- Medium and thick plates usually account for about 10% of the total steel production and are the basic raw materials for important infrastructure construction and large-scale engineering and heavy machinery manufacturing. Before China’s reform and opening up, the main force of the medium and thick plate mill is the small medium and thick plate mill with the equipment level and technical level of 2000 ~ 3000mm, which have a big gap with the international advanced level. Automatic thickness control and accelerated cooling, two of the most important basic technologies for thick plates, have achieved little results after several explorations.
After the reform and opening up, individual units introduced foreign technology to build the medium and thick plate mill. For example, the 3000 medium and heavy plate mill of Jiuquan Iron and Steel Company and the second-hand 4300 medium and heavy plate mill of Anshan Iron and Steel Company. Some units have introduced monomer technologies such as AGC. By the end of the 20th century, the construction of thick plates began to accelerate. On the one hand some units take into account China’s strong demand for wide plate on the basis of digestion and introduction and independent exploration to use their own strength to build plate rolling mill. For example, Shougang, in close cooperation with universities, research units, heavy machinery factories, electrical machinery factories and other units, designed the large-scale high-stiffness, high-precision 3500 medium and thick plate mill by itself, developed the basic technology of automatic thickness control technology, accelerated cooling technology, controlled rolling and controlled cooling technology, and began the road of independent integration and innovation of China’s large medium and thick plate mill. On the other hand, some units in the cooperative manufacturing method to introduce 3800 ~ 5500 extra-wide plate rolling mill, heavy straightener, shear and other heavy equipment, in addition to the introduction of basic control systems, such as thickness, width, temperature and other control systems, At the same time, the introduction of the relevant planar shape control (PVR), plate shape automatic control (CVC+, SMART CROWN), optimized shear control and other high-precision rolling technology and the corresponding automatic control system. The original medium and thick plate mill, most of the technical transformation, the use of domestic automatic thickness control, accelerated cooling technology, T MCP technology, improve the level of equipment installed and automatic control level, improve the quality and output of products, expand the specifications and varieties. Through the introduction of medium and thick plate heat treatment equipment technology and equipment, China has gradually mastered the design, manufacturing and production technology of high-level medium and thick plate heat treatment equipment. At present, it has been able to provide a complete set of wide-width, heavy-duty plate mill mechanical equipment and advanced high-precision rolling control system, as well as complete sets of production technology. In the process of the development of medium plate technology, medium plate controlled cooling technology has also experienced a tortuous development process. Before the reform and opening up, China’s rolling mill can be called the world’s most “dry” rolling mill control cooling technology has not made a major breakthrough. After the reform and opening up, some enterprises began to introduce accelerated cooling technology from abroad, such as ADCO vapor cooling technology introduced by Jiujiang Iron and Steel, DQ+ laminar flow ACC cooling technology of Baosteel and other units, and the MULPIC rapid cooling system introduced by Wugang in recent years, which can complete the two functions of rapid cooling (ACC) and direct quenching (DQ). However, on the basis of learning from foreign technology, more enterprises have cooperated with universities and research institutions and made use of China’s own strength to develop a variety of laminar cooling systems such as tube laminar flow, water pillow laminar flow and water curtain laminar flow, which to a certain extent provides the equipment foundation for the TMCP process and product development of various factories. At the same time, it also makes early preparations for the research and development of a new generation of cooling technology – ultra-fast cooling technology. In recent years, some research units have cooperated with enterprises to develop ultra-fast cooling equipment and a new generation of TMCP process, so that China’s post-rolling cooling technology and TMCP level have gradually reached the international advanced level.
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