Orenburg State University, Orenburg, Russia:

S. I. Bogodukhov, Professor at the Department of Materials Science and Technology, Doctor of Technical Sciences, Professor, e-mail: ogu@mailgate.ru
E. S. Kozik, Associate Professor at the Department of Materials Science and Technology, Candidate of Technical Sciences, e-mail: ele57670823@yandex.ru
E. V. Svidenko, Lecturer at the Department of Materials Science and Technology, Candidate of Technical Sciences, e-mail: tzvetkova.katia2016@yandex.ru

The authors of this paper performed ion implantation of hard alloys T14K8 and T15K6. According to the procedure, ions of any composition (e.g. ions of boron, nitrogen, titanium, tungsten, molybdenum and other elements) are implanted into the tool surface in a special unit at vacuum pressure of 1.33·10³ Pa. This leads to a double rise in the tool durability. They are commonly tools made of high-speed steel that are subjected to implantation. At the same time, this technique failed to find a broad application due to sophisticated equipment required and because of non-uniform saturation of the surface layer. Besides, more research into that process is needed. This paper looks at the effect of nitriding on the mechanical properties and performance of TK group hard alloys (i.e. dual-carbide tungsten-cobalt alloys): T15K6 and T14K8. The following specimens were used in the experimental study: 5×5×35 mm splines made of hard alloys T14K8 and T15K6, three-edged and triangular plates made of hard alloys T5K10 and T15K6 and four-edged plates made of hard alloy T15K6. The authors noted a slight increase in microhardness after 1 hour of nitriding: by 7% for T15K6 and by 11% for T14K8. The hardness of the hard alloy T14K8 rose by 7% (from 1,300 to 1,400 HV), while the hardness of the hard alloy T15K6 – by 9% (from 1,450 to 1,600 HV). Compared with the initial specimens, the strength of the specimens subjected to nitriding increased by 25% for T14K8 and by 36% for T15K6. Compared with the initial specimens, after nitriding the diamond-abrasive wear was half as much. Nitriding of the T14K8 and T15K6 grades of hard alloys is a long process taking around 9 hours, but it helps build a surface layer (2.5 μm deep for T14K8 and 2.2 μm deep for T15K6) that enhances the performance of hard alloys. Thus, the cutting wear drops 3 times.

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