Оцінка експлуатаційних властивостей роликів зони вторинного охолодження МБЛЗ

• Date: 2025
• Main Authors: Hitko, O. Y., Ivanova, L. Kh., Bereza, O. Y.
• Format: Article
• Language: Ukrainian
• Published: Physico- Technological Institute of Metals and Alloys of the NAS of Ukraine 2025
• Subjects: ролик; сталь; макроструктура; експлуатація; міцність
• Online Access: https://momjournal.org.ua/index.php/mom/article/view/2025-1-4
• Journal Title: Metal Science and Treatment of Metals

The study is devoted to determining the operational characteristics of steel bimetallic rollers of a continuous billet casting machine in comparison with forged rollers. It is shown that the experimental rollers with a diameter of 270 mm fully worked out the overhaul period (70 days) together with serial forged rollers in one cassette. The durability of the rollers was 985 meltings. It is shown that the durability of bimetallic rollers increased by 7...10 times compared to forged rollers, and the ignition grid began to form only after 1000 meltings. The results of measuring the wear of the barrel diameters of the experimental and serial rollers showed that the maximum wear of the barrel of the experimental roller of the 20Х25Н19С2Л–20Л was 0.2 mm, the roller of the 17Х12МФЛ–20Л was 0.4 mm, and the serial forged rollers were 2.5...4.0 mm. The studies of the ignition resistance of experimental rollers of both designs were carried out on annular and longitudinal templates cut after their operation. In rollers of design 20Х25Н19С2Л-20Л, after 600 meltings, the formation of an ignition network began on their surface along the entire length of the barrel that was in contact with the ingot. By 1250 meltings, the depth of cracks in the working layer of these rollers was 7…9 mm, in some cases 12…17 mm. The inner layer was deformed or had radial cracks in the area of ​​the support pins. Analysis of the level of mechanical properties of steel 20Х25Н19С2Л after 1250 meltings showed a slight (by 9%) decrease in strength compared to the initial properties of the steel. In rollers of the 17Х12МФЛ-20Л, the ignition grid began to form only after 1000 heats and by 1250 heats it developed in the central section of the barrel with a length of 250…300 mm. The depth of the cracks did not exceed 1 mm. The strength level of 17Х12МФЛ steel did not change after 1250 heats. The macrostructure of the working and internal layers of the roller of the 17Х12МФЛ-20Л did not change after 1250 heats. When visually inspecting the surface defects of adhesion on the barrels of the experimental rollers, there were no adhesion defects. In the compared serial forged rollers, an ignition grid and striped adhesion were developed.