INCREASE DURABILITY AND RELIABILITY OF CENTRIFUGAL SEPARATORS BY USING NEW MATERIALS

Abstract

The urgent task of increasing the durability and reliability of centrifugal separators under the conditions of corrosive erosion of treated media with a high content of chlorine ions and abrasive inclusions predetermined the transition to the manufacture of rotor parts from corrosionresistant, high-plastic steels of the austenitic and austenitic-ferrite class instead of the previously used high-strength and low-elastic steel martensitic class. The use of highly ductile corrosion-resistant steels with high fracture toughness characteristics eliminates the possibility of brittle fracture of rotors. However, these steels have a low yield strength, which makes it necessary to conduct hardening rotors for highly loaded body parts in the field of centrifugal forces. Hardening provides elastic operation of rotor parts during operation, creates fields of residual stresses that partially compensate for stresses arising in the operational mode. In this work, the stress-strain state and the bearing capacity of the rotor of a separator of a self-unloading type with a diameter of 500 mm, made of parts that have passed the hardening cycle, are investigated. Three variants of the rotor of the same design were investigated, differing in the materials of the body parts, for which austenitic steel grades 06X17H13M3-VD, ALIII-23-43-02 and austenitic-ferritic grades 10X26H5M, ALIII-23-24 were used. The stress-strain state of the rotor was investigated by the numerical finite element method for an axisymmetric problem. When choosing a design scheme, the following assumptions are made: the rotor is an axisymmetric design with an axisymmetric load; initial stresses are not taken into account; the load from the influence of the medium being treated is perceived by the rotor body parts (excluding the internal piston). The boundary conditions for the rotor are determined based on the analysis of the interaction of the hub with the shaft (the landing of the rotor on the shaft is carried out with the hub fixed in the axial direction). During the loading process, the residual deformation was determined by steps by the strain gauging method, and the diameters of the parts were also measured with a micrometer with an accuracy of ± 0.01 mm. Strain gages were glued at the circuits of the concentrators: holes for the cover stopper relative to the base, unloading windows, holes in the tightening rings, as well as on the ends of the base and the tightening ring. Thus, based on the results of the study, it can be recommended for the manufacture of rotors of separators of steel of austenitic-ferrite class, providing the necessary safety margins of structures.