The core technology system of medium-thick plate roller quenching machines includes the nozzle system and its optimized design. The key lies in developing a quenching water spray system with high-intensity cooling capacity and uniform cooling medium distribution. Structures with independent intellectual property rights, such as ultra-wide integral slit nozzles and embedded multi-row inclined high-density circular hole nozzles, have been developed. These structures aim to meet the high uniformity quenching requirements within a cooling rate range of 1.5-300℃/s.
To establish a quantitative relationship between cooling medium pressure, flow rate, and plate cooling intensity, an impact heat transfer mathematical model for high- and low-pressure continuous quenching technology has been developed. This model is a crucial basis for process parameter design and high-precision control.
Plate shape control during the quenching process is a key technical challenge. To achieve steel plate flatness control, flow rate zoning control technology in the width direction of the steel plate, symmetrical cooling control technology on the upper and lower surfaces in the thickness direction of the steel plate, and technology to reduce internal stress through continuous quenching in high- and low-pressure quenching zones have been developed.
To protect the moving upper frame and ensure quenching uniformity, high-precision synchronization of multiple hydraulic cylinders during the lifting process is required. A control scheme based on a hydraulic synchronous motor and proportional valve compensation was developed, enabling rapid lifting of 14-18 hydraulic cylinders with a synchronization deviation of less than 3%.
The system employs a two-level control system: basic automation and process automation. Basic automation utilizes equipment such as a SIEMENS S7-400 PLC to automatically set and control process parameters such as roll gap, water flow, and roll speed, achieving fully automated control of the quenching process and prediction of microstructure and properties.
The flexible cooling system features flow zoning along the length of the cooling zone, independent water supply to multiple chambers across the nozzle width, and special control for the beginning and end of the steel plate. The system integrates core technologies such as high-pressure, high-strength rapid cooling, wide-range cooling rate adjustment, and cooling path control, which can meet diverse quenching requirements from thin plates to ultra-thick plates (e.g., 300mm thick).