Foreign cold-rolled stainless steel cold strip production equipment and technology
In recent years, the global cold-rolled stainless steel broadband market has continued to grow, and the output has also increased significantly. It is expected that by 2020, the annual growth rate of stainless steel broadband production will reach 4%, that of China will exceed 5%, and the industrialized countries will also reach 3%.
At the same time, the difference between its cost and selling price has dropped from US$1,300 10 years ago to US$900, and will further fall to US$500 to US$600 in the next 10 years. For this reason, equipment manufacturers have been striving to develop flexible and efficient production equipment to increase productivity and reduce costs.
The rolling-annealing-pickling combined production line is the stainless steel cold strip production technology researched and developed under this situation. Since the development of this combined production line in the mid-1990s, there have been three types of production lines, which are briefly introduced below.
The first type of production line was first put into production by the American J&L Special Steel Company, and then the French Ugina Company also installed one. The production line is a direct combination of the rolling-annealing-pickling process. The raw material is a hot-rolled strip without pickling, and the final product is strip steel with a surface grade of 2B. The production equipment includes scale crusher and shot blasting equipment, pickling equipment at the entrance of the rolling mill, electrolysis, and mixed pickling equipment, and surface smoothing machine.
The second type of production is the newly installed production line of Finland’s Avista/Outokumpu and is currently undergoing trial production. The production line has the latest technology and can maximize production capacity. The raw material is the No.1 surface grade plate and strip, using the rolling and scale breaking technology developed by Deutsche Mark, which is the first time that this technology has been used in industrial production. The equipment of this production line includes a rolling mill, annealing furnace, scale breaking machine and shot blasting machine, electrolysis and mixed acid pickling equipment, leveling machine and tension leveler, and the surface grade of the finished product is 2B.
The third type of production line was developed by the German Mark Demag company. The raw material is hot-rolled strip steel with a surface grade of 2B after pickling and heat treatment. Taiwan’s Yieh United Group has ordered a production line using this technology. The equipment includes a rolling mill, annealing equipment, electric angle, and mixed acid pickling equipment, and surface smoothing machine.
The production line has high requirements for raw materials and is extremely susceptible to raw material defects; in addition, compared with traditional processes, it has lower flexibility in terms of steel grades and dimensions. The advantage is that all defects of the hot-rolled strip can be detected in the previous process, and the cost per ton of steel is reduced by 25 Euros compared with the traditional process. If the CSP process is used to produce stainless steel, cold-rolled thin strips with a thickness of 0.6mm can be produced.
The three types of production lines are developed for different markets, so although the market position of each process is limited, there are a large number of products.