US3408179A - Corrosion-resistant nickel-chromium alloys with improved stress-rupture characteristics - Google Patents
Corrosion-resistant nickel-chromium alloys with improved stress-rupture characteristics Download PDFInfo
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- US3408179A US3408179A US479323A US47932365A US3408179A US 3408179 A US3408179 A US 3408179A US 479323 A US479323 A US 479323A US 47932365 A US47932365 A US 47932365A US 3408179 A US3408179 A US 3408179A
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- alloys
- stress
- corrosion
- rupture
- chromium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
- C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
- C22C19/053—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 30% but less than 40%
Definitions
- the present invention relates to nickel-chromium base alloys suitable for use under stress at elevated temperatures, and, more particularly, to high chromium, nickel alloys which manifest a combination of desired high temperature properties, including enhanced resistance to corrosive environments, such as the combustion products of impure fuel, and a satisfactory level of stress-rupture characteristics.
- nickelchromium base alloys have found wide and diverse utilization in industry, particularly for high temperature applications wherein substantial resistance to stress-rupture is required.
- Such alloys as commercially employed typically contain the precipitation hardening elements titanium and aluminum, and chromium in an amount of about to although a review of recent literature seemingly indicates a trend to using lesser amounts of chromium in certain nickel alloys to achieve a higher magnitude of stress-rupture characteristics. This accomplishment has usually been at the expense of resistance to corrosion.
- nickel alloys containing substantial amounts of chromium, to wit, 27% to are disclosed as having excellent resistance to corrosive environments. These alloys contained, in addition to chromium, about 1.5% to 2.5% titanium, about 0.5% to 1.1% aluminum, the combined amount of titanium plus aluminum being from 2% to 3.2%. It is also disclosed therein that while it might have been thought that higher amounts of titanium and aluminum would have resulted in a higher order of stressupture properties, the reverse was the case. In any event, these alloys manifested a stress-rupture life of the order of to 140 hours when tested under a stress of 17 long tons per square inch (t.p.s.i.) at 750 C. in the wrought condition upon age hardening.
- t.p.s.i. 17 long tons per square inch
- the nickel-chromium base alloys of the present invention contain (by weight) about 27% to about 35% chromium, about 1.5% to about 2.5% titanium, about 0.5% to about 1.1% and preferably from 0.5% to 0.85% aluminum, the total titanium plus aluminum being from 2% to 3.2% and preferably from 2.2% to about 2.75%, from about 0.01% to 0.1% carbon, from about 0.001% to 0.01% boron, from about 0.01% to 0.1% zirconium, from 12% to 30% cobalt, from 1% to 7% molybdenum and the balance essentially nickel.
- the alloys can be prepared by conventional processing techniques well known to those skilled in the art, although vacuum melting is preferred.
- the heat treatment of the alloys generally speaking, it comprises solution heating the alloys for about one to eight hours at a temperature within the range of 1050 C. to 1200 C., the alloys, upon cooling, being thereafter aged by heating for one to 24 hours within the temperature range of 600 C. to 800 C.
- a suitable heat treatment consists in solution heating for four hours at 1160 C. followed by air cooling and aging for 16 hours at 750 C. and again air cooling.
- Alloys Nos. 1 through 5 are outside the scope of the invention, Alloy No. 6 being within the invention.
- Each of the alloys was tested for stress-rupture characteristics by subjecting wrought specimens to a stress of 17 t.p.s.i. at 750 C., the alloys having been solution heated for four hours at 1160 C., air cooled, aged for sixteen hours at 700 C. and again air cooled.
- the life-to-rupture in hours and tensile elongation in per cent are also given in Table I:
- Alloys of the present invention are suitable for use about as rotor blades and other stressed parts of gas turbines.
- the alloys are particularly useful in forming articles subjected in use to high stress and corrosive atmospheres at elevated temperatures, for example, parts of furnaces and air heaters. Apart from being used in the Wrought 5 form, the alloys can also be used for cast components.
- a nickel-chromium-base alloy characterized by a high degree of corrosion resistance and stress-rupture characteristics at elevated temperatures, said alloy consisting essentially of about 27% to 35% chromium, about 1.5% to about 2.5% titanium, about 0.5% to about 1.1% aluminum, the total titanium plus aluminum being from about 2.2% to 2.75%, carbon at least 0.01% to about 0.1% with the proviso that the aluminum content is at least about 0.7% when the carbon content is in the range of 0.01% to 0.06%, about 14% to about 20% cobalt,
- An alloy in accordance with claim 1 containing at least 0.7% aluminum, at least 0.06% carbon, .and at least 16% cobalt.
Description
United States Patent ABSTRACT OF THE DISCLOSURE A corrosion-resistant nickel-chromium-base alloy of high chromium content (27% to 35%) possessing good stress-rupture properties at elevated temperatures and containing controlled amounts of titanium, aluminum, cobalt, molybdenum, carbon, boron and zirconium.
