US20010001399A1 - Austenitic nickel-chromium steel alloys - Google Patents
Austenitic nickel-chromium steel alloys Download PDFInfo
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- US20010001399A1 US20010001399A1 US09/230,417 US23041799A US2001001399A1 US 20010001399 A1 US20010001399 A1 US 20010001399A1 US 23041799 A US23041799 A US 23041799A US 2001001399 A1 US2001001399 A1 US 2001001399A1
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- hafnium
- tantalum
- zirconium
- nickel
- chromium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C30/00—Alloys containing less than 50% by weight of each constituent
Definitions
- the invention relates to a heat and creep resistant austenitic nickel chromium alloy steel such as is used in the petrochemical industry.
- Such alloys require high strength, especially stress-rupture strength, and adequate toughness at the usual operating temperatures, as well as adequate resistance to corrosion.
- U.S. patent specification No. 4,077,801 discloses a molybdenum- and cobalt-free austenitic cast nickel chromium alloy steel with 0.25% to 0.8% carbon, up to 3.5% silicon, up to 3.0% manganese, 8 to 62% nickel, 12 to 32% chromium, up to 2% niobium, 0.05 to less than 1.0% titanium, 0.05 to 2% tungsten and up to 0.3% nitrogen, balance iron, with high stress rupture strength and ductility at high temperatures.
- This cast alloy has good weldability and is a suitable material for apparatus for hydrogen reforming.
- the object of the invention is therefore to provide a nickel chromium alloy steel which can also withstand higher operating temperatures while having adequate creep strength together with resistance to carburisation and oxidation.
- the achievement of this object is based on the concept of substantially improving the heat resistance of an austenitic nickel chromium alloy steel by means of cobalt and molybdenum together with certain intermetallic compounds.
- Cobalt improves the stability of the austenitic iron-nickel-chromium primary structure. This is the case particularly when the alloy contains ferrite-stabilising elements such as molybdenum for solid solution hardening.
- the invention consists in an austenitic alloy steel with 0.3 to 1.0% carbon, 0.2 to 2.5% silicon, up to 0.8% manganese, 30.0 to 48.0% nickel, 16.0 to 22.0% chromium, 0.5 to 18.0% cobalt, 1.5 to 4% molybdenum, 0.2 to 0.6% niobium, 0.1 to 0.5% titanium, 0.1 to 0.6% zirconium, 0.1 to 1.5% tantalum and 0.1 to 1.5% hafnium, the ratio of the contents of tantalum and hafnium to the zirconium content being more than 2.4%, and the total content of tantalum, hafnium and zirconium amounting to 1.2 to 3%.
- cobalt content is at least 10% the alloy steel contains more than 20% iron and when its cobalt content is less than 10% it contains more than 30% iron.
- the alloy has an austenitic iron-nickel-chromium or an austenitic iron-nickel-chromium-cobalt primary structure together with a high stress-rupture or creep strength and is resistant to both carburisation and oxidation. Nevertheless a further improvement in the stress-rupture strength is possible if at the expense of its essential constituents the alloy contains 1.5 to 2.5% aluminium and/or the contents of tantalum, hafnium and zirconium satisfy the following condition:
- a particularly satisfactory alloy is one with 0.42% carbon, 1.3% silicon, 0.40% manganese, 34.0% nickel, 19.0% chromium, 3.5% molybdenum, 0.40% niobium, 0.25% titanium, 0.30% zirconium, 0.15% tantalum and 0.80% hafnium, balance iron, or else one with 0.44% carbon, 1.2% silicon, 0.40% manganese, 33.0% nickel, 19.0% chromium, 3.0% molybdenum, 0.40% niobium, 0.20% titanium, 0.15% zirconium, 1.0% tantalum and 0.10% hafnium, balance iron.
- Molybdenum improves the stress-rupture strength at intermediate temperatures, while intermetallic carbide phases impart to the iron-nickel-chromium primary structure, which in itself is weak, a high strength at temperatures up to 0.9 times its absolute melting point.
- Hafnium, zirconium, titanium, tantalum and niobium form primary carbides of the MC type, while chromium, in the presence of molybdenum, forms carbides of the M 7 C 3 and M 27 C 6 types in the intra- and interdendritic regions.
