Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
  • B22F3/1003—Use of special medium during sintering, e.g. sintering aid
  • B22F3/1007—Atmosphere

Definitions

• the application discloses a process for consolidation of metal particles at an elevated temperature within a bed of particulate material comprising a mixture of refractory material and a particulate getter material, selected from the group consisting of aluminum, titanium, and zirconium, for reacting with oxygen released from the refractory material during the heating period to prevent contamination of the consolidated product.
• This application relates to consolidation of metal particles by compression within a surrounding material.
• the invention is particularly useful in compression of powdered metals surrounded by a powdered or granular refractory material.
• Hailey patent discloses a process in which a mass of material to be consolidated is placed within a refractory container, heated, and compressed. It has been found advantageous to practice the invention of the Hailey patent by preliminarily consolidating metal particles, and then embedding them directly in a particulate refractory, such as an oxide of silicon, before heating and hot consolidation. In carrying out the process of the Hailey patent, it has been found that oxygen may react with the metal being consolidated especially at elevated temperatures which exist prior to the consolidation.
• Reaction of the oxygen and the metal particles causes an oxide to be formed resulting in surface scaling, oxide inclusions within the part, and possible loss of strength.
• heating may be carried out in a protective atmosphere, there is a continuing risk of oxidation so long as the metal particles are at an elevated temperature.
• particles of a highly active metal into the particulate refractory material.
• a metal selected from the group consisting of aluminum, titanium and zirconium.
• aluminum we find aluminum to be especially advantageous and presently prefer to use the same in the practice of the invention. If titanium particles are used, how ever, they effectively eliminate nitrogen from reacting with the metal being consolidated.
• the metallic material to be consolidated is preformed into the general configuration desired for the finished product.
• the metal particles may be held together by a preliminary compression step sufiicient to bind the particles together but less than the ultimate consolidation. Also the particles could be adhered by use of a binder or resin.
• the preshaped part is placed and embedded within a particulate refractory material such as silica.
• the silica may be confined within a steel container of light gauge to enable easy handling of the preshaped part and the surrounding silica.
• the part has been 3,741,756 Patented June 26, 1973 ICC placed in the silica, more silica is placed on top so that the preshaped part is entirely embedded in silica.
• the silica particles Prior to the time the silica is used to embed the pre shaped part, the silica particles are thoroughly mixed with aluminum powder to distribute the aluminum evenly throughout. Thus the preshaped metal part is effectively embedded in a mixture of silica particles and aluminum powder.
• the preshaped part, the refractory material and the steel container are heated in a furnace, preferably under a reducing atmosphere. After the entire mass has been suitably heated, it is subjected to hot con solidation by application of pressure in a press.
• Aluminum is highly reactive with oxygen.
• the aluminum particles distributed through the silica react with any oxygen which may be present and form an aluminum oxide in the silica bed.
• the oxygen is thereby stripped from the part being formed resulting in a consolidation part substantially free of oxide.
• the part is removed from the silica-aluminum-aluminum oxide particles in which it is embedded, and is handled in a convenient manner.
• Titanium has the advantage that it will also attract and strip nitrogen from the preconsolidated metal part in the event it is desried to have a nitrogen-free part.
• the improvement which comprises providing a bed of particulate material consisting of a mixture of particulate refractory material and at least one particulate additive as a getter selected from the group of aluminum, titanium and zirconium.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Powder Metallurgy (AREA)
• Compositions Of Oxide Ceramics (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
• Ceramic Products (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22712484

Family Applications (1)

Country Status (8)

Cited By (4)

Families Citing this family (1)

• 1971
  • 1971-10-27 US US00193162A patent/US3741756A/en not_active Expired - Lifetime
• 1972
  • 1972-05-08 DE DE19722222515 patent/DE2222515A1/de active Pending
  • 1972-06-15 BE BE784930A patent/BE784930A/xx unknown
  • 1972-06-17 IT IT50975/72A patent/IT958424B/it active
  • 1972-06-30 NL NL7209222A patent/NL7209222A/xx unknown
  • 1972-07-06 FR FR7224482A patent/FR2157783A1/fr not_active Withdrawn
  • 1972-07-11 ES ES404726A patent/ES404726A1/es not_active Expired
  • 1972-09-05 JP JP47088409A patent/JPS4850906A/ja active Pending

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