USRE26225E - Heat-resistant high-strength stainless steel - Google Patents
Heat-resistant high-strength stainless steel Download PDFInfo
- Publication number
- USRE26225E USRE26225E US26225DE USRE26225E US RE26225 E USRE26225 E US RE26225E US 26225D E US26225D E US 26225DE US RE26225 E USRE26225 E US RE26225E
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- steels
- steel
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- cobalt
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- 229910001220 stainless steel Inorganic materials 0.000 title description 18
- 239000010935 stainless steel Substances 0.000 title description 14
- 229910000831 Steel Inorganic materials 0.000 description 117
- 239000010959 steel Substances 0.000 description 115
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 39
- 229910052803 cobalt Inorganic materials 0.000 description 25
- 239000010941 cobalt Substances 0.000 description 25
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 23
- 229910000529 magnetic ferrite Inorganic materials 0.000 description 21
- 229910000859 α-Fe Inorganic materials 0.000 description 21
- 229910052757 nitrogen Inorganic materials 0.000 description 20
- ZOKXTWBITQBERF-UHFFFAOYSA-N molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 19
- 239000011651 chromium Substances 0.000 description 18
- 229910052750 molybdenum Inorganic materials 0.000 description 18
- 239000011733 molybdenum Substances 0.000 description 18
- 229910052804 chromium Inorganic materials 0.000 description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 16
- 229910052799 carbon Inorganic materials 0.000 description 16
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 16
- VYZAMTAEIAYCRO-UHFFFAOYSA-N chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 15
- 239000000203 mixture Substances 0.000 description 14
- 238000005260 corrosion Methods 0.000 description 12
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 11
- 229910052721 tungsten Inorganic materials 0.000 description 11
- 239000010937 tungsten Substances 0.000 description 11
- 229910052720 vanadium Inorganic materials 0.000 description 11
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium(0) Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 10
- 238000007254 oxidation reaction Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 8
- 229910052759 nickel Inorganic materials 0.000 description 8
- 229910001566 austenite Inorganic materials 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 230000001747 exhibiting Effects 0.000 description 6
- 238000003379 elimination reaction Methods 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000005755 formation reaction Methods 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 238000005275 alloying Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000002035 prolonged Effects 0.000 description 2
- 230000000717 retained Effects 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 230000004584 weight gain Effects 0.000 description 2
- 235000019786 weight gain Nutrition 0.000 description 2
- OXBLHERUFWYNTN-UHFFFAOYSA-M Copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 description 1
- 229910001208 Crucible steel Inorganic materials 0.000 description 1
- 229910001315 Tool steel Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000003750 conditioning Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000009114 investigational therapy Methods 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000036961 partial Effects 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000002829 reduced Effects 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000003068 static Effects 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 230000001131 transforming Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- C22C38/30—Ferrous alloys, e.g. steel alloys containing chromium with cobalt
Definitions
- This invention pertains to stainless steel and particularly to stainless steel exhibiting very high strength at room and elevated temperatures. More particularly, the invention pertains to stainless steel having very high strength and exhibiting good oxidation and corrosion resistance under substantially atmospheric conditions at both ambient and elevated temperatures.
- austenitic stainless steels may be characterized as resistant to corrosion and oxidation and as having good strength at elevated temperatures.
- a disadvantage of such steels is their relatively low strength at ambient and moderately elevated temperatures.
- some steels of a heat-treatable nature and having a martensitic structure attain desired high strengths at ambient temperature which are retained at elevated temperatures.
- Exemplary of such steels are those covered by US. Patent No. 2,986,463, issued May 30, 1961, which was copending herewith. These steels, however are not characterized by good resistance to corrosion and oxidation.
- martensitic steels having chromium contents of about 12% by weight have improved corrosion and oxidation resistance while similarly exhibiting relatively good strength at low temperatures and fairly high strength at elevated temperatures.
- the latter martensitic steels however, are limited in chromium content to a maximum value of about 12%.