- FIG. 1 shows graphically the variation of the time to rupture in stress rupture tests as a function of the total content of hafnium and tantalum in relation to the zirconium content at a temperature of 1100° C. and high stress
- FIG. 2 shows graphically the influence of the total content of tantalum and hafnium on the stress rupture life in relation to the zirconium content at a temperature of 1100° C. and an initial stress of 9.4 MPa
- FIG. 3 shows the increase in weight with time in a hydrogen/propylene atmosphere at 1000° C.
- FIG. 4 shows the oxidation resistance of the alloy steel as an increase in weight with time during annealing in air at a temperature of 1050° C.
- compositions of the alloys tested are given in the following Table I, which shows three conventional alloys 1, 2 and 3, comparative alloys 4 and 6 to 12, and alloys 5 and 13 to 17 in accordance with the invention.
- the balance of the alloy consists of iron.
- the alloys were melted in an intermediate frequency furnace and cast in precision casting moulds or using the centrifugal casting process.
- test pieces for the stress rupture tests were made either from the samples precision cast to near final size or by machining from the centrifugally cast pipes. Using these test pieces the stress rupture behaviour was determined in the as-cast state according to ASTM E 139. The results of tests at 1100° C. and two different stresses are collected in the following Table II.
- FIGS. 1 and 2 demonstrate the clear superiority of the alloys in accordance with the invention in respect of their stress rupture strength at elevated temperatures as a function of the total content of intermetallic phase forming alloys above a particular level of contents against the background of a particular chromium content, a particular minimum content of nickel, nickel and cobalt, and molybdenum.
- FIG. 3 shows the results of the measurements and shows parabolic reaction kinetics with the diffusion of carbon as the rate-determining step and a relatively narrow range of increase in weight, with the exception of alloy 17 with an weight increase which is smaller by a factor of almost 4 than in the case of the conventional alloy 2 and the comparative alloy 7.
- the results of the tests with alloys 4 and 6-12 are evidence of the ineffectiveness of the addition of primary carbide forming elements on the stress rupture properties.
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- Engineering & Computer Science (AREA)
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- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
Description
- The invention relates to a heat and creep resistant austenitic nickel chromium alloy steel such as is used in the petrochemical industry.
- Such alloys require high strength, especially stress-rupture strength, and adequate toughness at the usual operating temperatures, as well as adequate resistance to corrosion.
- U.S. patent specification No. 4,077,801 discloses a molybdenum- and cobalt-free austenitic cast nickel chromium alloy steel with 0.25% to 0.8% carbon, up to 3.5% silicon, up to 3.0% manganese, 8 to 62% nickel, 12 to 32% chromium, up to 2% niobium, 0.05 to less than 1.0% titanium, 0.05 to 2% tungsten and up to 0.3% nitrogen, balance iron, with high stress rupture strength and ductility at high temperatures. This cast alloy has good weldability and is a suitable material for apparatus for hydrogen reforming.
- However, problems arise in view of the increasing process temperatures and the resulting reduction in life due to the decreasing creep strength with increasing temperatures and the fall in resistance to carburisation and oxidation.
- The object of the invention is therefore to provide a nickel chromium alloy steel which can also withstand higher operating temperatures while having adequate creep strength together with resistance to carburisation and oxidation.
- The achievement of this object is based on the concept of substantially improving the heat resistance of an austenitic nickel chromium alloy steel by means of cobalt and molybdenum together with certain intermetallic compounds. Cobalt improves the stability of the austenitic iron-nickel-chromium primary structure. This is the case particularly when the alloy contains ferrite-stabilising elements such as molybdenum for solid solution hardening.
- In particular the invention consists in an austenitic alloy steel with 0.3 to 1.0% carbon, 0.2 to 2.5% silicon, up to 0.8% manganese, 30.0 to 48.0% nickel, 16.0 to 22.0% chromium, 0.5 to 18.0% cobalt, 1.5 to 4% molybdenum, 0.2 to 0.6% niobium, 0.1 to 0.5% titanium, 0.1 to 0.6% zirconium, 0.1 to 1.5% tantalum and 0.1 to 1.5% hafnium, the ratio of the contents of tantalum and hafnium to the zirconium content being more than 2.4%, and the total content of tantalum, hafnium and zirconium amounting to 1.2 to 3%. When its cobalt content is at least 10% the alloy steel contains more than 20% iron and when its cobalt content is less than 10% it contains more than 30% iron.
