US4336077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of cryogenically hardening an insert in an article
Assignee: Caterpillar Inc
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Filing: 1980-03-03
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Granted: 1982-06-22
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Expires: 2000-03-03
Abstract
Abstract A method of cryogenically hardening and expanding an insert in an article is disclosed. Particularly, gray iron piston ring insert (14) having an austenitic matrix is treated in a piston body (12) by impinging a cryogenic medium thereon. This changes the matrix microstructure of the insert to at least about 25 Vol. % martensite and desirably increases the hardness level thereof to at least about 95 on the Rockwell "B" scale in the desired regions thereof. The volume of the insert is also expanded to be more securely received in the piston body.
Inventors
- 👤 J. Michael Leach
- 👤 Walter L. Harvey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:24
CPC Classifications
C; C21; C21D; C21D6/00; C21D6/04; B; B23; B23P; B23P15/00; B23P15/10; F; F16; F16J; F16J9/00; F16J9/12; F16J9/22; F05; F05C; F05C2201/00; F05C2201/02; F05C2201/021; F05C2251/00; F05C2251/04; F05C2251/042; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49249; Y10T29/49256; Y10T29/49274
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
49 words
A method of cryogenically hardening an insert (14) in an article (12) comprising: Step (a) casting an article (12) at least partly around an insert (14); and Step (b) cryogenically hardening and expanding at least a portion of the insert (14) more tightly into engagement with the article (12).
Claim 2
Independent Claim
49 words
A method of cryogenically hardening an insert (14) in an article (12) comprising: Step (a) casting an article (12) at least partly around an insert (14); and Step (b) cryogenically hardening and expanding at least a portion of the insert (14) more tightly into engagement with the article (12).
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein Step (a) includes casting the article (12) of an aluminum based material and selecting the insert (14) of a ferrous based material having a coefficient of expansion approaching that of aluminum.
Claim 4
Dependent Claim
39 words
The method of claim 1 wherein Step (a) includes selecting the material of the article (12) to be basically aluminum and the material of the insert (14) to be a ferrous based material having a basically austenitic matrix microstructure.
Claim 5
Dependent Claim
30 words
The method of claim 3 wherein Step (b) includes modifying the microstructure of the insert (14) from a basically austenitic matrix to austenite and at least about 25 Vol.% martensite.
Claim 6
Dependent Claim
34 words
The method of claim 1 wherein Step (b) includes changing the microstructure of the insert (14) from a basically austenitic matrix ferrous based material to a matrix morphology having more than 50 Vol.% martensite.
Claim 7
Dependent Claim
28 words
The method of claim 1 including the step of precooling the article (12) and the insert (14) to a preselected temperature range below freezing prior to Step (b).
Claim 8
Dependent Claim
23 words
The method of claim 1 wherein Step (b) includes spraying the insert (14) with a cryogenic medium for a preselected period of time.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein Step (b) includes spraying the insert (14) with liquified nitrogen.
Claim 10
Dependent Claim
31 words
The method of claim 1 including Step (c) checking the hardness level obtained by Step (b) by visual observation of the influence of the insert (14) upon a magnetized element (62).
Claim 11
Independent Claim
55 words
A method of cryogenically hardening a piston ring insert (14) in a piston (12) comprising: Step (a) casting a material around the insert (14) and providing an assembly (10) of the piston (12) and the insert (14); and Step (b) cryogenically hardening and expanding the insert (14) more tightly into engagement with the piston (12).
Claim 12
Independent Claim
55 words
A method of cryogenically hardening a piston ring insert (14) in a piston (12) comprising: Step (a) casting a material around the insert (14) and providing an assembly (10) of the piston (12) and the insert (14); and Step (b) cryogenically hardening and expanding the insert (14) more tightly into engagement with the piston (12).
Claim 13
Dependent Claim
27 words
The method of claim 10 wherein Step (a) includes selecting the material of the insert to be cast iron having a matrix of a substantially austenitic microstructure.
Claim 14
Dependent Claim
22 words
The method of claim 11 wherein Step (b) includes modifying the matrix of the insert to at least about 25 Vol.% martensite.
Claim 15
Dependent Claim
21 words
The method of claim 10 including Step (c) checking the magnetic attraction of the insert (14) against a corresponding hardness level.
Claim 16
Dependent Claim
47 words
In a method of making a piston assembly (10) including a piston (12) and a piston ring insert (14), the improvement comprising: casting the piston (12) about the piston ring insert; and cryogenically hardening and expanding the insert (14) more tightly into engagement with the piston (12).
Claim 17
Dependent Claim
47 words
In a method of making a piston assembly (10) including a piston (12) and a piston ring insert (14), the improvement comprising: casting the piston (12) about the piston ring insert; and cryogenically hardening and expanding the insert (14) more tightly into engagement with the piston (12).
Claim 18
Dependent Claim
17 words
The method of claim 14 including the step of spraying a cryogenic medium upon the insert (14).
Claim 19
Dependent Claim
15 words
The method of claim 15 including the step of simultaneously rotating the piston assembly (10).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-21 | 1985-12-21 | 1986-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-21 | 1989-12-21 | 1990-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-21 | 1993-12-21 | 1994-06-22 | $7700.00 | Window Closed / Lapsed |