US3201232A - Use of steel involving prolonged stressing at elevated temperatures - Google Patents

Use of steel involving prolonged stressing at elevated temperatures Download PDF

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Publication number
US3201232A
US3201232A US183668A US18366862A US3201232A US 3201232 A US3201232 A US 3201232A US 183668 A US183668 A US 183668A US 18366862 A US18366862 A US 18366862A US 3201232 A US3201232 A US 3201232A
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steel
steels
molybdenum
less
alloy
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US183668A
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English (en)
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Hermann W R Thier
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Gebrueder Boehler and Co AG
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Gebrueder Boehler and Co AG
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    • 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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550°C
    • B23K35/3053—Fe as the principal constituent
    • B23K35/308—Fe as the principal constituent with Cr as next major constituent

Definitions

  • This invention relates to high-temperature steel having an optimum long-time creep resistance 031007000 and good working properties and more particularly to the use of steels containing 0.120.25% C, 75-85% Cr, l.52.5% M0, the balance being iron and the usual impurities including Si, Mn, S and P for applications in which said steel is stressed for long periods of time at temperatures exceeding 500 C., e.g. for superheaters of boilers.
  • the steels of this invention may contain in addition one or more of the following elements V, W, Ti, B, Cb, Ta, N and Co in amounts which singly or together do not exceed 3%.
  • Chrome-moly steels which have low chromium and low molybdenum contents. These include 13 CrMo 44 and 10 CrMo 910 steels according to the German Standard Specification DIN 17,175. The 13 CrMo 44 steel is used only up to 560 C. and the 10 CrMo 910 steel is used only up to 575 C. because the rapid decrease of the long-time strength at elevated temperatures and the insufiicient resistance to scaling of these steels precludes their economical use at higher temperatures.
  • Very high-temperature, austenitic steels having a much higher creep resistance are available for higher temperatures. These include the X 8 CrNiNb 1613 steel, Material No. 49 61 of the Stahleisenliste, and the X 8 CrNiMoVNb 1613 steel, Material No. 4988.
  • the very high'temperature, austenitic steels are much more expensive than the hightemperature chrome-moly steels having a low contents of alloying elements and have some properties which have adversely affected their use, e.g., in the construction of boilers, in Germany. They are highly susceptible to stress crack corrosion, and have a much higher coeflicient of thermal expansion than ferritic steels.
  • FIG. 1 of the drawings The long-time creep resistance values @3100010 of the two steel groups are plotted in FIG. 1 of the drawings, FIG. 2 is a similar graph relating to steels according to the invention.
  • compositions of the steels referred to in FIGURES 1 and 2 are shown in the following table:
  • the very high-temperature, austenitic steels are unecononiical particularly owing to their high price.
  • All these steels must be subjected to a solution treatment and then to precipitation hardening at elevated temperature, by which the alloying elements initially dissolved in the steel should be precipitated in the form of carbides, nitrides and other intermetallic mixed phases such as Fe T i so as to retard the slip and how processes taking place under tensile stress at elevated temperatures.
  • the longtime creep resistance of these steels decreases strongly with an increase in temperature and at 600 C. does not substantially exceed the long-time creep resistance of 10 CrMo 910 Steel. This is shown by the example of X 20 CrMoWV 121 Steel, Material No. 4935, in FIG. 1.
  • chrome-moly steels having medium chromium contents amounting to 7-9% Cr could hardly be used for applications requiring a prolonged stressing at elevated temperatures, e.g., in boilers.
  • the invention teaches that a pure chrome-moly steel having a medium chromium content of 79% Cr and a molybdenum content of 1.02.5% Mo exists, which has satisfactory heat-treating properties and an optimum long-time creep resistance for pure chrome-moly steels.
  • Molybdenum is known to have a strong tendency to form carbides and readily forms socalled special carbides. It is also known that molybdenum for-ms intermetallic compounds. Besides molybdenum increases the recrystallization temperature of iron by greatly impending the diffusion in the iron lattice. Owing to these properties the use of molybdenum in alloy steels improves the creep resistance.
  • the solubility, e.g., of molybdenum special carbides is much higher in the gamma solid solution than in the alpha solid solution.
  • the invention teaches to select a steel composition which can be fully austenitized.
  • the upper limits for the chromium and molybdenum contents of such steel are set by the complete transformation from alpha to gamma. Because chromium and molybdenum in these alloys highly restrict the range in which the homogenous gamma phase exists, excessive contents of these elements will prevent a complete austenitization, a complete solution of the carbide and a refinement of the grain.
  • the invention results in a particularly fine and uniform distribution of the segregations which increase the high-temperature strength when the transformation from gamma to alpha during the cooling from the solution treatment temperature is eliected as rapidly as possible or suddenly, as in the case of an eutectoid so that a pre-eutectoid segregation of coarse ferrite or coase carbides is avoided.
  • FIG. 2 shows also the creep resistance values of 10 CrMo 910 Steel, 8 CrMo 36 10 Steel, X 20 CrMoWV 121 Steel, X 8 CrNiNb 1613 Steel, X 8 CrNiMoVNb Steel 1613.
  • the creep strength investigation still in progress at the time of making the application indicate clearly that the steel according to the invention has a long-time creep resistance which is excellent for chromemoly steels.
  • the steel according to the present invention is nonscaling at temperatures up to and above 650 C. Owing to its high chromium content, its resistance to scaling is much higher than that of the low-alloy chrome-moly steels 13 CrMo 44 and 10 CrMo 910. Because V 0 melts at 665 C., vanadium-containing steels have in general a sufficient resistance to scaling only up to 600 C.
  • steel according to the invention has satisfactory casting, piercing, rolling and tube-forming properties.
  • the tubes may be hotand cold-worked. Due'to its simple composition, the making and working of the steel is very simple compared to complex alloy steels. Its economical use is also promoted by its relatively low price, which is due to the low contents of alloying constituents.
  • the welding properties can be improved by a reduction of the contents of Si, S, P of the steel according to this invention.
  • a steel alloy having a high creep resistance for very long time intervals up to 100,000 hours and good corrosion resistance in uses wherein said steel is stressed for prolonged periods of time at temperatures exceeding 500 C. consisting essentially of 0.12-0.25 carbon, 7.58.5% chromium, 1.52.5% molybdenum and up to 3% of an element selected from the group consisting of vanadium, tungsten, titanium, boron, columbium, tantalum, nitrogen, cobalt, and mixtures thereof, the balance being iron and the usual impurities including silicon, manganese, sulfur and phosphorus, there being less than 0.2% sulfur, less than 0.02% phosphorus and less than 0.3% silicon in said alloy.
  • a steel consisting essentially of 0.15 to 0.25% carbon, 7.5 to 8.5% chromium, 1.5 to 2.5% molybdenum, less than 0.30% silicon, less than 0.02% phosphorus and 0.02% sulphur, the remainder being iron, as a material of optimum value properties for long time use at temperature above 575 C. for superheaters of steam boilers.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Arc Welding In General (AREA)
US183668A 1961-04-01 1962-03-29 Use of steel involving prolonged stressing at elevated temperatures Expired - Lifetime US3201232A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DET19906A DE1166484B (de) 1961-04-01 1961-04-01 Warmfester Chrom-Molybdaen-Stahl mit optimalen Gebrauchseigenschaften fuer Langzeitbeanspruchung