- The alloy has an austenitic iron-nickel-chromium or an austenitic iron-nickel-chromium-cobalt primary structure together with a high stress-rupture or creep strength and is resistant to both carburisation and oxidation. Nevertheless a further improvement in the stress-rupture strength is possible if at the expense of its essential constituents the alloy contains 1.5 to 2.5% aluminium and/or the contents of tantalum, hafnium and zirconium satisfy the following condition:
- [(% Ta)+(% Hf)]/(% Zr)=1.2 to 14
- A particularly satisfactory alloy is one with 0.42% carbon, 1.3% silicon, 0.40% manganese, 34.0% nickel, 19.0% chromium, 3.5% molybdenum, 0.40% niobium, 0.25% titanium, 0.30% zirconium, 0.15% tantalum and 0.80% hafnium, balance iron, or else one with 0.44% carbon, 1.2% silicon, 0.40% manganese, 33.0% nickel, 19.0% chromium, 3.0% molybdenum, 0.40% niobium, 0.20% titanium, 0.15% zirconium, 1.0% tantalum and 0.10% hafnium, balance iron.
- Molybdenum improves the stress-rupture strength at intermediate temperatures, while intermetallic carbide phases impart to the iron-nickel-chromium primary structure, which in itself is weak, a high strength at temperatures up to 0.9 times its absolute melting point. Hafnium, zirconium, titanium, tantalum and niobium form primary carbides of the MC type, while chromium, in the presence of molybdenum, forms carbides of the M7C3 and M27C6 types in the intra- and interdendritic regions.
- The invention will now be described in more detail, by way of example, with reference to some embodiments. In the drawings:
- FIG. 1 shows graphically the variation of the time to rupture in stress rupture tests as a function of the total content of hafnium and tantalum in relation to the zirconium content at a temperature of 1100° C. and high stress,
- FIG. 2 shows graphically the influence of the total content of tantalum and hafnium on the stress rupture life in relation to the zirconium content at a temperature of 1100° C. and an initial stress of 9.4 MPa,
- FIG. 3 shows the increase in weight with time in a hydrogen/propylene atmosphere at 1000° C., and
- FIG. 4 shows the oxidation resistance of the alloy steel as an increase in weight with time during annealing in air at a temperature of 1050° C.
- The compositions of the alloys tested are given in the following Table I, which shows three
conventional alloys comparative alloys alloys - The test pieces for the stress rupture tests were made either from the samples precision cast to near final size or by machining from the centrifugally cast pipes. Using these test pieces the stress rupture behaviour was determined in the as-cast state according to ASTM E 139. The results of tests at 1100° C. and two different stresses are collected in the following Table II.
- The data from the stress rupture tests, the minimum creep rate and the time of onset of tertiary creep make it clear that in view of their contents of strong carbide formers the alloys in accordance with the invention are markedly superior to the comparative alloys. Thus the diagrams of FIGS. 1 and 2 demonstrate the clear superiority of the alloys in accordance with the invention in respect of their stress rupture strength at elevated temperatures as a function of the total content of intermetallic phase forming alloys above a particular level of contents against the background of a particular chromium content, a particular minimum content of nickel, nickel and cobalt, and molybdenum. This shows that the improvement in the stress rupture strength and the creep properties is based on the one hand on the ratio of the total content of tantalum and hafnium to the zirconium content in accordance with the invention, and on the other hand on the influencing of the primary structure by chromium and/or nickel plus cobalt.
- To determine the carburisation resistance, samples were tested at 900° C. and at 1000° C. in an atmosphere of hydrogen and propylene in a volume ratio of 89:11, with a volume throughput of 601 mil/min. The amount of carbon pick-up was continuously measured using a microbalance.
