Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/05—Mixtures of metal powder with non-metallic powder
  • C22C1/059—Making alloys comprising less than 5% by weight of dispersed reinforcing phases
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/10—Alloys containing non-metals

Definitions

• the invention relates to a method for producing heat-treated profiles and moldings from oxide dispersion-hardened superalloys based on nickel with a rough structure formed from stem-shaped grains.
• the prefabricated parts consisting of profiles or moldings made of oxide dispersion-hardened superalloys based on nickel, are used due to their excellent mechanical-technological properties at comparatively high temperatures in thermal mechanical engineering, in particular as a material for the blades of the rotor of thermal turbomachines.
• alloy powders with a grain size of ⁇ 0.5 mm, preferably 10 to 500 ⁇ m are produced by mechanical alloying for the production of profiles and moldings from oxide dispersion-hardened nickel-based superalloys from powder mixtures containing the alloy components. generated, then compressed by extrusion or hot pressing, such as hot isostatic pressing, hot forging or the like, under vacuum or inert gas in appropriately designed molds and then subjected to a zone annealing process at temperatures of 1150 to 1350 ° C.
• the profiles or shaped bodies are guided in the forming direction at a speed of up to 240 mm / h through the induction coil of a heating device, the axial temperature / displacement gradient being 7 to 20 ° C / mm.
• This zone annealing creates a recrystallization front that is perpendicular to the axial temperature / path gradient, behind which there are longitudinal, coarse, stem-shaped grains in the longitudinal direction, in the longitudinal direction of which the profile or shaped body has the highest mechanical strength (EP-A-0 232 477).
• zone annealing process involves considerable effort for the heating device, since certain temperature ranges and temperature gradients have to be observed. Furthermore, the production of the profiles or shaped bodies with a coarse structure formed from stem-shaped grains takes place too slowly. In addition, zone annealing is only suitable for prismatic profiles.
• the solution to this problem is that the profiles or moldings of a 5 to 90 min preheat treatment at temperatures of 950 to 1180 ° C and then an isothermal heat treatment at temperatures of> 1180 to 1300 ° C for a period of 5 to 120 min be subjected.
• the recrystallization structure produced by this heat treatment according to the invention and consisting of stem-shaped grains is very similar to the stem-shaped recrystallization structure produced by zone annealing and has similar mechanical-technological properties.
• the preheating treatment lasts 10 to 60 minutes and is preferably carried out at temperatures from 1050 to 1170 ° C., in particular at temperatures from 1085 to 1140 ° C.
• the isothermal heat treatment lasts 30 to 60 minutes and is carried out at temperatures from 1190 to 1250 ° C.
• zone annealing can also be carried out.
• the zone annealing is carried out in such a way that the profile is moved through the heating zone at a speed of 200 to 2000 mm / h and is thereby heated to a temperature of 950 to 1150 ° C., the temperature / displacement gradient in the heating zone 1 is up to 20 ° C / mm.
• the longitudinal section shown in the drawing in a magnification of 5.3 times through the profile treated according to the invention shows that the fine-grained structure of the extruded molded body has been converted into a coarse structure with elongated grains.
• a 20 mm diameter rod made of the same nickel-based superalloy was moved through a heating zone at a constant feed rate of 950 mm / h, heated to a temperature of 1095 ° C and then subjected to an isothermal heat treatment at a temperature of 1200 ° C and 60 min duration.
• the fine-grained structure of the extruded round profile is converted into a uniform coarse structure with elongated grains.
• the elongated grains have an average length of 20 mm, a width of 0.5 mm and a thickness of 0.5 mm.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=25890088

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (5)

• 1990
  • 1990-11-28 DE DE4037827A patent/DE4037827A1/de not_active Withdrawn
• 1991
  • 1991-01-15 EP EP91200063A patent/EP0442545A1/fr not_active Withdrawn
  • 1991-02-14 JP JP3042661A patent/JPH055167A/ja active Pending

Patent Citations (5)

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