International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In this this research work, the results of investigation corrosion condition of the steel pipe system for the heated water transportation and distribution after long years of exploitation are presented. The analysis was performed on the pipe segments after their removing i.e. cutting. Thirty segments were taken for inspection. The outer and inner surface of the pipes was inspected. Plan for inspection was prepared basing of the literature revue and personal experience. All specimens were visually inspected. For the investigations of pitting corrosion measuring of depth of pits was done. Performed investigations confirmed that general corrosion, uniform and no uniform is represented on the pipe from the outer side. From the inner side are presented different types of pitting: narrow, shallow, and elliptical and corrosion under layer. Performed investigation confirmed that the most dangerous for the piping systems is corrosion on the outer sides of the pipes which their perforation. Measurement of the pits deepness showed that pitting corrosion is not so danger because pits deepness is in the range between 0.18-1.24 mm which is negligible compared with the pipes wall thickness.

This practical research work is devoted to the adaptation of technology for ion plasma nitriding of mechanical parts (pins and gears). Formerly these parts were inductive hardened, and requirement of the purchaser was to replace inductive hardening technology with the chemical-heat treatment i.e. ion plasma nit riding.

Procedure for ion plasma nitriding of pin hammers and gears made of 4M2CrMo4 steel was described. Starting from the heat treatment of the parts, their cleaning and charging of the parts in the chamber. Description of the chamber and complete installation for nitride in is described. Experimental nitriding parameters are given too. Finally, accuracy of obtained results was checked using hardness measured of nitrided parts. Hardness values were in accordance with purchaser requirement.