- The diagram of FIG. 3 shows the results of the measurements and shows parabolic reaction kinetics with the diffusion of carbon as the rate-determining step and a relatively narrow range of increase in weight, with the exception of
alloy 17 with an weight increase which is smaller by a factor of almost 4 than in the case of theconventional alloy 2 and thecomparative alloy 7. The results of the tests withalloys 4 and 6-12 are evidence of the ineffectiveness of the addition of primary carbide forming elements on the stress rupture properties. - The results of gravimetric oxidation tests in air at 1050° C., with a test duration of 25 hours, are illustrated by the diagram of FIG. 4 with its likewise parabolic relationship, which makes clear the superior oxidation properties of the
test alloy 16 in accordance with the invention compared with theconventional test alloy 2.TABELLE 1 Alloy No. 1 2 3 4 5 6 7 8 Alloy ID 0.4867 0.4852 micro 6-4867 m 94008/901 94008/902 94008/903 94008/4.1 94008/4.2 Melt 94004-0 21/9082/0 AVA/B/C 347 248 351 356 357 Elements % Ni 33.96 23.46 21.00 34.03 23.73 37.86 31.18 31.22 Cr 24.00 24.25 23.06 10.04 10.110 23.29 23.17 23.31 Me .54 .02 .53 4.470 3.460 3.320 3.640 3.120 Br 1.320 1.880 1.700 1.309 1.780 1.480 1.780 1.370 O .48 .48 .49 .42 .415 .416 .436 .44 Mn .55 1.220 .41 .48 .40 .28 .37 .40 Nb .40 .78 .01 .43 .43 .38 .41 .41 Ti .01 .08 .19 .14 .18 .20 .26 .21 Ce .00 .00 .01 <.01 <.01 <.01 <.01 14.78 Al .01 <.02 .01 .024 .026 .030 .034 .027 Te .00 .00 .00 .18 .14 .78 .86 .78 Mi .00 .00 .00 .023 .78 .71 .97 .56 Zr .00 .01 .11 .105 .310 .185 .200 .177 I* .022 .017 .016 .013 .018 .020 .022 .020 B .001 .008 .001 <.005 <.005 <.005 <.005 <.005 Fe Bal. Bal. Bal. Bal. Bal. Bal. Bal. Bal. 9 10 11 12 13 14 15 16 17 34008/4.3 24008/4.31 54005/905 84008/906 64008/907 94008/908 84008/900 84008/8.1 84008/0.3 360 386 361 365 367 369 377 376 383 31.50 32.15 28.76 27.24 28.27 23.24 23.01 32.31 31.28 22.40 23.64 23.21 34.417 18.14 19.14 18.17 19.81 17.88 3.00 3.150 3.100 3.050 6.200 3.040 3.280 3.150 3.080 1.420 1.840 1.850 1.900 1.550 1.210 1.380 1.240 .08 .43 .45 .485 .415 .45 44 .400 .435 .420 .40 .27 .37 .87 .98 .37 .41 .40 .41 .27 .40 .35 .40 .35 .40 .37 .30 .30 .38 .19 .17 .18 .21 .17 .21 .21 .28 14.61 15.22 .51 .06 .32 .08 <.01 15.70 14.26 .048 .026 .025 .021 .026 .021 .028 .028 1.650 .71 1.030 .34 .22 .97 1.010 .70 .057 1.230 1.200 .57 .98 .13 .82 .12 .34 .68 1.260 .306 .263 .156 .136 .128 .134 .348 .392 .464 .018 .017 .018 .018 .017 .010 .012 .017 .013 <.006 <.006 <.006 <.006 <.008 <.005 <.006 <.006 <.006 Bal. Bal. Bal. Bal. Bal. Bal. Bal. Bal. Bal. -
TABELLE 2Testparameter 1100° C./9.4 MPa 1100° C./18 MPa Stress rupture life, Min. creep rate, Onset of tert. Stress rupture life, Min. creep rate, Onset of tert. Alloy No. Alloy ID Melt hr. %/hr. Creep, hr. hr. %/hr. Creep, hr. 1 G-4857 24004-0 — — — 90.5 2.34*c-2 42.1 2 G-4252 micro 21/3052/2 1258 3.61c-4 961.6 133.8 3.0*c-3 117.8 3 G-4867m AVA/B/C 1271 — 328.8 115.5 6.5*c-3 59.8 4 34008/301 347 384 — — 110.5 — — 5 34008/303 346 3470 1.23*c-4 2433.4 300.2 1.49*c-3 205.4 6 34008/303 351 183.5 — — 32.3 — — 7 34008/4.1 245 184 — — 30.60 — — 8 34006/4.2 357 313 — — 60.0 — — 9 34006/4.3 358 564 — — 79 — — 10 34006/4.31 345 384 — — 79.8 — — 11 34006/906 261 101.2 — — 19.50 — — 12 34006/505 363 148 — — 28 — — 13 34008/907 367 3497 — — 291.1 — — 14 84008/908 368 2878 — — 243.3 — — 15 84006/909 377 2067 — — 272.1 — — 16 84008/9.1 378 2815.7 1.88*c-4 864.1 452.5 2.43*c-3 201.9 17 84008/8.3 383 6703.8 1.12*c-4 5163.3 496.7 1.46*c-3 292.2
