Patent
Method and an apparatus for flaw detection
| العنوان: | Method and an apparatus for flaw detection |
|---|---|
| Patent Number: | 5,934,805 |
| تاريخ النشر: | August 10, 1999 |
| Appl. No: | 08/807,459 |
| Application Filed: | February 27, 1997 |
| مستخلص: | The surface of the member to be inspected is covered with powder deposited by using, for example, static electricity prior to the flaw detection. The member surface is covered so as to be partly exposed by setting the average thickness of the powder layer to 0.1D-0.6D, where D is the average particle diameter of the powder, under an assumption that the powder particles in the powder layer are virtually leveled into a uniform thickness film. Subsequently, the surface region of the member is heated by high frequency induction heating, and then the temperature distribution on the surface is measured with a radiation thermometer. The part for which the temperature measured is different from the surroundings is judged as a flaw. The surface of the member is covered with the powder so that the surface emissivity becomes almost uniform, and the resulting temperature distribution measured with the radiation thermometer becomes almost equal to the real one. Therefore, flaws existing on the surface of the member are precisely detected according to the measurement with the radiation thermometer even in the case that there are parts of low emissivity, such as handling marks, on the surface. |
| Inventors: | Endo, Toshio (Aichi-ken, JPX); Yagi, Tomikazu (Aichi-ken, JPX); Yamada, Ryuzo (Chita, JPX); Ishikawa, Nobuo (Chita, JPX); Yano, Taizo (Nagoya, JPX) |
| Assignees: | Daido Tokushuko Kabushika Kaisha (Nagoya, JPX) |
| Claim: | What is claimed is |
| Claim: | 1. A method for detecting flaws on a surface of a member to be inspected comprising the steps of |
| Claim: | forming a powder layer on said surface of said member by depositing dry powder thereon so that said surface is partly exposed |
| Claim: | heating the surface region of said member by high frequency induction heating; |
| Claim: | measuring the temperature distribution on said surface of the heated member covered with said powder layer according to the energy emission from said surface of the member by a radiation thermometer; |
| Claim: | detecting the flaws on said member according to said temperature distribution on said surface of said member; and |
| Claim: | removing said powder layer and determining the average thickness of said powder layer after removal of the powder, said average thickness being between 0.1D-0.6D, where D is an average powder particle diameter under an assumption that the powder particles in said powder layer are dispersed into a uniform thickness film. |
| Claim: | 2. The method according to claim 1 wherein said average thickness of said powder layer is 0.25D-0.5D. |
| Claim: | 3. A method for detecting flaws on a surface of a member to be inspected comprising the steps of |
| Claim: | forming a powder layer on said surface of said member by depositing dry powder thereon so that said surface is partly exposed with a surface exposing ratio 2-70%; |
| Claim: | heating the surface of said member by a high frequency induction heating; |
| Claim: | measuring a temperature distribution on said surface of the heated member covered with said powder layer according to an energy emission from said surface of the member by a radiation thermometer; and |
| Claim: | detecting the flaws on said member according to said temperature distribution on said surface of said member. |
| Claim: | 4. The method according to claim 3 wherein the average thickness of said powder layer is 0.1D-0.6D, where D is the average particle diameter of said powder, under an assumption that the powder particles are virtually leveled into a uniform thickness film. |
| Claim: | 5. The method according to claim 3 wherein said surface exposing ratio is 5-40%. |
| Claim: | 6. The method according to claim 5, wherein said powder layer on said surface of said member has an average thickness of said powder layer of 0.25D-0.5D. |
| Claim: | 7. An apparatus for detecting flaws on a surface of a member comprising |
| Claim: | a transportation line for transporting said member to be inspected; |
| Claim: | a powder deposition device mounted on said transportation line and configured to form a powder layer on said surface of said member by depositing dry powder thereon so that said surface is partly exposed by setting an average thickness of said powder layer to 0.1D-0.6D, where D is an average particle diameter of said powder, under an assumption that the powder particles in said powder layer are dispersed into a uniform thickness film; |
| Claim: | a high frequency induction heating device mounted on said transportation line for heating the surface of said member; |
| Claim: | a radiation thermometer for measuring a temperature distribution on said surface of the heated member covered with said powder; and |
| Claim: | a detecting device for detecting said flaws on said member according to said temperature distribution. |
