Tver State Technical University, Tver, Russia:
D. A. Barchukov, Cand. Eng., Associate Prof., Head of the Dept. of Technology of Metals and Materials Science, e-mail: bda@mail.ru
L. E. Afanasyeva, Cand. Phys.-Math., Associate Prof. of the Dept. of Technology of Metals and Materials Science
V. V. Izmailov, Dr. Eng., Prof. of the Dept. of Applied Physics
M. V. Novoselova, Cand. Eng., Associate Prof., Dept. of Applied Physics

The results of experimental studies of the microstructure and wear resistance of R2M8 high-speed steel obtained by pulse-arc surfacing with flux-cored wire are presented. At the stage of cooling during surfacing in the temperature range of martensitic transformation (from 300 to 60 ºC), shock surface plastic deformation of the bead was carried out. It is established that the deposited metal has a fine-grained structure with an average grain diameter of 10–11 μm. The phase composition of the deposited high-speed steel is martensite, residual austenite, dispersed eutectic and special carbides. The average level of microhardness is about 7200 MPa. The conducted studies have shown high efficiency of impact plastic deformation of the deposited high-speed steel during cooling after surfacing in the temperature range corresponding to the state of steel superplasticity. Impact surface plastic deformation, carried out under the conditions of the superplastic state of steel, led to an increase in microhardness up to 9000 MPa, the amount of residual austenite in the deposited metal decreased from 50 to 4 %. Wear tests have shown that surface plastic deformation increases the wear resistance of high-speed steel by 1.5 times.
The authors are grateful to A. Yu. Lavrentiev, Cand. Eng., for assistance in sample preparation.

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