QUESTION OF APPLICABILITY OF THE CALCULATION ASSESSMENT METHOD OF RESISTANCE FOR DETAILS AFTER THERMAL DIFFUSION HARDENING

Abstract

Introduction.The article discusses the question of applicability of the calculation assessment method of resistance for details from gray cast iron after thermal diffusion hardening. The purpose of research is to check applicability of the calculated model for determination of intensity in case of the variable blanket hardness.Materials and methods.The model of intensity dependence on contact of two disks of friction gear is used in the research. Calculated determination of parameters is executed in two options: contact of the steel disk and disk from gray cast iron with the strengthened layer, and contact of the steel disk and disk from the tempered high-strength cast iron. Thus, roughness corresponding to the earned extra surface in contact zone is created. Experimental check of received results is carried out by means of specific work of abrasive wear definition for gray cast iron with the strengthened layer and the high-strength tempered cast iron.Results.As a result, it was established that the resistance of details from gray cast iron with the strengthened layer is comparable to high-strength cast iron after hardening. The results of experimental check prove the obtained calculations since the parameters values of resistance received would be well coordinated. Therefore, the possibility of the calculated resistant technique usage for such case could be considered as proved one and, therefore, it could be used at design calculations of the frictional units containing details from gray cast iron with the strengthened layer.Discussion and conclusions.The considered way of superficial hardening needs to be applied depending on features of operation on frictional unit. In such case, when the allowed values of wear change in wide limits (for example, brakes, coupling, etc.) it would be better not to subject a blanket to machining where the formation of optimum parameters of friction surfaces happened in natural way, or it would be necessary to delete an allowance. This suggests that the calculation method of the determination of layer resistance enables to define concrete values of an allowance which needs to be deleted.