TECHNOLOGICAL PASSPORT STUDY PISTON AND CONNECTING ROD BARE MATERIAL AXIAL ROTARY PISTON PUMP

Abstract

A technological passport of the alloy steel material has been formed, from which a piston-connecting rod pair of an axial-rotor piston pump is made in the form of functions: flow curve, plasticity diagram, Bauschinger curve, calibration graph. Using the approximation of the neck contour by the Gaussian function at any moment of deformation of a cylindrical specimen in the supercritical region, the main parameters used in engineering calculations are related: the minimum diameter of the specimen, the current diameter of the specimen with a given coordinate, the relative (absolute) elongation and contraction with the parameters referred to the moment of rupture sample. In addition, the elongation and contraction of the sample after fracture are unambiguously associated. The approximation avoids the inconvenient and relatively expensive video filming for studying the history of deformation. It is shown that the effect of heat treatment on the mechanical properties of these steels is not the same for different stress state schemes. The tensile strengths of these steels are close as delivered. The plasticity characteristics of steel 30Kh3MFA exceed the plasticity of steel 38Kh2MYuA by 1.5 times. The flow curves of the steels under consideration have the following tendency: so the coefficient of approximation of the flow curve for 38Kh2MYuA steel in the delivery state exceeds its value in relation to steel 30Kh3MFA by 1.23 times. After heat treatment of these steels, the value of the approximation coefficient increases: for steel 38Kh2MYuA by 1.11 times, for steel 30Kh3MFA by 1.46 times. The results obtained make it possible to control the mechanics of the technological operation of rolling the piston-connecting rod pair and create a process control mechanism in order to prevent rejects during the rolling process, which manifests itself in the form of going beyond the tolerance field for the axial clearance of the piston-connecting rod pair, as well as destruction during rolling of the inner part of the piston.