The present invention relates to nickel-chromium base alloys suitable for use under stress at elevated temperatures, and, more particularly, to high chromium, nickel alloys which manifest a combination of desired high temperature properties, including enhanced resistance to corrosive environments, such as the combustion products of impure fuel, and a satisfactory level of stress-rupture characteristics.
As is well known to those skilled in the art, nickelchromium base alloys have found wide and diverse utilization in industry, particularly for high temperature applications wherein substantial resistance to stress-rupture is required. Such alloys as commercially employed typically contain the precipitation hardening elements titanium and aluminum, and chromium in an amount of about to although a review of recent literature seemingly indicates a trend to using lesser amounts of chromium in certain nickel alloys to achieve a higher magnitude of stress-rupture characteristics. This accomplishment has usually been at the expense of resistance to corrosion.
In our British Patent No. 959,509, nickel alloys containing substantial amounts of chromium, to wit, 27% to are disclosed as having excellent resistance to corrosive environments. These alloys contained, in addition to chromium, about 1.5% to 2.5% titanium, about 0.5% to 1.1% aluminum, the combined amount of titanium plus aluminum being from 2% to 3.2%. It is also disclosed therein that while it might have been thought that higher amounts of titanium and aluminum would have resulted in a higher order of stressupture properties, the reverse was the case. In any event, these alloys manifested a stress-rupture life of the order of to 140 hours when tested under a stress of 17 long tons per square inch (t.p.s.i.) at 750 C. in the wrought condition upon age hardening.
Now, notwithstanding the excellent resistance to corrosion afforded by the alloys described in the abovementioned British patent, for some purposes an improved level of stress-rupture properties is also required. It has now been discovered that marked improvement in the stress-rupture properties can be achieved without loss of corrosion resistance in such alloys through the incorporation of special amounts of both cobalt and molybdenum therein.
It is an object of the present invention to provide high chromium, nickel-base alloys which manifest excellent resistance to corrosive environments and which also exhibit a satisfactory level of high temperature stress-rupture properties.
Other objects and advantages will become apparent from the following description.
Generally speaking, the nickel-chromium base alloys of the present invention contain (by weight) about 27% to about 35% chromium, about 1.5% to about 2.5% titanium, about 0.5% to about 1.1% and preferably from 0.5% to 0.85% aluminum, the total titanium plus aluminum being from 2% to 3.2% and preferably from 2.2% to about 2.75%, from about 0.01% to 0.1% carbon, from about 0.001% to 0.01% boron, from about 0.01% to 0.1% zirconium, from 12% to 30% cobalt, from 1% to 7% molybdenum and the balance essentially nickel. The use of the expression balance or balance essentially in referring to the nickel content of the alloys, as will be understood by those skilled in the .art, does not exclude the presence of other elements commonly present as incidental elements, e.g., deoxidizing and cleansing elements, and impurities normally associated therewith in small amounts which do not adversely aifect the novel characteristics of the alloys. In this regard, silicon should not exceed about 1% and manganese and iron should not exceed 1% and 2%, respectively, the level of impurities otherwise being preferably kept as low as possible.
In carrying the invention into practice, the alloys can be prepared by conventional processing techniques well known to those skilled in the art, although vacuum melting is preferred. With regard to the heat treatment of the alloys, generally speaking, it comprises solution heating the alloys for about one to eight hours at a temperature within the range of 1050 C. to 1200 C., the alloys, upon cooling, being thereafter aged by heating for one to 24 hours within the temperature range of 600 C. to 800 C. A suitable heat treatment consists in solution heating for four hours at 1160 C. followed by air cooling and aging for 16 hours at 750 C. and again air cooling.
For the purpose of giving those skilled in the art a better appreciation and/ or understanding of the invention, the following illustrative data are given:
A series of alloys were prepared in wrought form, the compositions being given in Table 1. Alloys Nos. 1 through 5 are outside the scope of the invention, Alloy No. 6 being within the invention. Each of the alloys was tested for stress-rupture characteristics by subjecting wrought specimens to a stress of 17 t.p.s.i. at 750 C., the alloys having been solution heated for four hours at 1160 C., air cooled, aged for sixteen hours at 700 C. and again air cooled. The life-to-rupture in hours and tensile elongation in per cent are also given in Table I:
TABLE I Composition (percent by weight) Stress, Rupture Properties at 17 t.s.i./ 750 C.
Alloy No.
C Cr Ti Al Ti-l-Al 00 Mo Sr Zr 13 Hours El.
(percent) Stress, Rupture Properties at 17 t.s.i./750 C.
B Hours El.
