Pump elements recondition by electrolytic chromium plating

Improving the efficiency of maintenance production in agriculture closely connected to the creation and implementation of such methods of repair and recondition of elements that improve the physicomechanical and service properties of wear joint assemblies.The presence of a nitrided case on the surface of elements lays the groundwork for obtaining a complex covering based on chromium nitrides. Electrolytic chromium plating is one of the ways to recondition elements that increase the service life and machines reliability, and reduce maintenance cost. However, the widespread adoption of chromium plating for the recondition of worn elements is hold back by the low productivity of the process. Therefore, the intensification of chromium plating in reconditioning worn-out machine elements is an urgent problem. It is advisable to recondition critical parts subjecting to abrasive wear, for example, precision vapors of fuel injection equipment, with chromium plating. However, the low productivity and high-energy consumption of the process require the improvement of the electrolyte in order to increase the current output of chromium and the permissible cathode density. The article describes a method for improving the quality of an electrolyte, a method for increasing its versatility, namely the supplementation of various organic additives and complexing substances into it.

Results of stand and operational tests of high pressure fuel pump with plunger pairs recovered by nanocomposition chromination

The article presents the technology of restoration and hardening of plunger pairs of fuel injection pumps by nanocomposite electrolytic chrome plating, as well as the results of bench and performance tests of fuel injection pumps for the YaMZ-238ND3 diesel engine. According to the test results, the reduction of the starting cyclic fuel supply for a pump with plunger pairs, restored and strengthened by nanocomposite electrolytic chromium plating is 1.1–1.38 times less than that of a pump with plunger pairs recovered and hardened by base chromium plating and 1.4–1.8 times less than the TNVD with serial plunger pairs.

STRUCTURAL PECULIARITIES OF THE PROCESS OF ELECTROLYTIC CHROMIUM PLATING IN RESTORATION OF WORN PARTS

Processes occurring at the metal-electrolyte interface in chrome plating of parts with an inhomogeneous structure have been considered from the standpoint of the band theory of semiconductors. Similarity of processes in the systems metal - semiconductor and metal - electrolyte has been established. A technique for estimating the quality of surface preparation of worn parts for electrolytic chromium plating based on the results of measuring the spread of thermal EMF values has been validated.

CONTROL OF THE SURFACE CONDITION OF STEEL PARTS RESTORED BY ELECTROLYTIC CHROMIUM-PLATING IN THE PROCESS OF REPAIR

The article deals with peculiarities of restoration of steel parts by electrolytic chromium-plating depending on structural heterogeneity of worn surfaces. The possibility of assessing the quality of surface preparation for the process of chromium-plating by the results of measuring the thermal EMF in local areas of the restored surface is shown. A technological route of quality control in restoration of heavily loaded parts of gas turbine engines implemented in working environment is proposed.