- the microstructure of the steel is characterized by the presence of substantial amounts of free ferrite. Free ferrite in substantial amounts is undesirable, being generally regarded as the probable cause of many hot-working difficulties as well as excessive variations in product properties with regard to the direction of working.
- steels which are heat-treatable to very high strength levels and which retain an unusually high percentage of such strength at temperatures up to 1200 F. or higher. These steels offer particularly high strengths, in both showtime and prolonged exposures, at temperatures ranging from about 1000 to 1200 F. and in addition exhibit high resistance to corrosion and oxidation.
- the inventive steels constitute a substantial improvement over the elevated-temperature structural materials known to the art and are particularly well suited for construction of aircraft and engine parts subjected to wide variations in operating temperatures.
- the steels of the invention comprise iron-base alloys of the following broad composition ranges:
- composition ranges of the inventive steels are as follows:
- the steels may contain impurities commonly encountered in the steelmaking practice (such as sulfur and phosphorus) and tramp elements.
- the steels of this invention are typified by Steels 77 and 107, the chemical compositions of which, together with those of a sizeable number of steels of similar compositions are given in Tables LA and I-B.
- Table I-A lists these steels according to significant compositional variable, whereas Table I-B lists the same steels according to identification number.
- Microstructural characteristics of the steels are determined by microstructural examination and mechanical properties of the steels as determined by hardness, tension, and creep-rupture tests are set forth in Tables Il through VI.
- FIG. 1 shows the effect of molybdenum on tensile properties and hardness
- FIG. 2 shows the efi'ect of molybdenum on creep-rupture strength
- FIG. 3 shows the eiTect of cobalt on tensile properties, hardness and microstructure
- FIG. 4 shows the eifect of cobalt on creep-rupture strength
- FIG. 5 shows the effect of vanadium on creep-rupture strength
- FIG. 6 shows the creep-rupture strength of various prior-art steels together with that of a steel typical of the invention
- FIG. 7 shows the tensile strength of various prior-art steels together with that of a steel typical of the invention
- FIG. 8 shows the oxidation resistance of various priorart steels together with that of a steel typical of the invention.
- steels within the invention are capable of exhibiting hardness of Rockwell C 48 or greater and tensile strength of 250,000 p.s.i. or greater at room temperature, tensile strength of 170,000 p.s.i. or greater at a temperature of 1100 F., creep-rupture life of 100 hours or more for an applied stress of 75,000 p.s.i. at a tempcrturc of 1100 F., and creep-rupture life of 50 hours or more for an applied stress of 35,000 psi. at a temperature of 1200" F.
- the steels of the invention exhibit good ductility at both room and elevated temperatures and have excellent weldability.
- Such heat treatment may involve the steps of austenitizing at an elevated temperature, preferably in the range of 1900 to 2100 F., cooling to room temperature, and heating at an elevated temperature below about 1500 F.
- Refrigeration at a subzero temperature, e.g. l F. is preferably included in the heat-treating schedule immediately following the austenitizing step for the purpose of facilitating the transformation of austenite.
- the chromium content of such steel should be about 12% or more.
- the higher the chromium content of the steel the higher its corrosion and oxidation resistance.
- chromium has been included as an essential element in the steels of the invention, the minimum content thereof being set at 11%.
- the maximum chromium content of the inventive steels has been set at about 16%.
- Molybdenum has been included in the steels of the invention as an effective strengthener. Supporting data therefor were obtained by testing steels of the basic inventive composition wherein the molybdenum content was varied (see Table IA, Steels 102, 103, 77 and 104). As shown in FIGS. 1 and 2, all the important strength properties, i.e., yield and tensile strengths at room temperature and at 1100 F., hardness after tempering at 1100 F. and 1200 F., and rupture times in creep-rupture tests at 1100 F. and 1200 F., are steadily enhanced as the molybdenum content is increased from about 0.1 to about 5%.
