Investigation of the hardness and wear resistance of working sections of machines hardened by vibroarc surfacing using cermet materials

Abstract

The results of investigations of the hardness and wear resistance of the working sections of machines, hardened using cermet materials in the form of paste, are presented. The optimum composition of the paste which greatly increases the service life of the working sections of the machines is determined.In the cultivation and the service of machines, the working sections are subjected to rapid wear as a result of the effect of abrasive particles, the cutting surfaces are blunted, and the shape, profile and working dimensions are greatly changed. Consequently, the quality of field operations is disrupted, the performance of these operations is delayed, the idle time of equipment is extended, the consumption of fuel and lubrication materials is increased and the amount of finished products is decreased [1 -3]. Therefore, the development and application of technologies capable of increasing the wear resistance of the working sections of machines is an important task and the solution of this task is of considerable importance in many areas of production.At present, a promising hardening method, which greatly increases the hardness and wear resistance of the cutting edges of the working sections of the machines, is vibroarc hardening (VAH) with cermet materials [4 -6]. In VAH, a cermet material in the form of paste is deposited on the hardened surface of the working section and burning of the direct arc results in both thermal diffusion hardening of the surface with alloying elements, including the composition of the cermet material, and VAH of the cermet coatings. A distinguishing feature of VAH is the absence of any significant heat input into the component during hardening.The cermet material developed in this study consists of a steel matrix (surfacing powder) with inclusions of alumina Al 2 O 3 , silicon SiO 3 , boron carbide B 4 C, refined to the nanosized state, and also alloying elements: nitrogen, present in the ammonium nitrate NH 4 NO 3 , and aluminium [5 -7]. Aluminium is used for deoxidation of iron and also for the formation of the ceramic phase by transformation to the aluminium oxide Al 2 O 3 and, in subsequent melting, to corundum. Corundum occupies position 9 in the mineralogical table of hardness, which is very close to the hardness of diamond. The matrix is an impact resistant, sustaining and composite frame of the cermet material. Therefore, the matrix material is produced from steelsurfacing powders with high hardness and abrasive resistance, for example PG-10N-01, PR-N70Kh17S3R4 and PG-SR4. To ensure the high impact toughness of the hardened surfaces, the content of the matrix material in the composition of the cermet material should not be less than 50%.Preliminary investigation showed that each of the components of the cermet material has a strong effect on the efficiency of hardening of the working sections of the machines. Therefore, investigations were carried out to determine the effect of the components of the cermet material on the hardness and wear resistance of hardened surfaces in orde...

Theoretical background for the creation of wear-resistant coatings at the carbo-vibro-arc hardening

“…During formation of metal-ceramic coatings by the CVAH method a multicomponent paste was used containing RI ɉɊ-ɇɏɋɊ SRZGHU, 30% of boron carbide, and the restcryolite. In connection with the widespread use of aqueous PVA glue solution in the CVAH coating formation processes, this solution was selected as a binder in these studies [8,9,11,12,14].…”

“…Then, after the paste polymerization, it is melted using a vibrating carbon electrode. The process of metal-ceramic coating formation with high physical and mechanical properties and tribotechnical characteristics is realized due to electric arc combustion [8][9][10][11][12][13][14].…”

Technology of Reconditioning with Hardening of Working Elements of Construction and Road Machines by Composite Coatings

“…The Carbo Vibro Arc Hardening method (CVAH) is a modern method of formation of the composite metal ceramic coatings, which to a large extent is deprived from the above mentioned disadvantages and which permits to increase sufficiently the wear resistance of the working elements cutting surfaces [7][8][9][10][11][12]. At the CVAH the metal ceramic paste, containing the metal matrix, hardening ceramic components and the material activating the arcing process (cryolite), is applied on the harden cutting surface.…”

Increasing of Corrosion Resistance for Metal Products of Livestock Premises

“…The main reason for metal products resource underutilization of livestock equipment and premises is aggressive environments impact on them formed by the animals vital products that lead to an increased corrosion rate of these objects. At the same time, failed equipment and metal products must be replaced with new ones or a long and laborious restoration of their working capacity is required [1,2,3].…”