Methodology and results of the study of physical, mechanical and tribological characteristics of nitrided inner surfaces of long holes

Abstract

Created control device physico-chemical and tribological characteristics of nitrided internal surfaces of long holes, which is a hollow pipe with radial holes made at a certain distance from its ends to ensure the ratio of the height of the center of the sample to the internal diameter of the pipe from 0 to 10 or more, which differs in that the height of the samples simulates the depth of the longitudinal holes, and the samples themselves to facilitate their fixation and to ensure the absence of electric spark discharge near the ends, they are installed with a certain tension. At the same time, the length of the cylindrical sample is equal to the thickness of the pipe wall.Thus, each sample is nitrided from two ends, which makes it possible to nitride from the outside and from the middle of the model at almost the same temperature, as well as to compare the results of nitriding of two surfaces (external and internal). At the same time, the difference in conditions is only in the location of these surfaces - external or internal. All other factors that could affect the results of the modification are practically identical. However, nitriding in a glow discharge with a constant current supply does not ensure the treatment of the inner surface uniformly throughout the entire depth, and with significant ratios of length to diameter (more than 4), the inner surface of the hole remote from the ends is practically not nitrided. Therefore, a process technology and a device for quality control of anhydrous nitriding in glow discharge (BATR) of long holes with cyclically switched power supply of the gas discharge chamber have been developed.

Keywords

• long holes, cyclically switched discharge, wear resistance, dry friction