Claims (6)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19629977.2 | 1996-07-25 | ||
DE19629977 | 1996-07-25 | ||
DE19629977A DE19629977C2 (en) | 1996-07-25 | 1996-07-25 | Austenitic nickel-chrome steel alloy workpiece |
PCT/EP1997/003975 WO1998004757A1 (en) | 1996-07-25 | 1997-07-23 | Austenitic nickel-chromium steel alloys |
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US20010001399A1 true US20010001399A1 (en) | 2001-05-24 |
US6409847B2 US6409847B2 (en) | 2002-06-25 |
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US09/230,417 Expired - Fee Related US6409847B2 (en) | 1996-07-25 | 1997-07-23 | Austenitic nickel-chromium steel alloys |
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US (1) | US6409847B2 (en) |
EP (1) | EP0914485B1 (en) |
JP (1) | JP3710097B2 (en) |
CA (1) | CA2261736C (en) |
DE (2) | DE19629977C2 (en) |
WO (1) | WO1998004757A1 (en) |
Cited By (3)
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WO2004015029A1 (en) * | 2002-07-25 | 2004-02-19 | Schmidt + Clemens Gmbh + Co. Kg | Method and ribbed tube for thermally cleaving hydrocarbons |
US20050131263A1 (en) * | 2002-07-25 | 2005-06-16 | Schmidt + Clemens Gmbh + Co. Kg, | Process and finned tube for the thermal cracking of hydrocarbons |
EP1935996A1 (en) * | 2002-11-04 | 2008-06-25 | Paralloy Limited | High temperature resistant alloys |
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US20040156737A1 (en) * | 2003-02-06 | 2004-08-12 | Rakowski James M. | Austenitic stainless steels including molybdenum |
GB2394959A (en) * | 2002-11-04 | 2004-05-12 | Doncasters Ltd | Hafnium particle dispersion hardened nickel-chromium-iron alloys |
US7482502B2 (en) * | 2003-01-24 | 2009-01-27 | Stone & Webster Process Technology, Inc. | Process for cracking hydrocarbons using improved furnace reactor tubes |
SE527319C2 (en) | 2003-10-02 | 2006-02-07 | Sandvik Intellectual Property | Alloy for high temperature use |
US7985304B2 (en) * | 2007-04-19 | 2011-07-26 | Ati Properties, Inc. | Nickel-base alloys and articles made therefrom |
CN101592186B (en) * | 2009-07-10 | 2011-01-26 | 攀钢集团钢铁钒钛股份有限公司 | Axle bush and sleeve |
CN101592187B (en) * | 2009-07-10 | 2011-04-13 | 攀钢集团钢铁钒钛股份有限公司 | Axle bush and axle sleeve |
US9011620B2 (en) * | 2009-09-11 | 2015-04-21 | Technip Process Technology, Inc. | Double transition joint for the joining of ceramics to metals |
UA111115C2 (en) | 2012-04-02 | 2016-03-25 | Ейкей Стіл Пропертіс, Інк. | cost effective ferritic stainless steel |
EP3233269B1 (en) | 2014-12-16 | 2022-08-10 | ExxonMobil Chemical Patents Inc. | Heat transfer tube weldment suitable for use in pyrolysis furnace and pyrolysis process |
WO2016099738A1 (en) | 2014-12-16 | 2016-06-23 | Exxonmobil Research And Engineering Company | Alumina forming refinery process tubes with mixing element |
US9909395B2 (en) | 2015-09-21 | 2018-03-06 | National Oilwell DHT, L.P. | Wellsite hardfacing with distributed hard phase and method of using same |
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GB618560A (en) * | 1945-11-02 | 1949-02-23 | Kanthal Ab | Heat resistant machinable alloy with high strength while hot |
US3135602A (en) * | 1957-02-11 | 1964-06-02 | Babcock & Wilcox Co | 45% iron base austenitic cr-ni alloy with 18-22% cr, 27-32% ni or (ni+co) plus strengthening additions |
JPS58207352A (en) * | 1982-05-28 | 1983-12-02 | Mitsubishi Metal Corp | Cast ni alloy for guide shoe |
DE1233609B (en) * | 1961-01-24 | 1967-02-02 | Rolls Royce | Process for the heat treatment of a hardenable nickel-chromium alloy |
