# US 4,015,780 A · Powder forming

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,015,780 A
- Document ID: US4015780A
- Status: Granted
- Kind: A
- Application number: 05/574,640
- Filed: 1975-05-05
- Granted: 1977-04-05
- Earliest claimed: 1975-05-05
- Assignees: BOC Limited
- Inventors: Robert Gilmore Hall
- Web page: https://patentgrep.com/patent/US4015780A

## CPC

- B22F 9/04: starting from solid material, e.g. by crushing, grinding or milling ({C22C1/1084 takes precedence}; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C)
- Y10S 241/37: Cryogenic cooling
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A process for producing powdered metal which comprises taking metal swarf, removing oil and grease from the swarf, cooling the swarf to a temperature below -20.degree. C and milling the cooled swarf to form powder.

## Claims

### Claim 1

A process for producing powdered metal which comprises taking metal swarf, substantially removing oil from the swarf, reducing the metal swarf to a particle size of about 6 mm diameter, then substantially removing residual oil and grease from the said particles, cooling the said particles of swarf to a temperature in the range of about minus 20.degree. C to minus 100.degree. C to considerably reduce the impact strength of the swarf particles, and introducing the so cooled swarf particles into a comminuting mill wherein coolant is introduced into the mill during the milling operation so as to maintain the swarf particles at the said temperature range during comminution to a powdered metal having a particle size in the range of about -40 to +350 BSS for producing metal powder suitable for compaction and forging by conventional powder metallurgy techniques.

### Claim 2 (depends on 1)

A process as claimed in claim 1, wherein said cooling is by direct contact with a coolant.

### Claim 3 (depends on 1)

A process as claimed in claim 1, wherein said cooling is effected indirectly by using a coolant.