Дослідження ефективності комплексного іонного азотування для модифікації сталі
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Дата
2018
DOI
doi.org/10.30977/BUL.2219-5548.2018.82.0.13
Науковий ступінь
Рівень дисертації
Шифр та назва спеціальності
Рада захисту
Установа захисту
Науковий керівник
Члени комітету
Видавець
Харківський національний автомобільно-дорожній університет
Анотація
Надано експериментальні результати впливу процесу комплексного іонного азотування за різними режимами на глибину азотованого шару. Визначено структурні особливості поверхневих та приповерхневих шарів сталі та характер розподілу мікротвердості по перерізу деталі. Встановлено, що технологія комплексного іонного азотування для модифікації сталі за рахунок глибинного азотування є ефективною та заслуговує впровадження й розвитку.
The development of integrated ion nitriding technology is actual for industrial production. This method is in the development stage, especially for steels that are not classical for nitriding, for example, cheap and available steel 9XC for production. The goal of the research is to study the influence parameters of the process of low-temperature nitriding in plasma of a nonindependent low-pressure arc discharge on structure and properties of the surface and near-surface layers of punches from steel 9XC in combination with subsequent heat treatment. Results. The research solved the following tasks: 1. A metallographic analysis of 9XС steel samples after complex ion nitriding is carried out, which includes nitriding and subsequent heat treatment (quenching and tempering at various temperatures). 2. Measured microhardness of surface and near-surface layers in depth. 3. Phase analysis is done. 4. Determined depths of nitrogen-hardened layers and their morphological features. 5. Conclusions are made on the practical use of integrated ion nitriding technology. Practical value. For hardening punches of steel 9XC method of complex processing are proposed and tested in the work. It includes nitriding in a vacuum gas discharge before quenching and tempering. At the same time, the process of diffusion of nitrogen atoms is significantly accelerated (since nitrogen atoms more easily penetrate nonhardened steel), which leads to an increase in the depth to the penetration of nitrogen atoms and a change in structure and hardness. It was established that, by properties, the impact area is divided into a surface layer (with a thickness of about 200 μm) with a lower hardness and a deeper working layer with a higher hardness. The size of the strengthening zone is 560–920 μm. At the same time, increased hardness compared to the main structure without nitriding is remained at a depth exceeding 2000 μm. The surface layer of parts with low hardness must be mechanically processed to obtain the required dimensional accuracy and roughness. The surface hardness of the punches made of steel 9XC after such treatment is at the level of 6600 MPa. The phase composition of the nitrated layer with high hardness consists of the lower nitride of Fe4N and a solution of nitrogen in α-Fe. The results obtained are relevant for steel with a low tempering temperature.
The development of integrated ion nitriding technology is actual for industrial production. This method is in the development stage, especially for steels that are not classical for nitriding, for example, cheap and available steel 9XC for production. The goal of the research is to study the influence parameters of the process of low-temperature nitriding in plasma of a nonindependent low-pressure arc discharge on structure and properties of the surface and near-surface layers of punches from steel 9XC in combination with subsequent heat treatment. Results. The research solved the following tasks: 1. A metallographic analysis of 9XС steel samples after complex ion nitriding is carried out, which includes nitriding and subsequent heat treatment (quenching and tempering at various temperatures). 2. Measured microhardness of surface and near-surface layers in depth. 3. Phase analysis is done. 4. Determined depths of nitrogen-hardened layers and their morphological features. 5. Conclusions are made on the practical use of integrated ion nitriding technology. Practical value. For hardening punches of steel 9XC method of complex processing are proposed and tested in the work. It includes nitriding in a vacuum gas discharge before quenching and tempering. At the same time, the process of diffusion of nitrogen atoms is significantly accelerated (since nitrogen atoms more easily penetrate nonhardened steel), which leads to an increase in the depth to the penetration of nitrogen atoms and a change in structure and hardness. It was established that, by properties, the impact area is divided into a surface layer (with a thickness of about 200 μm) with a lower hardness and a deeper working layer with a higher hardness. The size of the strengthening zone is 560–920 μm. At the same time, increased hardness compared to the main structure without nitriding is remained at a depth exceeding 2000 μm. The surface layer of parts with low hardness must be mechanically processed to obtain the required dimensional accuracy and roughness. The surface hardness of the punches made of steel 9XC after such treatment is at the level of 6600 MPa. The phase composition of the nitrated layer with high hardness consists of the lower nitride of Fe4N and a solution of nitrogen in α-Fe. The results obtained are relevant for steel with a low tempering temperature.
Опис
Ключові слова
дифузія, глибина зміцнення, твердість, дифракційні спектри, машинобудування, зносостійкість, ion nitriding, complex processing, diffusion, depth of action, hardness, diffraction spectra
Бібліографічний опис
Соболь О. В. Дослідження ефективності комплексного іонного азотування для модифікації сталі / О. В. Соболь, С. М. Шевченко, Т. О. Протасенко // Вісник Харківського національного автомобільно-дорожнього університету : зб. наук. пр. – Харків : ХНАДУ, 2018. – Вип. 82. – С. 13-19.