| Claim: | 8. The apparatus according to claim 7 wherein said high frequency induction heating device comprises a heating coil having a cavity into which said member is inserted, and wherein the Lc/Dcmax is less than 1/2, where Lc is the coil length and Dcmax is the maximum cross sectional dimension of said cavity. |
| Claim: | 9. The apparatus according to claim 8 wherein said heating coil has an aperture formed through the wall thereof from inside to outside, and wherein said radiation thermometer measures the temperature distribution on said surface of the member in said heating coil through said aperture. |
| Claim: | 10. The apparatus according to claim 8 wherein said radiation thermometer measures the temperature distribution on said surface of the member in said heating coil from an inclined direction through a gap between said heating coil and said member inserted thereinto. |
| Claim: | 11. The apparatus according to claim 7 wherein said radiation thermometer detects the temperature distribution on said surface of said member in transportation along a predetermined detecting line set in a direction crossing with a transportation direction of said member further comprising |
| Claim: | a temperature distribution data generating means which performs the sampling of the output from said radiation thermometer at a designated sampling timing, thereby generating sets of temperature distribution profile data along said detecting line at a position determined on the surface of said member corresponding to said sampling timing; |
| Claim: | a sampling commander which commands said temperature distribution data generating means to perform said sampling at a designated time interval corresponding to a transportation speed of said member so that said temperature distribution data generating means generates said sets of said temperature profile data which correspond to different positions on said surface of said member in said transportation direction; and |
| Claim: | a flaw data generating means which generates flaw data at least for specifying the position of said flaws on said surface of said member according to said sets of temperature profile data. |
| Claim: | 12. The apparatus according to claim 11 further comprising |
| Claim: | a flaw removing device which is movable along said surface of said member and removes a flaw existing on said surface; |
| Claim: | a moving mechanism which moves said flaw removing device independently in two or more directions crossing each other so as to be able to position said flaw removing device at a flaw site on said surface of said member; |
| Claim: | a moving commander which commands said moving mechanism to move said flaw removing device to a flaw site determined according to a flaw data. |
| Claim: | 13. The apparatus according to claim 12 comprising a member supporting means for supporting said member so as to be fixedly positioned in a designated site; |
| Claim: | wherein said flaw removing device removes said flaws on said member supported by said member supporting means. |
| Claim: | 14. The apparatus according to claim 7; |
| Claim: | wherein a bar-like member with a square-like axial cross section is used as said member to be inspected; |
| Claim: | wherein said bar-like member is transported in the longitudinal direction thereof so that one diagonal line of said square-like axial cross section is almost vertically directed; |
| Claim: | wherein said transportation line comprises a pair of member transportation rollers which pinches said member from above and below, respectively, and whose roller surface has a V-shaped cross section corresponding to the corner shape of said square-like axial cross section of said member. |
| Claim: | 15. An apparatus for detecting flaws on a surface of a member to be inspected comprising |
| Claim: | a powder deposition device mounted on said transportation line and configured to form a powder layer on said surface of said member by depositing dry powder thereon so that said surface is partly exposed with an surface exposing ratio of 2-70%; |
| Claim: | a radiation thermometer for measuring the temperature distribution on said surface of the heated member covered with said powder; and |
| Claim: | a detecting device for detecting flaws on said member according to said temperature distribution. |
| Current U.S. Class: | 374/5; 374/121; 374/126 |
| Current International Class: | G01J 500; G01N 2572 |
| Patent References Cited: | 3020745 February 1962 Sielicki 3504524 April 1970 Maley 4247306 January 1981 Berge 4317978 March 1982 Nebesar 4408903 October 1983 Baldasarri 4430913 February 1984 Williamson 4480928 November 1984 Halsor et al. 4965451 October 1990 Solter 5069005 December 1991 Hovland et al. 5111048 May 1992 Devitt et al. |
| Primary Examiner: | Gutierrez, Diego |
| Assistant Examiner: | Hirshfeld, Andrew |
| Attorney, Agent or Firm: | Snider, Ronald R. |
| رقم الانضمام: | edspgr.05934805 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |