Chair “Physical Problems of Materials Science”, National Research Nuclear University “MEPhI”, Moscow, Russia:

V. I. Polskiy, Assistant Professor, e-mail: vipolskij@mephi.ru

V. L. Yakushin, Professor

P. S. Dzhumaev, Assistant

Chair “Laser physics”, National Research Nuclear University “MEPhI”, Moscow, Russia:

V. N. Petrovskiy, Assistant Professor

A large number of machinery components fails during operation due to various factors, such as: abrasive wear, impact loading, erosion, etc. Modern technology has different methods of hardening and recovery of parts for their lifetime increasing. One of the promising methods of restoration and strengthening is laser cladding — applying a metallic material layer on the surface by laser melting of powder, wire, etc, supplied to the laser irradiation zone. Laser surface cladding technique of cylindrical and flat samples, made of various structural steels, was developed. Heat resistant complex nickel-based alloy powder was used as cladding material. Laser cladding process was carried out on the “Scanner” and “Huffman HC-205” laser facilities. There were investigated the changes of microstructure and microhardness of laser processed samples, depending on laser radiation specific power and different methods of Ni-alloy powder application on sample surface. As a result, there were revealed the optimal technological regimes of laser processing, which lead to formation of clad layer with homogeneous microstructure. In comparison with initial material, this layer has the 2 times increased value of microhardness. Clad layer adhesion improves with increase of laser radiation specific power and reaches the optimum value at P = 800 W for “Huffman HC-205” and P = 1100 W for “Scanner” instal lation.The studies established the optimal modes of application of laser weld overlays on substrates of various sizes and configurations, which minimize the heat affected zone sizes and variations of hardness values, reducing the probability of occurrence of cracks and discontinuities.

1. Gribkov V. A., Grigorev F. I., Kalin B. A., Yakushin V. L. Perspektivnye radiatsionno-puchkovye tekhnologii obrabotki materialov (Prospective radiation beam metal processing technologies). Moscow : Kruglyy god, 2001. 528 p. 

2. Pereira A., Delaporte P., Sentis M., Cros A., Marine W., Basillais A., Thomas A. L., Leborgne C., Semmar N., Andreazza P., Sauvage T. Laser treatment of a steel surface in ambient air. Thin Solid Films. 2004. Vol. 453/454. pp. 16–21. 

3. Jiang W., Molian P. Nanocrystalline TiC powder alloying and glazing of H13 steel using a CO₂ laser for improved life of die-casting dies. Surface and Coatings Technology. 2001. Vol. 135. pp. 139–149. 

4. DiMelfi R. J., Sanders P. G., Hunter B., Eastman J. A., Sawley K. J., Leong K. H., Kramer J. M. Mitigation of subsurface crack propagation in railroad rails by laser surface modification. Surface and Coatings Technology. 1998. Vol. 106. pp. 30–43. 

5. Xia Y., Liu W., Xue Q. Comparative study of the tribological properties of various modified mild steels under boundary lubrication condition. Tribology International. 2005. Vol. 38. pp. 508–514. 

6. Sadovskiy V. D., Schastlivtsev V. M., Tabatchikova T. I., Yakovleva I. L. Lazernyy nagrev i struktura stali: atlas mikrostuktur (Laser heating and structure of steel: atlas of microstructures). Sverdlovsk : Ural Branch of USSR Academy of Sciences, 1989. 239 p. 

7. Petrovskiy V. N., Shtamm V. G., Dzhumaev P. S., Polskiy V. I. Lazernaya naplavka metallicheskikh poroshkov (Laser surfacing of metallic powders). Yadernaya fizika i inzhiniring = Nuclear physics and Engineering. 2012. Vol. 3, No. 4. pp. 1–7.