US3658516A (en) * | 1969-09-05 | 1972-04-25 | Hitachi Ltd | Austenitic cast steel of high strength and excellent ductility at high temperatures |
US3713788A (en) * | 1970-10-21 | 1973-01-30 | Chromalloy American Corp | Powder metallurgy sintered corrosion and heat-resistant, age hardenable nickel-chromium refractory carbide alloy |
US4077801A (en) | 1977-05-04 | 1978-03-07 | Abex Corporation | Iron-chromium-nickel heat resistant castings |
US4313760A (en) | 1979-05-29 | 1982-02-02 | Howmet Turbine Components Corporation | Superalloy coating composition |
US4764225A (en) * | 1979-05-29 | 1988-08-16 | Howmet Corporation | Alloys for high temperature applications |
US4302256A (en) * | 1979-11-16 | 1981-11-24 | Chromalloy American Corporation | Method of improving mechanical properties of alloy parts |
JPS5820732A (en) | 1981-07-24 | 1983-02-07 | Comput Basic Mach Technol Res Assoc | Preparation of magnetic thin film of oxide |
EP0246092A3 (en) * | 1986-05-15 | 1989-05-03 | Exxon Research And Engineering Company | Alloys resistant to stress corrosion cracking |
JPS63297542A (en) * | 1987-05-28 | 1988-12-05 | Nissan Motor Co Ltd | Heat resistant wear resistant iron based sintered alloy |
JPH072981B2 (en) | 1989-04-05 | 1995-01-18 | 株式会社クボタ | Heat resistant alloy |
JP2574528B2 (en) * | 1990-09-06 | 1997-01-22 | 財団法人電気磁気材料研究所 | High hardness low magnetic permeability non-magnetic functional alloy and method for producing the same |
JPH04116142A (en) * | 1990-09-06 | 1992-04-16 | Res Inst Electric Magnetic Alloys | Nonmagnetic functional alloy having high rigidity and low magnetic permeability and its manufacture |
US5310522A (en) | 1992-12-07 | 1994-05-10 | Carondelet Foundry Company | Heat and corrosion resistant iron-nickel-chromium alloy |
-
1996
- 1996-07-25 DE DE19629977A patent/DE19629977C2/en not_active Expired - Fee Related
-
1997
- 1997-07-23 CA CA002261736A patent/CA2261736C/en not_active Expired - Fee Related
- 1997-07-23 WO PCT/EP1997/003975 patent/WO1998004757A1/en active IP Right Grant
- 1997-07-23 US US09/230,417 patent/US6409847B2/en not_active Expired - Fee Related
- 1997-07-23 EP EP97937513A patent/EP0914485B1/en not_active Expired - Lifetime
- 1997-07-23 DE DE59707227T patent/DE59707227D1/en not_active Expired - Lifetime
- 1997-07-23 JP JP50847098A patent/JP3710097B2/en not_active Expired - Fee Related
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004015029A1 (en) * | 2002-07-25 | 2004-02-19 | Schmidt + Clemens Gmbh + Co. Kg | Method and ribbed tube for thermally cleaving hydrocarbons |
US20050131263A1 (en) * | 2002-07-25 | 2005-06-16 | Schmidt + Clemens Gmbh + Co. Kg, | Process and finned tube for the thermal cracking of hydrocarbons |
EA010936B1 (en) * | 2002-07-25 | 2008-12-30 | Шмидт+Клеменс Гмбх+Ко. Кг | Method and ribbed tube for thermally cleaving hydrocarbons |
US7963318B2 (en) | 2002-07-25 | 2011-06-21 | Schmidt + Clemens Gmbh + Co., Kg | Finned tube for the thermal cracking of hydrocarbons, and process for producing a finned tube |
EP1935996A1 (en) * | 2002-11-04 | 2008-06-25 | Paralloy Limited | High temperature resistant alloys |
Also Published As
Publication number | Publication date |
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US6409847B2 (en) | 2002-06-25 |
DE19629977A1 (en) | 1998-01-29 |
CA2261736C (en) | 2005-06-14 |
EP0914485A1 (en) | 1999-05-12 |
DE19629977C2 (en) | 2002-09-19 |
JP3710097B2 (en) | 2005-10-26 |
DE59707227D1 (en) | 2002-06-13 |
WO1998004757A1 (en) | 1998-02-05 |
EP0914485B1 (en) | 2002-05-08 |
JP2000513767A (en) | 2000-10-17 |
CA2261736A1 (en) | 1998-02-05 |
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