The hardness of working surface of ploughshares is very significant for their abrasive wear resistance. Knowing this mechanical property is especially important for manufacturing and hardening of ploughshares, since their wear is not uniform. In this regard, the research problems include studying of hardness distribution in the most loaded nose part of ploughshare, depending on its design and on welding reinforcement as a hardening method. Ploughshares after reinforcement and ploughshares in as-delivered condition after their taking out of service are submitted as objects of the research. Reinforcement included bead welding in the area of share point perpendicularly to the leading edge with the pitch of 30-40 mm. The validity of results was provided by measurement of four parts on each object of research. The total number of tested ploughshares was eight. Hardness was measured with a mobile hardness gage. Measurement results were recorded on Rockwell hardness scale (HRC) with subsequent conversion to Brinell hardness (HB). It is shown that for ploughshares without hardening, the hardness distribution in considered part has the non-uniform character, that is caused by the non-uniformity of processes of recrystallization because of unequal thickness of walls in separate volumes of a product. The hardness values of ploughshares in as-delivered condition are not high (230 HB maximum) and cannot provide the proper abrasive wear resistance. The lowered value of hardness (175 HB) is noted on the deepening part of a ploughshare. Application of welding reinforcement increases hardness (by 200 HB on the deepening part), that is connected with manifestation of heat hardening due to the formation of hardening structures. Traces of reinforcing beads make positive impact on the increase in hardness, which contributes to the growth of abrasive wear resistance.

The developed technique for determining the adhesive strength allows us to study both adhesive polymer composites and adhesive joints on the same device without the influence of the breaking force moment on the results obtained.

Among the details of the working bodies of soil-developing tools, cantilever-fixed structural elements occupy a certain place, which are operated under conditions of high-intensity abrasive wear. Known theoretical studies do not allow predicting the resource of cantilevered parts, taking into account the wear factor and the deformation ability of the material. Two tasks were theoretically solved in the work on determining the resource of a part until the moment when: 1 - the wear section becomes so thin that the transition area from the worn part to the non-worn part becomes more dangerous when bending than the cantilever fastening area; 2 - destruction will occur in the transition zone from the unworn to the worn area. Problem solving was carried out using the methods of the course "Strength of materials". The cantilever-fixed beam of variable section is taken as the design scheme. It was taken into account that the main parameter characterizing the strength of a bent beam is the magnitude of tensile strains that occur on its convex side. It was taken into account that the main parameter characterizing the strength of a bent beam is the magnitude of tensile strains that occur on its convex side. The conditions for the occurrence of the danger of destruction and the destruction itself in the section of the part, where the transition from the worn part to the non-worn part takes place, are determined by theoretical studies. The result of solving two problems was the derivation of formulas by which it is possible to predict the resource of a part in case of its local wear. A mathematical expression has been obtained that makes it possible to calculate the operating time of a locally worn cantilever-fixed part, when the width of the cross-section of the wear area decreases so much that the transition area to the unworn part becomes more dangerous than the cantilever fastening. A mathematical expression has been obtained that makes it possible to determine the resource of a structural element for the case when its destruction occurs at the point of transition from a worn area to a non-worn one.

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In spite of wide use of the polymer adhesive composite disperse materials in various industries, they aren’t in demand as materials for the restoration and strengthening of the friction surfaces of parts of tillage machines. The reason lies in the obscurity of their tribotechnical properties. First of all, these materials include the composites based on epoxy components filled with waste fractions of abrasive wheels. Therefore, the wear pattern during the testing time, as well as the effect of testing time on wear-out rate of the composite and of epoxy composition without filler have been investigated. The studies were of comparative nature and were carried out using an individual method. The content of this method is testing of 16 samples simultaneously in the same conditions at any time of the experiment. The epoxy composition (100 weight parts of ED-20 epoxy and 7 weight parts of hardener) and the composite comprising such epoxy composition and abrasive waste fractions of grinding wheels in the ratio of 30% to 70% respectively have been studied. The results of the experiments show that the dependence of wear and wear-out rate on testing time has a classic nature, identified previously in number of studies. The presence of dispersive component in composite in the form of waste fractions of abrasive wheels has a positive effect on reducing of its wear-out rate. It is established that the wear-out rate of composite is 1.5 times less than the wear-out rate of epoxy composition without filler, providing thereby the possibility of its use as an abrasion-resistant repair material for restoration of parts.