Back to results
US 4,129,443 AGranted
Method for improving the sinterability of iron powder derived from comminuted scrap metal
AssigneeFord Motor Company
InventorSydney M. Kaufman
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeFord Motor Company
InventorSydney M. Kaufman
Estimating the term…
Methods are disclosed for embrittling scrap metal for comminution and for subsequent or simultaneous treatment of the comminuted metal powder to improve sintering kinetics and prevent oxidation of alloying ingredients. A first embrittling method impacts the scrap metal at a temperature below its ductile-brittle transition temperature to cryogenically provide scrap metal powder. The scrap metal is subjected to two impacting operations (such as by use of a ball milling machine), the first operation being carried out simultaneously with the cryogenic medium and the second impacting operation is carried out at ambient temperature conditions utilizing milling elements which impart cold work to at least a portion of the cryogenic powder. An anti-oxidation agent, such as copper or iron, is mechanically transferred to substantially each particle of said cryogenic powder during the second operation to form a continuous copper or iron envelope thereabout. The coated cryogenic powder is then compacted and sintered; the sintered product may be subjected to hardening or tempering treatments if desired. Also disclosed is a continuous method for carrying out both cryogenic embrittlement impaction, and coating. A mass of liquid N.sub.2 and metal pieces are circulated in a properly oriented tube so that in one zone a true slurry exists with liquid N.sub.2 in intimate contact with the metal pieces; in another zone the metal pieces are withdrawn from the slurry to momentarily increase in temperature. Fragmenting occurs substantially in said one zone and cold-working substantially in said another zone, while progressive anti-oxidation coating of the comminuted particles occurs in both zones. A second embrittling method involves dissolving the carbon in ferrous scrap metal having a critical predetermined carbon content, quenching the metal to produce substantially all martensite, and impacting the treated metal while simultaneously coating with an anti-oxidizing agent.
A method of making sintered shapes from ferrous-based metallic particles containing maganese and silicon, the latter having been cryogenically comminuted, the steps comprising:
A method of making an intermediate powder, comprising:
A method of making a powder compact, comprising:
A method of making sintered shapes from ferrous-based metallic particles containing oxidizable ingredients at conventional sintering temperatures and atmospheres, the latter having a substantially martensitic structure, the steps comprising:
A method of making an intermediate powder, comprising:
A method of making a powder compact, comprising:
A continuous method of improving the sinterability and compactability of ferrous based scrap converted to powder, the improvement comprising the steps of:
A continuous method of making an intermediate ferrous powder having improved sinterability and compactability, the process comprising:
A method of making sintered shapes from metallic particles containing Mn and Si, the steps comprising:
A method of making sintered shapes from iron based metallic particles containing oxidizable ingredients, the latter having been cryogenically comminuted, the steps comprising:
A method of making a powder compact, comprising:
Dependencies are inferred from the claim text.