Analysis of Technological Breakthroughs and Future Development Prospects of Pickling and Cold Tandem Rolling Mills

Technological Innovation and Automated Control of Cold Tandem Rolling Process Equipment  

When exploring the full picture of pickling and cold tandem rolling mill technology, we must mention the innovation of cold tandem rolling process equipment and the breakthroughs in high-precision automated control. The breakthroughs and development of these two core technologies have jointly driven China's technological progress in this field.  

Integration Technology and Development of PL-TCM Mills  

The integration technology of Pickling and Cold Tandem Rolling Combined Mills (PL-TCM Mills) is internationally recognized as a comprehensive technology characterized by system complexity, high technology intensity, and strict precision requirements. It involves multiple professional fields such as mill assembly, process engineering, mechanical engineering, and electrical, electronic, and automation systems, requiring profound comprehensive professional capabilities for support. Currently, there are very few top international companies with such integration capabilities, such as SMS Group (Germany) and Mitsubishi (Japan). However, after decades of technological accumulation, introduction, digestion, absorption, and innovative improvement, China has made remarkable progress in cold tandem rolling technology. Particularly in engineering design, equipment manufacturing, and independent integration of production mills, China has reached a new height.  

Evolution of Cold Tandem Rolling Production Technology  

With the diversification of demand for cold-rolled steel strips, their production technology has also undergone significant evolution. To meet the requirements of different grades, specifications, quality, and production scales, the production of cold-rolled steel strips has gradually shifted from single-sheet rolling to coil rolling, and further developed into fully continuous rolling technology and the application of combined pickling and rolling mills. Today, tandem rolling mills have become the main equipment for large-scale, high-efficiency production of high-quality cold-rolled thin steel strips.  

Although China started late in cold-rolled steel strip production, after decades of efforts, it has established various types of cold rolling mills and successfully achieved the production transition from low-carbon thin sheets to high-carbon steel, high-alloy steel, and stainless steel cold-rolled thin sheets. In recent years, with the introduction of new equipment and new processes, the technical level of China's cold-rolled steel strip production has been significantly improved. At present, the technology of Pickling and Cold Tandem Rolling Combined Mills (PL-TCM Mills) has become mature in China, laying a solid foundation for further development.  

Technical Advantages and Applications of PL-TCM Mills  

By closely integrating pickling and cold tandem rolling for continuous production, PL-TCM Mills not only meet the requirements for steel strip thickness, flatness, and surface quality in an economical and efficient manner but also significantly improve the production capacity and output of rolling mills. In addition, this technology eliminates the need for steel strip threading and tail-throwing operations, thereby saving production costs, reducing the cutting loss of the head and tail of the steel strip, and further increasing the total output.  

To realize the smooth combination of different mills and form a high-efficiency continuous production line, the key lies in ensuring that the average metal flow rate per second of the steel strip in each section of the process line remains consistent. The pickling and cold rolling combined mill precisely meets this condition. The turbulent pickling technology and mechanical pre-descaling equipment adopted by it greatly improve the pickling quality and production efficiency. Meanwhile, the application of advanced technologies such as 6-high UCM or UCMW rolling mills, hydraulic roll shifting, positive and negative roll bending, CVC (Continuously Variable Crown) technology, backup roll crown control technology, hydraulic screw down, segmented roll cooling, and high-precision steel strip thickness and flatness detection systems ensures that the shape, thickness, and surface quality of cold-rolled products meet high standards.  

Compared with fully continuous cold rolling mills and conventional cold rolling mills, PL-TCM Mills exhibit higher production capacity, can produce high-quality cold-rolled steel strips, and have significant advantages such as lower investment, higher yield, better economic benefits, mature process technology, and stable equipment performance.  

Computer Control System of Cold Tandem Rolling Mills  

At present, China has made significant progress in the equipment and computer control systems of steel strip cold tandem rolling production lines, and has introduced the world's advanced core technologies for cold-rolled steel strip production. However, the core control technology of cold tandem rolling is still mastered by a few companies such as SMS Group (Germany) and Mitsubishi Hitachi (Japan), forming technical barriers in the industry. These companies often use a "black box" approach in the introduced systems to protect their core technologies, which limits the optimization of new functions, the development of new products, and system upgrading and transformation.  

Process Automation Control System  

The process control system of pickling and cold tandem rolling mills plays a crucial role. Its core task is to provide accurate load distribution and rolling setting parameters for the basic automation system of the rolling mill, and continuously optimize the model through adaptive and self-learning technologies. In addition, the system is also responsible for various model calculations, such as rolling force, forward slip, and deformation resistance, to ensure the production quality of the steel strip and the efficient operation of the equipment.  

Basic Automation Control System  

The basic automation system mainly controls electromechanical equipment, hydraulic systems, and related instruments. Internationally, several well-known companies such as GE (USA), Siemens (Germany), Mitsubishi-Hitachi (Japan), and ALSTOM (France) provide computer control systems for cold tandem rolling. These systems all adopt high-speed microprocessors for process control, sequence control, and auxiliary control of steel strip production, and support multi-machine collaborative work.  

Process Lubrication Technology and Tracking Function  

In the cold rolling process, emulsion plays a vital role. It not only lubricates the roll gap to reduce friction and wear but also cools the rolls and steel strips to prevent overheating. At the same time, the emulsion can effectively prevent the finished products from rusting, and through its flushing effect, the iron powder and other impurities generated during the rolling process are flushed into the collection tank, maintaining the cleanliness of production.  

The basic automation system of the cold tandem rolling production mill is equipped with a tracking function. This function mainly tracks the steel strip in real-time based on the characteristic points of the steel strip, such as the strip head, strip tail, weld seam, start and end positions of the wedge section, and start and end positions of defects. Its core goal is to periodically display the operation status of the steel strip on the rolling line and execute necessary operation switches.  

At present, in the domestic cold rolling field, some quality indicators still cannot fully meet the needs of high-end customers, and there is still a gap with the international advanced level in some technical indicators, especially in surface quality control and precision rolling technology, which require further research, development, and improvement. To meet the continuous needs of product development, we should focus on developing new equipment, optimizing process flows, and introducing innovative characteristic functions. At the same time, we should strengthen the independent research and development capabilities of automated detection instruments and controllers, further improve the application level of process optimization and intelligent algorithms, and realize intelligent and precise control of the manufacturing process. In the fierce market competition, the continuous research and development of cold rolling technology will become a key driving force for improving product quality and reducing production costs.