US4539848A
Expired / Lapsed
US
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Method of determining grain size using ultrasonic waves
Assignee: Nippon Steel Corp
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Filing: 1984-07-25
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Granted: 1985-09-10
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Expires: 2004-07-25
Abstract
Abstract The grain size is expressed by the diameter of grains demarcated at high-angle grain boundaries, such as ferrite grains in ferritic steels. Ultrasonic waves having a frequency f are propagated through an object to be examined and its attenuation constant α is determined. Using the ratio f/α and equation C'.sub.j ≦f/α≦C'.sub.j+l where C' j and C' j+l are constants and j is a constant between 1 and 4, the order j of the region to which the value of f/α belongs is determined. Then the grain diameter D is derived from equation ##EQU1## using an integer n j and constant A j predetermined for the order j of each region.
Inventors
- 👤 Hideo Takafuji
- 👤 Shoichi Sekiguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:56
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/04; G01N29/11; G01N2291/00; G01N2291/01; G01N2291/015; G01N2291/02; G01N2291/028; G01N2291/0289; G01N2291/10; G01N2291/101
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
98 words
A method of determining grain size using ultrasonic waves which comprises propagating ultrasonic waves having a frequency f through an object to be examined, determining the attenuation constant α of the ultrasonic waves, determining the order of the region j to which the value of f/α belongs using the ratio f/α and equation C'.sub.j ≦f/α≦C'.sub.j+1 where C' j and C' j+1 are constants and j is a constant between 1 and 4, and deriving the grain diameter D from equation ##EQU9## using an integer n j and constant A j predetermined for the order j of each region.
Claim 2
Independent Claim
98 words
A method of determining grain size using ultrasonic waves which comprises propagating ultrasonic waves having a frequency f through an object to be examined, determining the attenuation constant α of the ultrasonic waves, determining the order of the region j to which the value of f/α belongs using the ratio f/α and equation C'.sub.j ≦f/α≦C'.sub.j+1 where C' j and C' j+1 are constants and j is a constant between 1 and 4, and deriving the grain diameter D from equation ##EQU9## using an integer n j and constant A j predetermined for the order j of each region.
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) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |