Based on an overview of methods for hardening and restoring parts of agricultural machines, it has been found that the methods currently used are highly labour intensive and are not well suited for hardening the cutting edge of tillage machine discs. A method of electromechanical hardening of ploughshare discs due to simultaneous thermal action and plastic deformation is disclosed. Electromechanical hardening modes are justified on the example of standard cylindrical samples. The developed technique contains the following stages: determining the steel grade of a part; planning of the experiment based on the plan of the full two-factor three-level experiment with selection of influences and response function; experimental hardening of laboratory samples at the installation; microstructural analysis of hardened samples; numerical processing of experiment results. Based on the optical emission analysis, it was found that the samples are made of steel 65G. The factors of influence are: current strength X1(Ir) = 800...1200 A on the reinforcing tool in the form of a roller and the pressing force X2(Fk) = 100...300 N of the tool to the part. The hardness of the surface layer Y(HRC) is adopted as the response function. Microstructural analysis showed that a layer consisting of several zones was formed on the hardened surface of the sample: white, light non-flowing and dark martensitic, passing into the ferrite-pearlite structure of the base. On the basis of multiple regression analysis, an empirical mathematical model is obtained and its graphical interpretation in the studied area of factors values is given. According to the criterion of providing wear resistance of working edges of disks, maximum hardness is achieved at current strength X1(Ir) = 1060 A and force X2(Fk) = 210 N in the contact zone. Developed technique and tested modes of electromechanical hardening are suitable for development of process of hardening of disk ploughshares of grain-grass seeders.

Ensuring failure-free operation of agricultural machinery in seasonal operation conditions is based on a maintenance system including diagnostics. A promising method of diagnosing the technical condition of mechanical transmission units is contactless thermometry based on measuring the intensity of infrared radiation of friction pairs. The purpose of the work is to verify the thermometric diagnostic method for mechanical transmission units of agricultural machinery. The results of experimental development of technology of thermometric nondestructive testing of the cardan joint of ZAFFRANI 940N reaper drive CLAAS TUCANO 570 grain harvester are presented in the work. The method of conducting the experiment included monitoring the temperature of parts and ambient air, the dynamic parameters of the reaper drive and the level of solar radiation. In order to implement the system approach, evaluation of the thermal state of the object of research was carried out at three hierarchical levels. The first level is represented by an analytical equation for determining the temperature in the friction zone. The second hierarchical level is implemented using CAE-technology, which makes it possible to establish the relationship of temperature in the friction zone and diagnostic temperature on the surface of the part. The influence of external heating factors at the third hierarchical level is due to solar radiation, which causes heating of the surfaces of the parts. To take this factor into account and compensate for the measured temperature values, a mathematical model of the thermal balance for the studied unit was developed, which includes thermal energy from solar radiation and energy supplied to the environment through convection and radiation. A summary of the results of the study confirms the effectiveness of thermometric nondestructive testing for mechanical transmission units using the example of bearing assemblies of the cardan joint of the reaper drive.