Classifications

• • 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
  • C22C19/07—Alloys based on nickel or cobalt based on cobalt

Definitions

• This invention relates to cobalt base alloys. More particularly, this invention relates to cabolt-chromiumtungsten-nickel alloys containing relatively small amounts of lanthanum and relatively large amounts of carbon which are characterized by improved wear resistance and oxidation resistance at high temperatures in addition to having excellent high temperature mechanical properties.
• cobalt base alloys have been used extensively in the past for high temperature applications and have been found to be generally satisfactory except that in some instances they have been lacking in oxidation resistance, when compared to nickel base alloys.
• Other loW carbon cobalt base alloys containing minor amounts of lanthanum as disclosed in US. Pat. 3,418,111 have been found to have highly improved oxidation resistance. It would represent an advance in the art if cobalt base alloys could be provided with superior wear resistance and oxidation resistance at high temperatures.
• a cobalt base alloy in accordance with the present invention is an alloy consisting essentially of about Percent Chromium 18-35 Tungsten 3-18 Iron Up to 10 Carbon 0.41.3 Nickel 1-30 Silicon 0.2-1.2 Lanthanum 0.02-.l2 Tantalum Up to 10 Cobalt Balance
• a preferred range of the alloy of the present invention A preferred range of the alloy of the present invention providing optimum stress rupture and tensile properties 111 addition to excellent wear resistance is as follows:
• other metals can be adventitiously present in the alloy of this invention in minor amounts.
• zirconium may be present in amounts up to about 2%; vanadium up to about 2%; boron up to about 0.02%; manganese up to about 2%; Ti+Al up to about 4%; Cb up to about 2%.
• the lanthanum is preferably added in essentially elemental form, and should, in any event, exceed the aggregate amount of other rare earth metals in the final alloy.
• the lanthanum addition can be made using any convenient technique such as mischmetal, elemental lanthanum or lanthanum containing alloys.
• Table I shows alloy compositions which have been prepared by being melted, cast into ingots of about 20-25 lbs., hot worked to sheet and annealed at 2100-2250 F. for 10-15 minutes and quenchedQLanthanum additions were made to portions of base melts as indicated.
• the wear on the'rotated sample was 17.3X10- inch We1ght loss 1 hours/year per 1000 feet of travel.
• the wear for alloy D under the Density area of sample 100 hours 5 same conditions was 28 X inch per 1000 feet of travel.
• alloys A and C which Cobalt Balance contain lathanum and have relatively high carbon contents and are within the scope of the present invention and have superior oxidation properties as compared to alloys B and D which do not contain lathanum.
• the alloy of this invention in addition to having improved oxidation resistance, are also characterized by excellent mechanical properties at high temperatures.
• the alloy corresponding to the composition of alloy A, in cast form, was found to have a stress rupture life at a stress of 13,000 p.s.i. at a temperature of 1800" F. of 202 hours and an elongation of about 14%.
• a cylindrical cast sample of alloy having a composition of alloy C was rotated against a flat stationary sample of the same composition at a bearing pressure of 100 psi. The samples were at a temperature of 1400 F. during the test. The rotation was continued for 8 hours to pro- 2.
• An alloy in accordance with claim 1 consisting essentially of about 3.
• An alloy in accordance with claim 1 consisting essentially of about Percent Chromium 18-24 Tungsten 6-8 Iron Up to 10 Carbon 0.4-0.7 Nickel 10-30 Silicon 0.2-l.2 Lanthanum 0.02-0.12 Tantalum Up to 10 Cobalt Balance References Cited UNITED STATES PATENTS 3,418,111 12/1968 Herchenroeder 171 RICHARD O. DEAN, Primary Examiner

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Materials For Medical Uses (AREA)
• Continuous Casting (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25391015

Family Applications (1)

Country Status (12)

Cited By (11)

Families Citing this family (2)

Family Cites Families (2)

• 1969
  • 1969-12-22 US US887376A patent/US3582320A/en not_active Expired - Lifetime
• 1970
  • 1970-12-14 CA CA100581A patent/CA928533A/en not_active Expired
  • 1970-12-17 BE BE760495A patent/BE760495A/xx unknown
  • 1970-12-18 BR BR224759/70A patent/BR7024759D0/pt unknown
  • 1970-12-18 LU LU62284D patent/LU62284A1/xx unknown
  • 1970-12-18 GB GB6027470A patent/GB1340058A/en not_active Expired
  • 1970-12-19 DE DE2062776A patent/DE2062776C3/de not_active Expired
  • 1970-12-21 AT AT1148070A patent/AT306390B/de not_active IP Right Cessation
  • 1970-12-21 FR FR7046055A patent/FR2074104A5/fr not_active Expired
  • 1970-12-22 JP JP11657170A patent/JPS5416924B1/ja active Pending
  • 1970-12-22 SE SE17423/70A patent/SE353351B/xx unknown
  • 1970-12-22 NL NL7018666A patent/NL7018666A/xx unknown

Also Published As

Similar Documents

Legal Events