- Tables III through VI indicate that for this same molybdenum range, ductility is maintained at a high level. Molybdenum contents in excess of about 5% have some additional strengthening effects in short-time tests; however, the tendency for formation of free ferrite at high temperatures is increased. Therefore, although molybdenum contents up to about are included within the broad scope of the invention, a molybdenum content of about 4 to 6% is preferred for an optimum combination of properties. In addition to its strengthening role, molybdenum functions to increase significantly the corrosion resistance of the inventive steels in such media as chloride solutions.
- Tungsten is also an effective elevated-temperature strengthener in the inventive steels.
- a steel containing 5.11% tungsten and only 0.04% molybdenum 8 (Steel 122) exhibited a higher creep-rupture life (782 hours) than any other stecl when tested at 1100" F. under a stress of 75,000 psi. (see Table V).
- this same steel again exhibited a higher creeprupture life (175 hours) than any other steel tested (see Table VI).
- test data show that a combination of these elements is an effective strengthening agent in the inventive steels.
- Steel 75 containing 3.01% molybdenum and 2.35% tungsten, exhibited a creep-rupture life of 365 hours when tested at 1100 F. under a stress of 75,000 psi. (see Table V).
- Cobalt has been incorporated as an essential ingredient in the inventive steels for the purpose of obtaining desired microstructural characteristics, a critical cobalt range of 10 to 20% having been determined therefor.
- Table II strikingly reveals that cobalt values below about 10% (Steels 111, 112 and 113) result in the formation of excessive amounts of free ferrite, and that cobalt values above about 10% (Steels 76, 106, 77, 78 and 67) permit the complete or substantial elimination of free ferrite by proper compositional balance and/or heat-treatment selection.
- cobalt contents in excess of about 15% permit the retention of increasing amounts of austenite, the effect of which is to lower the room-temperature strength properties of the steels to some extent.
- the invention contemplates as a preferred embodiment a proper balancing of the cobalt content within said range with the nitrogen content.
- This proper balancing involves the restriction of the cobalt content to values in excess of 12% where the steel is essentially nitrogen-free or low in nitrogen, i.e., less than about 0.1%. Where the nitrogen present amounts to about 0.10% or greater, the cobalt content may be lowered to the range 10 to 12%. It will be noted from Table II after an austenitizing treatment at 1900 F.
- Steel 76 embraced within the broad concept of the invention, exhibits 5% free ferrite and that Steels 106, 77, 78 and 67, comprising preferred embodiments of the invention, exhibit not more than 1% free ferrite after the same austenitizing treatment.
- the alloying elements cobalt and nickel are interchangeable to some extent for the formation of an austenitic structure and for the elimination of free ferrite in steel.
- nickel up to 10.14% (Steel 118, and 114) were used in the steels of this invention as a replacement for cobalt, it became evident that While nickel effectively caused the amount of free ferrite to decrease, it also stabilized the austenitic structure of the steel so that when the free ferrite was fully eliminated (as in Steel 114 containing 10.14% nickel), the steel was not hardenable and thus incapable of exhibiting very high strengths at ambient and moderately elevated temperatures. Therefore, it is recognized that although to some extent nickel may be substituted for cobalt in these steels, no complete or substantial replacement of cobalt with nickel is possible.
- one-half percent each of vanadium were heat-treatable to no less than 20% and 30% free ferrite, respectively.
- high carbon plus nitrogen contents have an adverse effect on ductility at high strength levels and promote the retention of austenite in the microstructure. Therefore, to ensure proper compositional balance, it is preferred in the steels of this invention to keep the carbon plus nitrogen content between about 0.10% and 0.20% when the content of cobalt (as indicated heretofore, also a strong austenite former) is about 12% or higher, and between about 0.20% to 0.30% when the content of cobalt is below about 12%.
- Vanadium in amounts up to about 1.0% may be added to the steels of this invention to improve certain properties. As shown in FIG. 5, additions of vanadium to the steels of the invention increased rupture life at 1100 F., as determined by creep-rupture tests, the highest rupture life being obtained with a steel containing about 0.5% vanadium.
