US4352308A
Expired / Lapsed
US
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Method of cutting cast iron with Si3 N4 composite cutting tool material
Assignee: Ceradyne Inc
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Filing: 1980-03-10
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Granted: 1982-10-05
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Expires: 2000-03-10
Abstract
Abstract A method of machining cast iron by using a ceramic cutting tool of specific composition at specified removal rates which results in increased tool life.
Inventors
- 👤 Shyam K. Samanta
- 👤 Krishnamoorthy Subramanian
- 👤 Andre Ezis
- 👤 David Moskowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:26
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; B; B23; B23B; B23B27/00; B23B27/14; B23B27/148; Y; Y10; Y10T; Y10T82/00; Y10T82/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
76 words
A method of machining cast iron, comprising: deploying a ceramic as a cutting tool in continuous or interrupted machine cutting of cast iron at surface speeds of 50-7500 sfm and at depths of cut of at least 0.02 inches, wherein said ceramic cutting tool is a hot pressed Si 3 N 4 based ceramic cutting tool containing only one metal oxide member of the group consisting of Y 2 O 3 , ZrO 2 and MgO.
Claim 2
Independent Claim
76 words
A method of machining cast iron, comprising: deploying a ceramic as a cutting tool in continuous or interrupted machine cutting of cast iron at surface speeds of 50-7500 sfm and at depths of cut of at least 0.02 inches, wherein said ceramic cutting tool is a hot pressed Si 3 N 4 based ceramic cutting tool containing only one metal oxide member of the group consisting of Y 2 O 3 , ZrO 2 and MgO.
Claim 3
Dependent Claim
50 words
The method of claim 1 in which said ceramic is limited to the ternary system of Si 3 N 4 .SiO 2 metal oxide and the ceramic is hot pressed to render a secondary binder phase in the grain boundary of the matrix providing a thermal shock parameter exceeding ##EQU5##
Claim 4
Independent Claim
103 words
A method of manufacturing cast iron, comprising: deploying a shaped ceramic as a cutting tool in continuous of interrupted machine cutting of solid cast iron stock at speeds of 50-7500 sfm, at a depth of cut of 0.2-0.25 inches and a feed of 0.01-0.044 in/rev, wherein said ceramic is a hot pressed Si 3 N 4 based ceramic containing one ingredient selected from the group consisting of 4-12% Y 2 O 3 , 1-13% ZrO 2 , 1-5% MgO, the pressure of pressing having been maintained continuously during heating at an ultimate pressing temperature of 1700°-1750° C. until substantially full density is obtained.
Claim 5
Independent Claim
103 words
A method of manufacturing cast iron, comprising: deploying a shaped ceramic as a cutting tool in continuous of interrupted machine cutting of solid cast iron stock at speeds of 50-7500 sfm, at a depth of cut of 0.2-0.25 inches and a feed of 0.01-0.044 in/rev, wherein said ceramic is a hot pressed Si 3 N 4 based ceramic containing one ingredient selected from the group consisting of 4-12% Y 2 O 3 , 1-13% ZrO 2 , 1-5% MgO, the pressure of pressing having been maintained continuously during heating at an ultimate pressing temperature of 1700°-1750° C. until substantially full density is obtained.
Claim 6
Dependent Claim
30 words
The method of claim 3, in which cutting is carried out for at least 20 minutes and said tool experiencing no thermal cracking or wear in excess of 0.01 inches.
Claim 7
Dependent Claim
28 words
The method of claim 3, in which said ingredient is ZrO 2 and the transverse rupture strength of said material is at least 70,000 psi at 1200° C.
Claim 8
Dependent Claim
58 words
The method of claim 5, in which said pressing is carried out for at least two hours at said temperature to effect a stable silicate phase in the grain boundary of said Si 3 N 4 matrix, which phase serves as a binder and is inert to maintain the oxidation resistance of said material at a high level.
Claim 9
Dependent Claim
33 words
The method of claim 6, in which Si 3 N 4 and said secondary phase binder combine to provide said material with a thermal shock parameter at 1200° C. of at least ##EQU6##
Claim 10
Independent Claim
102 words
A method of cutting cast iron, comprising: deploying a cutting tool consisting essentially of Si 3 N 4 based ceramics containing a matrix of Si 3 N 4 and a dispersion of SiO 2 and 4-12% Y 2 O 3 or 1-13% ZrO 2 and having a predetermined silicate secondary phase to continuously or interruptedly cut solid cast iron for at least 30 minutes at speeds of 50-7500 sfm, at a depth of cut of at least 0.125 inches, said cutting being particularly characterized by the absence of tool material failure by either thermal cracking or wear of greater than 0.01 inch.
Claim 11
Independent Claim
102 words
A method of cutting cast iron, comprising: deploying a cutting tool consisting essentially of Si 3 N 4 based ceramics containing a matrix of Si 3 N 4 and a dispersion of SiO 2 and 4-12% Y 2 O 3 or 1-13% ZrO 2 and having a predetermined silicate secondary phase to continuously or interruptedly cut solid cast iron for at least 30 minutes at speeds of 50-7500 sfm, at a depth of cut of at least 0.125 inches, said cutting being particularly characterized by the absence of tool material failure by either thermal cracking or wear of greater than 0.01 inch.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-10-04 | 1986-04-05 | 1986-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-04 | 1990-04-05 | 1990-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-04 | 1994-04-05 | 1994-10-05 | $7700.00 | Window Closed / Lapsed |