On the issue of selecting and optimizing parameters of continuous laser welding of cast iron

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 technology The problem was solved by the linear programming method. The solution is presented in the form of a graph in Fig. 5. Fig. 5. Optimal laser power and welding speed depending on the weld penetration The dependence in Fig. 5 shows that welding of small thicknesses (up to 1 mm) is optimally carried out with a minimum power, and the weld seam penetration is regulated by changing the laser speed. A high speed is optimal when welding large thicknesses (over 1 mm), while the optimum power increases linearly with raising the seam penetration. At a depth of more than 3 mm, the problem has no solution; it is impossible to obtain such a weld seam with the accepted intervals of varying technological parameters. Conclusion There are optimum laser welding parameters for each material. In this work the authors use the methods of regression analysis, gray relational analysis, linear programming to identify the dependence, which makes it possible to have a reasonable choice of technological parameters of continuous laser welding (laser power, welding speed) of cast iron to a 3-mm depth. It is found that welding of small thicknesses is optimal at a minimum power, welding of large thicknesses is optimal at a maximum speed. The findings in their pure form are valid for lamellar graphite cast irons having a pearlitic metal base when welding with an ytterbium fibre laser with a power of 0.6 to 1.3 kW at a speed of 14 to 56 mm/s with a 120-mm focal length. References 1. Olson D.L., Siewart T.A., Liu S., Edwards G.R. ASM Handbook . Vol. 6. Welding, brazing, and soldering . ASM International, 1993. 2873 p. 2. Gusev A.A. Perspektivy impul’snogo lazernogo legirovaniya i naplavki [Outlooks for pulse-laser alloying and pad welding]. Izvestiya Samarskogo nauchnogo tsentra Rossiiskoi akademii nauk = Proceedings of the Samara Scientific Center of the Russian Academy of Sciences , 2012, vol. 14, no. 6, pp. 247–253. 3. Lin C.-M., Chandra A.S., Morales-Rivas L., Huang S.-Y., Wu H.-C., Wu Y.-E., Tsai H.-L. Repair welding of ductile cast iron by laser cladding process: microstructure and mechanical properties. International Journal of Cast Metals Research , 2014, vol. 27, iss. 6, pp. 378–383. DOI: 10.1179/1743133614Y.0000000126. 4. Fu Q., Yi P., Xu P., Fan C., Yang G., Liu D., Shi Y. Microstructure formation and fracturing characteristics of grey cast iron repaired using laser. The Scientific World Journal , 2014, vol. 2014, p. 541569. DOI: 10.1155/2014/541569. 5. Piątkowski J., Grabowski A., Czerepak M. The influence of laser surface remelting on the microstructure of EN AC-48000 cast alloy. Archives of Foundry Engineering , 2016, vol. 16, iss. 4, pp. 217–221. DOI: 10.1515/afe- 2016-0112. 6. Matveev Yu.I., Kazakov S.S. Formirovanie struktur serogo chuguna v zone lazernogo vozdeistviya [Formation of structures of grey pig-iron in the zone of laser influence]. Vestnik NGIEI = Bulletin NGIEI , 2011, vol. 2, no. 1 (2), pp. 41–53.