The structural stability of continuous casting roller tables, a component of steel machinery, directly impacts the safety and continuity of continuous casting production when operating in high-temperature environments. Because continuous casting roller tables endure prolonged, cyclical contact with scorching hot billets, their surface temperatures undergo drastic alternating hot and cold cycles. Simultaneously, the internal cooling system continuously removes heat. This complex thermal stress environment places stringent demands on the roller table's structural design, material selection, and cooling control. To ensure its stability at high temperatures, a comprehensive protection system must be constructed, encompassing material performance optimization, cooling system design, thermal stress control, structural strength enhancement, surface protection reinforcement, dynamic monitoring and maintenance, and process parameter matching.
Material performance is fundamental to the high-temperature stability of continuous casting roller tables. Continuous casting roller tables require the use of special alloy materials with excellent high-temperature properties. These materials must maintain high yield strength at high temperatures to resist plastic deformation caused by billet extrusion; they must also possess resistance to high-temperature oxidation to prevent the surface oxide layer from peeling off and accelerating wear; furthermore, the materials must combine red hardness with resistance to thermal fatigue crack propagation to prevent microcracks from developing and propagating to failure due to alternating hot and cold temperatures. For example, adding elements such as molybdenum and vanadium to certain high-chromium alloys to form stable carbides can significantly improve the material's hardness and toughness at high temperatures, extending the service life of the roller table.
Precise design of the cooling system is crucial for controlling the thermal stress of the roller table. Continuous casting roller tables typically employ a combination of internal water cooling and external spray cooling. Internal cooling water flows through the roller body to remove core heat, while external sprays rapidly reduce the roller surface temperature. The layout of the cooling water channels needs to be optimized based on the stress distribution of the roller table. For example, adding cooling water nozzles in stress concentration areas can enhance localized cooling. Simultaneously, the cooling water flow rate and temperature must be controlled to prevent a sudden drop in roller table surface temperature due to excessive water flow, which could exacerbate thermal stress fluctuations. Furthermore, the cooling water must be strictly filtered to prevent impurities from clogging the water channels and affecting cooling efficiency.
Thermal stress control requires structural optimization and process coordination. Continuous casting roller tables generate asymmetric, periodically varying thermal stresses at high temperatures. If the structural design is unreasonable, stress concentration can easily lead to cracks. To address this, a three-section roll structure can be adopted, with segmented design to disperse stress; alternatively, the roll table can be pre-stressed to utilize mechanical force to offset some thermal stress and reduce the amplitude of cyclic stress. At the process level, it is necessary to stabilize the continuous casting speed to avoid billet temperature fluctuations caused by speed changes, which would affect the roll table's thermal load; simultaneously, billet thickness and temperature uniformity must be controlled to reduce the risk of localized overheating of the roll table.
Surface protection and strengthening are crucial for improving the roll table's wear resistance. In high-temperature environments, the roll table surface is prone to steel adhesion to the billet, leading to increased surface roughness and accelerated wear. Spraying an anti-adhesion coating such as tungsten carbide onto the roll table surface can form a dense protective layer, reducing high-temperature steel adhesion and maintaining surface integrity; simultaneously, the coating must be corrosion-resistant to prevent acidic substances in the cooling water from corroding the substrate. Furthermore, regular machining repair of the roll table surface can eliminate oxide layers and microcracks, restore surface precision, and extend service life.
Dynamic monitoring and maintenance are essential measures to ensure the stable operation of the roll table. By installing temperature sensors and stress monitoring devices at key locations on the roller table, real-time data on the roller table's temperature field and stress distribution can be acquired. This data, combined with analysis models, can predict potential failure risks. For example, when the roller table surface temperature exceeds a set threshold or abnormal fluctuations occur in stress concentration areas, the system can automatically trigger an alarm and adjust process parameters to prevent the fault from escalating. Simultaneously, a regular maintenance system must be established to clean and inspect the cooling system to ensure unobstructed water flow; non-destructive testing of the roller table surface should be performed to promptly detect and repair micro-cracks, preventing crack propagation and subsequent fracture.
Matching process parameters is the core aspect of optimizing the roller table's thermal load. In continuous casting production, parameters such as molten steel temperature, casting speed, and cooling intensity must be closely matched with the roller table's performance. For example, high-temperature molten steel requires tundish heating technology to compensate for temperature drops, ensuring stable temperatures upon entering the roller table; casting speed needs to be adjusted according to the steel grade characteristics and the roller table's cooling capacity to avoid exceeding the roller table's thermal load limits due to excessive casting speed; and cooling intensity needs to be dynamically adjusted based on the billet thickness and temperature gradient to maintain the roller table's thermal balance. Precise control of process parameters can significantly reduce the structural stress of the continuous casting roller table at high temperatures, thereby improving its stability.
Ensuring the structural stability of continuous casting roller tables in steel machinery under high-temperature environments requires comprehensive measures, including material performance optimization, cooling system design, thermal stress control, surface protection enhancement, dynamic monitoring and maintenance, and process parameter matching. By constructing a multi-dimensional assurance system, the service life of the roller table can be effectively extended, the failure rate reduced, and a solid foundation provided for the efficient and stable operation of continuous casting production.
