SELECTION OF METHOD FOR RESTORATION OF PARTS

The paper contains definitions for a process and a methodology for restoration of parts on the basis of the analysis of the known methods and their selection. Geometric parameters and operational properties that should be provided for restoration of parts have been determined in the paper. A process for selection of the required method for restoration parts has been improved and it makes it possible to synthesize an optimal process of the restoration according to a criterion of industrial resource consumption with due account of quality, productivity and security limits. A justification on measures that meet the required limits has been presented in the paper. The paper shows a direction of technical solutions that ensure complete use of residual life of repair fund parts. These solutions can be achieved through close application of all repair sizes of work-pieces with revision of their values, uniform removal of the allowance while cutting the work-pieces at optimum locating, application of coating processes only in technically justified cases, application of straightening with thermal fixing of its results or all-around compression of deformable elements. The paper proposes to limit a number of overhauls for the units together with restoration of basic and fundamental parts by two repairs for the whole period of their lifetime. Number of shaft journal building-up should be limited by one building-up operation throughout the whole life cycle of the part with the purpose to preserve its length within the prescribed limits. It has been recommended to expand an application area of volumetric plastic deformation of material in the form of thermoplastic distribution or reduction of repair work-pieces representing class of rotation bodies with holes that ensures an allowance to machine external and internal surfaces for nominal dimensions without coating. A structure of the coating material with fine inclusions of carbides or nitrides of metals and preferred orientation of structural components perpendicular to the restored surface under the influence of heat removal has been established in the paper. Due to surface plastic deformation the structure orientates fiber axis tangentially in the direction of relative sliding that inhibits growth of fatigue radially oriented cracks.