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US (1) US3201232A (de)
AT (1) AT274028B (de)
CH (1) CH431103A (de)
DE (1) DE1166484B (de)
GB (1) GB995002A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3847600A (en) * 1969-08-27 1974-11-12 Nippon Kokan Kk High temperature alloy steel
US3855015A (en) * 1969-11-04 1974-12-17 Hitachi Ltd Work roll for hot rolling
US3954454A (en) * 1975-04-09 1976-05-04 Westinghouse Electric Corporation Temper embrittlement free low alloy steel
US4121930A (en) * 1975-12-29 1978-10-24 Kobe Steel, Ltd. Nitrogen containing high speed steel obtained by powder metallurgical process
US4533406A (en) * 1983-07-26 1985-08-06 The United States Of America As Represented By The United States Department Of Energy Minimum activation martensitic alloys for surface disposal after exposure to neutron flux
US20030226348A1 (en) * 2002-06-10 2003-12-11 Pelini Robert Gino System and method for producing injection-quality steam for combustion turbine power augmentation
US20070227154A1 (en) * 2003-06-09 2007-10-04 Pelini Robert G System and method for producing injection-quality steam for combustion turbine power augmentation

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5982189A (ja) * 1982-11-02 1984-05-12 Kobe Steel Ltd Ｃｒ−Ｍｏ系低合金鋼用潜弧溶液用溶接ワイヤ

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2123144A (en) * 1936-05-05 1938-07-05 Babcock & Wilcox Tube Company Apparatus for elevated temperature service
US2289449A (en) * 1941-04-16 1942-07-14 Bracburn Alloy Steel Corp Die steel for hot working
GB702555A (en) * 1951-05-18 1954-01-20 Charles Sykes Improvements in ferritic alloy steels
US2835571A (en) * 1957-07-02 1958-05-20 United States Steel Corp Steel for use at elevated temperature

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR768469A (fr) * 1934-02-10 1934-08-07 & Commerciale Des Aciers Soc I Alliages d'acier à grande résistance de durée à l'allongement

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2123144A (en) * 1936-05-05 1938-07-05 Babcock & Wilcox Tube Company Apparatus for elevated temperature service
US2289449A (en) * 1941-04-16 1942-07-14 Bracburn Alloy Steel Corp Die steel for hot working
GB702555A (en) * 1951-05-18 1954-01-20 Charles Sykes Improvements in ferritic alloy steels
US2835571A (en) * 1957-07-02 1958-05-20 United States Steel Corp Steel for use at elevated temperature

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3847600A (en) * 1969-08-27 1974-11-12 Nippon Kokan Kk High temperature alloy steel
US3855015A (en) * 1969-11-04 1974-12-17 Hitachi Ltd Work roll for hot rolling
US3954454A (en) * 1975-04-09 1976-05-04 Westinghouse Electric Corporation Temper embrittlement free low alloy steel
US4121930A (en) * 1975-12-29 1978-10-24 Kobe Steel, Ltd. Nitrogen containing high speed steel obtained by powder metallurgical process
US4533406A (en) * 1983-07-26 1985-08-06 The United States Of America As Represented By The United States Department Of Energy Minimum activation martensitic alloys for surface disposal after exposure to neutron flux
US20030226348A1 (en) * 2002-06-10 2003-12-11 Pelini Robert Gino System and method for producing injection-quality steam for combustion turbine power augmentation
US7146795B2 (en) * 2002-06-10 2006-12-12 Rgp Engineering Llc System and method for producing injection-quality steam for combustion turbine power augmentation
US20070227154A1 (en) * 2003-06-09 2007-10-04 Pelini Robert G System and method for producing injection-quality steam for combustion turbine power augmentation

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Publication number Publication date
AT274028B (de) 1969-09-10
CH431103A (de) 1967-02-28
GB995002A (en) 1965-06-10
DE1166484B (de) 1964-03-26

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