US3939404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of testing for and preventing the possibility of cracking, spalling or like defects in rolling mill rolls by determining the rate of change in hardness
Assignee: ArcelorMittal Dofasco Inc
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Filing: 1974-07-10
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Granted: 1976-02-17
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Expires: 1994-07-10
Abstract
Abstract In a method of testing for and preventing the possibility of cracking, spalling or like defects in a rolling mill roll surface the surface is scanned to provide a representation of the hardness and/or the magnetic conductivity. The presence at a location of a rate of change of this characteristic of greater than a predetermined amount foreshadows the possibility of the occurrence of such a defect at this location. The roll is then subjected to an operation consisting of removal of the surface portion or heat treatment until the rate of change is below another predetermined amount. Preferably the method used to measure magnetic conductivity is eddy current testing. The removal operation may take place in steps until the rate of charge is below the another rate of charge.
Inventors
- 👤 William H. Tait
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:20
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/80
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
136 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining the rate of change of hardness along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change of hardness along the reference direction exceeds the said maximum value removing material from the roll including the tested surface until the rate of change of hardness is below another predetermined maximum value.
Claim 2
Independent Claim
136 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining the rate of change of hardness along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change of hardness along the reference direction exceeds the said maximum value removing material from the roll including the tested surface until the rate of change of hardness is below another predetermined maximum value.
Claim 3
Dependent Claim
20 words
A method as claimed in claim 1, wherein the reference direction is a straight line parallel to the roll axis.
Claim 4
Dependent Claim
26 words
A method as claimed in claim 1, wherein the said rate of change of hardness is less than 2.5 units of shore hardness per linear inch.
Claim 5
Dependent Claim
50 words
A method as claimed in claim 1, wherein the first-mentioned predetermined rate of change of hardness is about 2.5 units of shore hardness per linear inch, and the said another predetermined maximum value applicable after the removal of the material is about 3.6 units of shore hardness per linear inch.
Claim 6
Dependent Claim
70 words
A method as claimed in claim 1, wherein the said removal of material is performed as a series of successive steps, and including the further steps of determining the rate of change of hardness along the reference direction between each two immediately successive steps, and terminating the removal of material when the preceding determination shows that the rate of change of hardness is less than the said another predetermined value.
Claim 7
Independent Claim
140 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining by means of an eddy current detector the rate of change of magnetic conductivity along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change along the reference direction exceeds the said maximum value removing material from the roll including the tested surface until the rate of change is below another predetermined maximum value.
Claim 8
Independent Claim
140 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining by means of an eddy current detector the rate of change of magnetic conductivity along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change along the reference direction exceeds the said maximum value removing material from the roll including the tested surface until the rate of change is below another predetermined maximum value.
Claim 9
Dependent Claim
20 words
A method as claimed in claim 6, wherein the reference direction is a straight line parallel to the roll axis.
Claim 10
Dependent Claim
64 words
A method as claimed in claim 6, wherein the said removal of material is performed as a series of successive steps, and including the further steps of determining the rate of change along the reference direction between each two immediately successive steps, and terminating the removal when the preceding determination shows that the rate of change is less than the said another predetermined value.
Claim 11
Independent Claim
152 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining the rate of change of hardness along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change of hardness along the reference direction exceeds the said maximum value heat-treating the roll, c. determining the rate of change along the reference direction on the heat-treated roll, and d. repeating the steps b and c as necessary until the rate of change is below another predetermined maximum value.
Claim 12
Independent Claim
152 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining the rate of change of hardness along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change of hardness along the reference direction exceeds the said maximum value heat-treating the roll, c. determining the rate of change along the reference direction on the heat-treated roll, and d. repeating the steps b and c as necessary until the rate of change is below another predetermined maximum value.
Claim 13
Dependent Claim
20 words
A method as claimed in claim 9, wherein the reference direction is a straight line parallel to the roll axis.
Claim 14
Dependent Claim
26 words
A method as claimed in claim 9, wherein the said rate of change of hardness is less than 2.5 units of shore hardness per linear inch.
Claim 15
Independent Claim
158 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining by means of an eddy current detector the rate of change of magnetic conductivity along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change along the reference direction exceeds the said maximum value heat-treating the roll, c. determining the rate of change along the reference direction on the heat-treated roll, and d. repeating the steps b and c as necessary until the rate of change is below another predetermined maximum value.
Claim 16
Independent Claim
158 words
A method of testing for and at least reducing the possibility of the occurrence of cracking, spalling or like defects in the exterior cylindrical surface of a cylindrical steel rolling mill roll, the method including the steps of: a. determining by means of an eddy current detector the rate of change of magnetic conductivity along a reference direction for at least a part of the roll surface to find locations therealong having rates of change greater than a predetermined maximum value known to foreshadow the possibility of the occurrence of defects for the roll and the conditions to which it is subjected in operation, and b. when the rate of change along the reference direction exceeds the said maximum value heat-treating the roll, c. determining the rate of change along the reference direction on the heat-treated roll, and d. repeating the steps b and c as necessary until the rate of change is below another predetermined maximum value.
Claim 17
Dependent Claim
20 words
A method as claimed in claim 12, wherein the reference direction is a straight line parallel to the roll axis.
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) | 1979-02-16 | 1979-08-18 | 1980-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-16 | 1983-08-18 | 1984-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-16 | 1987-08-18 | 1988-02-17 | $7700.00 | Window Closed / Lapsed |