(percent) our British Patent No. 959,509, that the contents of titanium and aluminum, both individually and combined, be within the ranges specified herein, since departure therefrom, at least in any appreciable degree, leads to a marked fall in the stress-rupture properties. This is clearly shown by the results in Table III which relate to alloys heat treated and tested in the same manner as the alloys of Tables I and II. Alloys Nos. 6, 11, and 15 in this table are in accordance with the invention, the others are 10 not. I
TABLE III Composition 1 (percent by weight) Cr Ti Al Ti+Al 00 Mo Zr The data of Table I clearly illustrate the beneficial effect in stress-rupture properties achieved with the co- Alloy No.
presence of cobalt and molybdenum. Alloy No. 3 which contained about 19% cobalt but which was molybdenumfree did not afford any appreciable increase in stressrupture life over those alloys devoid of cobalt. The same is true with regard to the cobalt-free but molybdenum containing Alloys Nos. 4 and 5. However, the co-presence of molybdenum and cobalt resulted in the marked increase of stress-rupture life, the increase being well over 150% of the stress-rupture lives of Alloys Nos. 1 and 2.
mmmmmmm mdmwwomomwwmm c m fir u cus r kpflwi u 0. 0602582 .L m d 6 C a O hwfl C .D. m 0 "02.3 003 0452 wmm. m ufimrm. m d m Ms W, 666 ePd m m .1 is r em a c nm num mwm mmwyamm m m m Um .w. 1 m-w wmm so m o 1.11 5514303 m M and tuy %%HN 7 r m 5 d a X5 6 L 9 3059673 UD UD 1 B E 0 1332211 O -1 m e75 m d tfi SO Sem ac %t (2 0 WUA w m ow wmwn a e .2... .1 cl t C e a 3422 afifiam nim w m 0 0 0 0000 e m chu n tmfi me v mfi hctn IS EO 1 hI a 34 33 56776 7 tn 0 S a h t 9 000 000000 :a V.O m Om S 6 Op Bm000 00 0 0000 mnwwh mP m w m. moMm 00 00 i ,te ana d .1 a 30% we ammmww amn waP T mu n a 0 aeraeaa h w I m dm w whmvm m wm 0000 e 5 u .1 W fi t e .1 S 7023022 Ed 9 e n e I t 0 S t e E W 0 888 030600 mw m m m m 1 .0 .660 umus. mhmmwwr y M at 1111111 m t7 E r 736791308 TCVM ew t. tP B b a um wuo tm wmma m wmmm o more 9 47 44 O Nm Rao 8 8 v m B mm m C 6908 O 55 t UL .1 ah em w m p M "111 1222233 ddvme mk m S d mnw h nmm l 565 u e 8 U m 99803515 D mhT.l f 1 A 2556 a nn m sw m numanmonm nmmmmmwm d dd n 1.0.06 524 535 e e I S 5588 n H e H e .m oodommm mm h fl P w emmmfim kwa mm m E swfim C 3023419 S m m S W u 0 m e hd m. 2112 4977143 A n. u. s B 0000m00 08 m e am r. 049 1.1.1.1292 m rnmt 6.60.60.06.06 mmu we rma ow 0 0.01 9 0 .0 mmoBro 566656767 tta.m u m.mofTmNc.m C 2323 m 5 0 & 0000000 0 5 O 5 783 00 00 000 00 0 0 0 2 3 4. 5 5 3 5333333 3 000 eg SS i ..d0 t emm mm 6 s fiaaaaaa .awmmmmmwwm a m Vi :r. h C 540 Y m m nmm .Ws 7 88 td CU.E3 1 v m S h 6 O 0%77 5 E C O 3 m u mo w M 4.47201 7 ma filw M a m 03.2% v. 1. wi m u A 0. edrcsno n b o 311 1 0 rd.md ,ob mbe Of E t C .8 1799 7 U 0 aba w h .l mum L m n 221111 m31m w w Lm a n 0 6 W B r 0 ut t w mV V O A W M 20843456 0mH my mm S 00 nh T 097653547 t% o m mbp W w1w .1 m m H De H lt O r n r 83. f e 2 u mwNqma m 55551 50 mmw m i ttb h P M 066658 59 nw k i hwfm om 00 m i vfmfc m rooodod wo t r ml w qwMw 1m W 75392206 N u ocfnutm w eNW 020095798 b m m m gt. H d et 22 a2 L1 LLL Rh Y w m mwo m n I 60234608 m% n mm w e 0 00LLL00 & es a a 3333333m2 t t 65.1 a SS 0 88 f um we c mmwmwn mm mwmm mm m 0% fw am 00 00 000 00 mmwu a mW w s s mwfi emmw mmo m .we w wm e an mflo flwm irman m??? .0 fi m a a N nm s u P fl bee HP y .e.bu 0 N 5. 0 d3 esmma o am e n .wvoymmmwammmpm Dhi. C 03 0 Toet e 10 m. e a d iu f t mgm tto 7 mbwum mmmabwvmfianma 1 Alloys contained less than 0.3% silicon.
Alloys of the present invention are suitable for use about as rotor blades and other stressed parts of gas turbines.
The alloys are particularly useful in forming articles subjected in use to high stress and corrosive atmospheres at elevated temperatures, for example, parts of furnaces and air heaters. Apart from being used in the Wrought 5 form, the alloys can also be used for cast components.
0.002% or 0.003% and up to about 0.006% boron 0.02% to 0.08% zirconium, with the balance being essentially nickel. Lower amounts of carbon, i.e., not more than 0.06%, can be suitably used particularly with aluminum contents of 0.7% to 1.1%.
It is important, as in the case of the alloys described in 7 Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications .and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
We claim:
1. A nickel-chromium-base alloy characterized by a high degree of corrosion resistance and stress-rupture characteristics at elevated temperatures, said alloy consisting essentially of about 27% to 35% chromium, about 1.5% to about 2.5% titanium, about 0.5% to about 1.1% aluminum, the total titanium plus aluminum being from about 2.2% to 2.75%, carbon at least 0.01% to about 0.1% with the proviso that the aluminum content is at least about 0.7% when the carbon content is in the range of 0.01% to 0.06%, about 14% to about 20% cobalt,
6 about 3% to 6% molybdenum, about 0.001% to 0.006% boron, about 0.02% to about 0.08% zirconium and the balance essentially nickel.
2. An alloy in accordance with claim 1 containing at least 0.7% aluminum, at least 0.06% carbon, .and at least 16% cobalt.
References Cited UNITED STATES PATENTS 3,177,075 4/1965 Richards et a1 75l71 3,207,599 9/1965 Franklin et al 75l7l 3,222,165 12/1965 Bird et a1 75171 FOREIGN PATENTS 959,509 6/ 1964 Great Britain.
RICHARD O. DEAN, Primary Examiner.
mg? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 108, 1Y9 Dated August '2', 1969 Inventor) HARRY LEWIS and RONALD ALFRED SMITH It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 4, line 8, for "15" first occurrence, read -l l--.
SIGNED AND SEALED DEC 2 1969 (SEAL) Attest:
Edward M. Fletcher, Ir. Atteating Officer R. m.
Oomissianar of Patents
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB33351/64A GB1040797A (en) | 1964-08-14 | 1964-08-14 | Improvements relating to nickel-chromium alloys |
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US3408179A true US3408179A (en) | 1968-10-29 |
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US479323A Expired - Lifetime US3408179A (en) | 1964-08-14 | 1965-08-12 | Corrosion-resistant nickel-chromium alloys with improved stress-rupture characteristics |
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GB (1) | GB1040797A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3617263A (en) * | 1968-06-11 | 1971-11-02 | Int Nickel Co | Corrosion-resistant nickel-chromium base alloy |
US3865581A (en) * | 1972-01-27 | 1975-02-11 | Nippon Steel Corp | Heat resistant alloy having excellent hot workabilities |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB959509A (en) * | 1962-03-29 | 1964-06-03 | Mond Nickel Co Ltd | Improvements relating to nickel-chromium alloys |
US3177075A (en) * | 1961-07-14 | 1965-04-06 | Int Nickel Co | Nickel-chromium sheet alloy |
US3207599A (en) * | 1960-03-15 | 1965-09-21 | Int Nickel Co | Nickel-chromium-cobalt alloys |
US3222165A (en) * | 1958-11-26 | 1965-12-07 | Rolls Royce | Nickel chromium base alloy products |
-
1964
- 1964-08-14 GB GB33351/64A patent/GB1040797A/en not_active Expired
-
1965
- 1965-08-12 US US479323A patent/US3408179A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3222165A (en) * | 1958-11-26 | 1965-12-07 | Rolls Royce | Nickel chromium base alloy products |
US3207599A (en) * | 1960-03-15 | 1965-09-21 | Int Nickel Co | Nickel-chromium-cobalt alloys |
US3177075A (en) * | 1961-07-14 | 1965-04-06 | Int Nickel Co | Nickel-chromium sheet alloy |
GB959509A (en) * | 1962-03-29 | 1964-06-03 | Mond Nickel Co Ltd | Improvements relating to nickel-chromium alloys |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3617263A (en) * | 1968-06-11 | 1971-11-02 | Int Nickel Co | Corrosion-resistant nickel-chromium base alloy |
US3865581A (en) * | 1972-01-27 | 1975-02-11 | Nippon Steel Corp | Heat resistant alloy having excellent hot workabilities |
Also Published As
Publication number | Publication date |
---|---|
GB1040797A (en) | 1966-09-01 |
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