University of Guelph (Guelph, Canada):

W.I. Sawich

Dneprodzerzhinsk Technical University (Dneprodzerzhinsk, Ukraine):

O.G. Cherneta

A.N. Korobochka

East-European Metallurgical Division of JSC Mechel (Tyrgoviste, Romania):

A.B. Sychkov

Iron and Steel Institute of the National Academy of Sciences of the Ukraine (Dnepropetrovsk, Ukraine):

A.M. Nesterenko

V.L. Pliuta

RUP “Byelorussian Steel Works” (Zhlobin, Belarus):

M.A.Murikov, ofwork@bmz.gomel.by

A study of the aspects of forming highly resistant coatings in the surface zone of tool steels and solid carbide inserts by a dual-stage method was made. At the first stage of the method, pure Ta or Nb coatings were electrolytically deposited on samples of tool steel and solid carbide insert in a molten salt bath containing Ta and Nb fluorides. At the second stage, the electrically deposited coating of Ta (Nb) was subjected to carburizing or boriding to form carbide (TaC, NbC) or boride (TaB, NbB) cladding layers.

It has been found that formation of cladding layers consisting of highly resistant carbide (boride) phases in the surface zone of the samples under study is determined by the carbon (boron) atoms outsourcing, that the carbide (boride) coatings deposited by the disclosed method have a higher specific density (free of pores, subsurface cracks and other defects) and a better bond to the base metal, that the intensive outsourcing of carbon (boron) atoms prevents decarburization of the surface zone in the material under study – tool steel and solid carbide insert for cutting tools, that the required thickness and high surface quality of the coating provided by the invented method are insured by the controlled conditions of the electrochemical deposition, including conditions at the initial stage of the process and that the application of the invented method looks promising for producing strengthened working surfaces on replaceable parts in the mining mining-metallurgical equipment, on rolls and guides of cogging and section mills, and on parts of internal combustion engines (ICE).

Machining operations tests carried out to check the durability of cutting tool inserts covered with TaC deposited by the invented method, have demonstrated efficiency of these inserts for finishing cuts. The invented method has been found to be promising for extending the service life of parts in the mining-metallurgical and machine-building equipment.

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