co | Melting magnesium |
US3112195A (en) * | 1959-06-04 | 1963-11-26 | Schoeller Bleckmann Stahlwerke | Drill stems for deep-well drill rods from non-magnetizable austenitic manganese-chromium alloy steels |
US3152934A (en) * | 1962-10-03 | 1964-10-13 | Allegheny Ludlum Steel | Process for treating austenite stainless steels |
US3736131A (en) * | 1970-12-23 | 1973-05-29 | Armco Steel Corp | Ferritic-austenitic stainless steel |
US3756807A (en) * | 1970-01-13 | 1973-09-04 | Nisshin Steel Co Ltd | Austenitic stainless steels |
-
1973
- 1973-08-20 US US389832A patent/US3861908A/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2225440A (en) * | 1940-02-19 | 1940-12-17 | Electric Metallurg Company | Austenitic alloy steel |
US2357885A (en) * | 1943-12-08 | 1944-09-12 | Electro Metallurg Co | Melting magnesium |
US3112195A (en) * | 1959-06-04 | 1963-11-26 | Schoeller Bleckmann Stahlwerke | Drill stems for deep-well drill rods from non-magnetizable austenitic manganese-chromium alloy steels |
US3152934A (en) * | 1962-10-03 | 1964-10-13 | Allegheny Ludlum Steel | Process for treating austenite stainless steels |
US3756807A (en) * | 1970-01-13 | 1973-09-04 | Nisshin Steel Co Ltd | Austenitic stainless steels |
US3736131A (en) * | 1970-12-23 | 1973-05-29 | Armco Steel Corp | Ferritic-austenitic stainless steel |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4047941A (en) * | 1974-09-23 | 1977-09-13 | Allegheny Ludlum Industries, Inc. | Duplex ferrit IC-martensitic stainless steel |
US4054448A (en) * | 1974-09-23 | 1977-10-18 | Allegheny Ludlum Industries, Inc. | Duplex ferritic-martensitic stainless steel |
US4828630A (en) * | 1988-02-04 | 1989-05-09 | Armco Advanced Materials Corporation | Duplex stainless steel with high manganese |
US20030086808A1 (en) * | 2001-09-02 | 2003-05-08 | Ann Sundstrom | Duplex stainless steel alloy |
EP1352982A2 (en) * | 2002-04-10 | 2003-10-15 | Thyssenkrupp Nirosta GmbH | Stainless steel, method for manufacturing of stress cracking free workpieces and product made thereof |
EP1352982A3 (en) * | 2002-04-10 | 2004-01-07 | Thyssenkrupp Nirosta GmbH | Stainless steel, method for manufacturing of stress cracking free workpieces and product made thereof |
EP1715073A1 (en) * | 2004-01-29 | 2006-10-25 | JFE Steel Corporation | Austenitic-ferritic stainless steel |
US20070163679A1 (en) * | 2004-01-29 | 2007-07-19 | Jfe Steel Corporation | Austenitic-ferritic stainless steel |
EP1715073A4 (en) * | 2004-01-29 | 2007-09-26 | Jfe Steel Corp | Austenitic-ferritic stainless steel |
EP2562285A1 (en) * | 2004-01-29 | 2013-02-27 | JFE Steel Corporation | Austenitic-ferritic stainless steel |
US8562758B2 (en) | 2004-01-29 | 2013-10-22 | Jfe Steel Corporation | Austenitic-ferritic stainless steel |
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Owner name: COLT INDUSTRIES OPERATING CORP. Free format text: MERGER AND CHANGE OF NAME;ASSIGNOR:CRUCIBLE CENTER COMPANY (INTO) CRUCIBLE INC. (CHANGED TO);REEL/FRAME:004120/0308 Effective date: 19821214 |
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Owner name: CRUCIBLE MATERIALS CORPORATION, A DE CORP. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:COLT INDUSTRIES OPERATING CORP.;REEL/FRAME:004194/0621 Effective date: 19831025 Owner name: CRUCIBLE MATERIALS CORPORATION, PENNSYLVANIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:COLT INDUSTRIES OPERATING CORP.;REEL/FRAME:004194/0621 Effective date: 19831025 |
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Owner name: MELLON BANK, N.A. FOR THE CHASE MANHATTAN BANK (NA Free format text: SECURITY INTEREST;ASSIGNOR:CRUCIBLE MATERIALS CORPORATION, A CORP. OF DE.;REEL/FRAME:004490/0452 Effective date: 19851219 Owner name: CHASE MANHATTAN BANK, THE (NATIONAL ASSOCIATION) A Free format text: SECURITY INTEREST;ASSIGNOR:CRUCIBLE MATERIALS CORPORATION, A CORP. OF DE.;REEL/FRAME:004490/0452 Effective date: 19851219 Owner name: MELLON BANK, N.A. AS AGENT FOR MELLON BANK N.A. & Free format text: SECURITY INTEREST;ASSIGNOR:CRUCIBLE MATERIALS CORPORATION, A CORP. OF DE.;REEL/FRAME:004490/0410 Effective date: 19851219 Owner name: MELLON FINANCIAL SERVICES CORPORATION Free format text: SECURITY INTEREST;ASSIGNOR:CRUCIBLE MATERIALS CORPORATION, A CORP. OF DE.;REEL/FRAME:004490/0410 Effective date: 19851219 |