HARDENING OF THE ELECTRODESIEGED IRON CHEMICAL HEAT TREATMENT

• Main Authors: V. I. Serebrovskii, R. I. Safronov, B. S. Blinkov, M. V. Zhuravlev
• Format: Article
• Language: Russian
• Published: Voronezh state university of engineering technologies 2015-07-01
• Series: Vestnik Voronežskogo Gosudarstvennogo Universiteta Inženernyh Tehnologij
• Subjects: nitrocarburizing; fatigue strength; snooty-bone; electroplating; hardening of parts
• Online Access: https://www.vestnik-vsuet.ru/vguit/article/view/632

Summary. Currently in the repair and manufacture at the stage of recovery of steel parts, widely used special coatings formed by electrolytic effects on ferrous ions. This technique offers high performance, ease of implementation, low cost of technological equipment and materials used, as well as easy automation of the process. However, this method has several disadvantages: low fatigue strength of reconditioned parts, insufficiently strong grip of the iron coating to the substrate, particularly in alloy steels, insufficient wear resistance. For the purpose of increasing durability and wear resistance of parts, restored through electrochemical action, it is proposed to use chemical-heat treatment, consisting in the application of carbonitriding. Investigated the efficacy of different modes of carbonitriding in the highly carburizing paste-and their influence on the structure and properties of iron plating. It is established that the nitrocarburizing both low and high temperatures repeatedly (6-7.5 times) increases the microhardness of the coatings. The highest hardness is obtained by low-temperature carbonitriding with direct quenching in water. Conducting the carbonitriding process at low temperatures (650 °C), significantly increases the hardness of the iron coatings, increasing the limit of its fluidity, a and also greatly increases its endurance limit. Nitrocarburized fatigue strength of samples with iron precipitation on the surface, as shown by our studies, not only higher strength of the same samples without carbonitriding (more than 2 times), but higher than the fatigue strength of the base metal without coatings. Raising the temperature of the carbonitriding did not increase the hardness of electrolytic iron. Developed a rational technology of hardening of steel parts, re-chain iron fortification. Selected optimum conditions for carbonitriding hardening restored iron fortification, with the purpose of increasing durability of machine parts Optimal process temperature re-benching of the process of carbonitriding in which is possible to obtain maximum fatigue strength and wear resistance from the restored detail, is the process of carbonitriding at 650°C, followed by quenching and tempering at 150 °C.