TECHNOLOGICAL ASPECTS OF FRICTION TREATMENT OF PG-SR2 COATING FORMED BY LASER CLADDING

PG-SR2 powder having the Ni-Cr-B-Si alloying system is used for laser cladding on the parts operating in the conditions of wear, corrosion, erosion, and high temperatures. The extensive surface waviness and roughness resulting from laser cladding are currently eliminated by grinding with abrasive wheels. Previously, the authors showed the possibility of finishing friction treatment of the PG-SR2 coating with an indenter made of finely dispersed cubic boron nitride in the air under the load of 350 N. However, an increase in the load on the indenter during friction treatment can affect ambiguously. Besides, the state of the indenters after the friction treatment of the PG-SR2 coating has not been previously considered, what is one of the important aspects of the selection of technological parameters of friction treatment. Therefore, in the present work, the authors studied the hardness and quality of the PG-SR2 coating surface after the friction treatment under the loads on the indenter of 350 and 500 N, compared with the surface characteristics after the electro-polishing and grinding, and analyzed the surfaces of the indenters after such treatments. The study showed that during friction treatment under the load of 500 N, the processes of setting occur on the PG-SR2 coating surface leading to the formation of a surface with the increased roughness and preventing the maximum strain hardening of the coating. This causes the transfer of the coating material to the surface of the indenter tip. Chemical composition on the indenter surface after the friction treatment under the load of 350 N does not change. Moreover, such treatment forms the hardest and high-quality surface with the reduced roughness parameters and can be recommended as a finishing hardening operation for producing parts with the PG-SR2 coating.

NiCrBSi покрытия, laser cladding, NiCrBSi coatings, PG-SR2, friction treatment, profilometry, microindentation