- FIGS. 6 and 7 Graphical depiction of the foregoing data is shown in FIGS. 6 and 7, wherein the superiority of the steels of the invention over the comparison steels of the prior art is clearly evident.
- Element Percent Carbon+nitrogen 0.06 to 0.35. Chromium From 11 to 16. Molybdenum-l- /z tungsten From 3 to less than 7. Nickel Up to 3. Vandium Up to 1. Nickel+cobalt 10 to 20. Manganese Up to 1. Silicon Up to 1. Aluminum Up to 0.25. Boron Up to 0.025. Iron Balance.
- vanadium is present on the low side of its range when the sum of carbon+nitrogen is on the [high] low side of the combined range of those elements.
- a stainless steel having enhanced strength and usewhere the sum of carbons-nitrogen is in the range of 0.10 to 0.20 when the sum of nickel-l-cobalt is at Least 12% and is in the range of 0.20 to 0.30 when the sum of nickel-l-cobalt is less than 12%.
- Element Percent Carbon 0.01 to 0.25. Nitrogen Less than 0.15. Carbon+nitrogen 0.06 to 0.35. Chromium 12 to 15.5. Molybdenum-P/z tungsten 4to 6. Cobalt 12 to 14. Vanadium Up to 0.5. Manganese Up to 0.4. Silicon Up to 0.4. Aluminum Up to 0.25. Boron Up to 0.025. Iron Balance.
- a heat-treated stainless steel consisting essentially of the composition of claim 1, said steel being characterized by the following minimum mechanical properties:
- a heat-treated stainless steel consisting essentially of the composition of claim 2, said steel being characterized by the following minimum mechanical properties:
- a heat-treated stainless steel consisting essentially of the composition of claim 3, said steel being characterized by the following minimum mechanical properties:
- Creep-rupture life (75,000 p.s.i. at 1100 F.) 100 Creep-rupture life (35,000 p.s.i. at 1200 F.) 50
- Creep-rupture life (75,000 psi. at 1100 F.) 100 Creep-rupture life (35,000 p.s.i. at 1200 F.) 50
- Creep-rupture life (75,000 p.s.i. at 1100 F.) 100 Creep-rupture life (35,000 p.s.i. at 1200 F.)
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
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Description
Publications (1)
Publication Number | Publication Date |
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USRE26225E true USRE26225E (en) | 1967-06-20 |
Family
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Family Applications (1)
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US26225D Expired USRE26225E (en) | Heat-resistant high-strength stainless steel |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0498105A1 (en) * | 1990-05-28 | 1992-08-12 | Hitachi Metals, Ltd. | High strength and high toughness stainless steel and method of manufacturing the same |
US5288347A (en) * | 1990-05-28 | 1994-02-22 | Hitachi Metals, Ltd. | Method of manufacturing high strength and high toughness stainless steel |
US7967927B2 (en) | 2001-02-09 | 2011-06-28 | QuesTek Innovations, LLC | Nanocarbide precipitation strengthened ultrahigh-strength, corrosion resistant, structural steels |
-
0
- US US26225D patent/USRE26225E/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0498105A1 (en) * | 1990-05-28 | 1992-08-12 | Hitachi Metals, Ltd. | High strength and high toughness stainless steel and method of manufacturing the same |
US5288347A (en) * | 1990-05-28 | 1994-02-22 | Hitachi Metals, Ltd. | Method of manufacturing high strength and high toughness stainless steel |
US7967927B2 (en) | 2001-02-09 | 2011-06-28 | QuesTek Innovations, LLC | Nanocarbide precipitation strengthened ultrahigh-strength, corrosion resistant, structural steels |
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AS | Assignment |
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, PENNSYLVANIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:COLT INDUSTRIES OPERATING CORP.;REEL/FRAME:004194/0621 Effective date: 19831025 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 |