Measurement of the thickness of the sprayed nickel coatings on large-sized cast iron products
- Ph.D., Dr.Sci. professor Saint-Petersburg Mining University
Abstract
Modern industries increasingly use automatic spraying of heat-resistant Nickel coating with a thickness of T = 1-3 mm for large-size parts made of cast iron with nodular graphite. The process of coating application is characterized by time-dependent behavior of its relative magnetic permeability, μс , that is a function of relaxation time, which can be as long as 24 hours, and by μс deviation from point to point on the surface. Aspects of eddy-current phase method for measuring the T value are considered. The structure of four- winding eddy current transformer transducers is described and results of calculation and optimization of their parameters are presented. The influence of controlled and interfering parameters is considered. Based on the above results, a two-channel combined transducer is developed providing measurement error of ΔТ ≤ ±(0.03T + 0.02) mm in the shop environment in the process of coating application and in the final product check. Results of tests on reference specimens and of application in production processes are presented.
References
- Babadzhanov L.S., Babadzhanova M.L. Metrological support of coating thickness measurements. Moscow: Izdatel'stvo standartov, 2004, р.264 [in Russian].
- Dorofeev A.L. Theory and industrial use of eddy current method. Moscow: Mashinostroenie, 1969, р.96 [in Russian].
- Dorofeev A.L., Kazamanov Ju.G. Electromagnetic defectoscopy. Moscow: Mashinostroenie, 1980, р.232 [in Russian].
- Konstantinov V.V. Material engineering for electroplaters. Moscow: Vysshaja shkola, 1989, р.80 [in Russian].
- Non-destructive testing. Eddy-current testing: Spravochnik: in 7 vols. Ed. by V.V.Kljueva. Moscow: Mashinostroenie, 2003. Vol.2. Book.2, p.347 [in Russian].
- Potapov A.I., Sjas'ko V.A. Non-destructive methods and means of coating thickness and products testing. Scientific, guidance, reference manual methodic. St.Petersburg: Gumanistika, 2009, р.904 [in Russian].
- Sjas'ko V.A., Ivkin A.E. Maintenance of reliability of results of metal coating thickness measurements by magnetic and eddycurrent methods in the conditions of machine-building manufactures. Metrologija. 2011. N 2, p.3-12 [in Russian].
- Bailey D. Shielded Eddy Current Probes // Material Evaluation. 1983. N 7. Vol.41. P.776-778.
- Blitz J. Electrical and Magnetic Methods of Nondestructive Testing. London: Chapman and Hall, 1997. 261 p.
- Buvat F. Eddy current modeling of ferrite-cored probes // Review of Progress in QNDE. Vol.24. 2005. P.463-470.
- Davis J. Mathematic formulas and refferences for nondestructive tasting – Eddy Current // J.Davis, M.King. Las Vegas: NV: Art Room Corporation, 2001. 136 р.
- Hansen J. Back to basics: The eddy current inspection // Insight. 2004. N 5. Vol.46. P.24-28.
- Le Ber L. Advanced of simulation and expertise capabilities in CIVA platform // Review of Progress in QNDE. 2006. Vol.25. P.684-691.
- Ohshima K. Research on numerical analyses modeling of SCC on eddy current testing / K.Ohshima, M.Hashimoto // Journal of the JSAEM. 2002. N 10. P.384-388.
- Syasko V.A. Eddy current thickness monitoring of aerospace technics coatings and constructions / V.A.Syasko, I.V.Pilatova, A.E.Ivkin // 18th World Conference on Nondestructive Testing. Durban, South Africa, 16-20 April, 2012. P.13. URL: http://www.ndt.net/article/wcndt2012/papers/13_wcndtfinal00013.pdf
- Syasko V.A. Optimization of structure and operation algorithms for electromagnetic plated coatings thickness meters with the use of digital technologies / V.A.Syasko, A.S.Bulatov, I.S.Pivovarov // 17th World Conference on Nondestructive Testing. Shanghai, China. 25-28 October. 2008. 5 p.