Sintered materials

• US 4,970,049 A
• Filed: 10/06/1988
• Issued: 11/13/1990
• Est. Priority Date: 10/10/1987
• Status: Expired due to Term

• Current Assignee: Brico Engineering Limited Holbrook Lane Coventry West Midlands CV6 4BG
• Original Assignee: Brico Engineering Limited (Apollo Global Management, Inc.)
• Inventors: Baker, Andrew R., Kettle, Richard L.
• Primary Examiner(s): Lechert, Jr., Stephen J.
• Assistant Examiner(s): Nigohosian, Jr., Leon
• Application Number:
  US07/254,169
• Time in Patent Office: 768 Days
• Field of Search: 75/241, 75/243, 75/246, 75/5 BA, 75/232, 75/230, 75/231, 419/11, 419/38, 419/26, 419/10, 419/25, 419/26, 419/27, 419/38
• US Class Current: 419/11
• CPC Class Codes: C22C 33/0207 Using a mixture of prealloyed powders or a master alloy mixtures of metal powder in general B22F1/09
• CPC Class Codes: C22C 33/0242 using the impregnating technique impregnating articles in general B22F3/26
• CPC Class Codes: C22C 33/0264 the maximum content of each alloying element not exceeding 5%

Abstract

Sintered ferrous materials are described having a composition in wt % lying within the ranges of C 0.8-1.5/W 1-4.4/Mo 1-4.4/V 1-2.6/Cr 1.3-3.2/Others 3 max./Fe balance. The material may be made by a method comprising the steps of mixing between 40 and 70 wt % of a powder having a composition in wt % within the ranges C 0.45-1.05/W 2.7-6. 2/Mo 2.8-6.2/V 2.8-3.2/Cr 3.8-4.5/Others 3.0 max./Fe balance with between 60 and 30 wt % of an iron powder and from 0.4 to 0.9 wt % of carbon powder, pressing a green body of the article from the mixed powder and then sintering the green body. The material may optionally contain sulphur, metallic sulphides. The material may be infiltrated.

Claims

1. A method of making a sintered ferrous material, the method comprising the steps of mixing between 40 and 70 wt % of an alloyed powder having a composition in wt % within the ranges C 0.45-1.05/W 2.7-6.2/Mo 2.8-6.2/V 2.8-3.2/Cr 3.8-4.5/Others 3.0 max./Fe balance with between 60 and 30 wt % of an iron powder and from 0.4 to 0.9 wt % of carbon powder, pressing a green body of the article from the mixed powder and then sintering the green body.

2. A method according to claim 1 wherein a minimum total of 0.8 wt % carbon is present.

3. A method according to claim 1 further including the step of mixing in up to 1 wt % of sulphur.

4. A method according to claim 1 further including the step of mixing in up to 5 wt % of one or more metallic sulphides.

5. A method according to claim 1 further including the step of mixing in from 4 to 6 wt % of copper powder.

6. A method according to claim 1 further including the step of infiltrating the material with a copper alloy.

7. A method according to claim 1 further including the step of cryogenically treating the sintered material.

8. A method as claimed in claim 1 wherein the composition and conditions are such that the sintered material comprises a martensitic matrix containing alloy carbides and bainite phases.

9. A method as claimed in claim 7 further comprising tempering the cryogenically treated sintered material at a temperature in the range of about 575°

C. to 710°

C. such that the alloy matrix comprises tempered martensite with spheroidized alloy carbides and bainite regions.