Actual Problems in Machine Building 2018 Vol. 5 No. 3-4

Actual Problems in Machine Building. Vol. 5. N 3-4. 2018 Materials Science in Machine Building ____________________________________________________________________ 130 WEAR-RESISTANT COATING WITH NbC ON 12Х18Н9Т STEEL BY NON-VACUUM ELECTRON BEAM PROCCESSING Loskutnikova V.V. , Master’s Degree student, e-mail: varvara.laskutnikova@yandex.ru Bushueva E.G. , Post-graduate Student, e-mail: dusias@mail.ru Tuyrin A.G. , Ph.D. (Engineering), e-mail: a.tuyrin@nstu.ru Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russian Federation Abstract The NbC wear-resistance coatings on 12Х18Н9Т steel produced by non-vacuum electron beam cladding with niobium carbide are studied in the paper. The main process parameter determining the thickness, structure, and mechanical properties of the hardened layer was the electron-beam current. As the beam current was increased from 22 to 24 mA. Hardness increased from 4.5 to 8 GPa. In friction tests against fixed abrasive particles, the wear-resistance of the cladding layers was 1.84 times higher than the base material specimens. The optical and electron microscopy of the composite coatings microstructure showed that niobium carbide reinforcing particles are evolved during the process. The coating thickness is about 3 mm. The microhardness test as well as wear resistance test of materials under conditions of loose abrasive particles are conducted. The microhardness of the coating is 3 times higher than the base material. It is established that the precipitation of reinforcing particles improves the tribological properties of the composite coatings. Keywords 12Х18Н9Т steel, niobium carbide, electron beam cladding, wear resistance.