Explaining the development direction of tinplate rolling process in China

Tinplate substrates are tinplates, which refers to cold-rolled low-carbon steel plates coated with commercial pure tin on both sides. It combines the strength and formability of steel with the corrosion resistance and solderability of tin. It is corrosion resistant, non-toxic, high strength, good ductility and beautiful appearance. It is widely used in food, beverage, chemical industry, etc. Coatings and other product packaging. From the world consumption structure of tinplates, tinplates consumed by food cans and beverage cans account for about 90% of total production. From the perspective of energy conservation, emission reduction and sustainable development, tinplate is a naturally degradable and environmentally friendly packaging material. With its preservation, light protection, robustness, and unique metal decorative charm, tinplate has become a widely used and important packaging variety.

Market demand "hope for" high-end production process

Cold rolling and leveling are key processes for producing tin plated substrates. In the research and development process abroad, the main application equipment is a multi-stand cold rolling mill and a complete unit. The research and development of single-stand tin-plating cold-rolling equipment and processes began in the 1930s. In 2002, overseas cold-rolling companies had a 68-inch single-stand four-high reversible cold rolling mill and a 68-inch single-rack four-high smooth mill. The annual output is about 300,000 tons. The single-stand reversing cold-rolling unit and single-stand leveling unit developed by Siemens rolled tinplates with an annual production capacity of 200,000 tons and 600,000 tons respectively.

Since the 1990s, China's economy has achieved rapid development, and a large number of multinational corporations have taken root in China. This has led to an ever-increasing demand for tinplate in China. The continuous expansion of the electronics industry, household appliances industry and other areas, so that the increasing demand for tinplate. In the past, the tin plate consumption in China mainly relied on imports. The insufficient production of tinplate severely restricted the development of China's economy. In order to solve the problem of localization of tinplates, in 1979, China introduced a set of 100,000-ton tinplate tinplate units from abroad and started the production of large tinplate units. In the early 1990s, Zhongyue Makou Industry Co., Ltd. of Zhongshan City, Guangdong Province, introduced two sets of electroplating tin units with a design capacity of 60,000 tons from South Korea, which were put into production in 1990 and 1994 respectively. Subsequently, many steel manufacturers have rushed to tinplate production-related technologies and equipment, and foreign investors have also begun investing in tin-plated production lines in China. So far, more than 10 sets of tin plating units have been put into operation in the country, with an annual production capacity of more than 1.7 million tons. Among them, Baosteel 1420 Cold Rolling Plant, which was fully put into operation in March 1998, is a tin-plating speciality production plant with a pickling-cold rolling combination unit, which specializes in the production of thin gauge cold-rolled coils. The main equipment includes dedicated continuous annealing of tin-plated substrates. The unit, the preparation unit and the two sets of tin-plating units with a capacity of 200,000 tons and a high-precision tinplate shearing unit have the production capacity of DI-plated tinplates. The current output has exceeded 1,500 tons. The factory can also produce thin, wide tin plate (0.28mm x 1162mm). In addition, a number of tin-plated narrow-band production plants have emerged in Wuxi, Jiangyin and Changzhou. By the year 2000, the production of tinplate in China has increased significantly, and some products have begun to export. However, high-end products still need a lot of imports, and key technologies are still relatively scarce. In 2003, the import volume reached 520,000 tons, and the current annual import volume reached 600,000 tons per year. about.

Ultrathin product production technology popular

On the whole, the tin plate production capacity in China is already saturated, but the key problem is that the key technology level has not kept pace and the substrate is thick. At present, the international tin plate technology is developing towards the production of ultra-thin products. The demand for tin plate below 0.28 mm in Japan accounts for about 85% to 90% of the total market volume, while the international high-quality barrel cans need to be plated. Tin plate thickness is generally 0.14mm ~ 0.19mm, China's thinnest tin plate is 0.19mm.

In addition, there are still insufficient supply of tin-plated substrates in our country, especially the supply of thin-gauge tin-plated substrates, and the quality of products produced by domestic enterprises cannot catch up with imported products. Domestic tinplate manufacturers except Baosteel, Wuhan Iron and Steel, and Zhongyue Magutie Industrial Co., Ltd., most other companies rely on the import of tin substrates, which has high production costs. However, due to the limited resources of tin-plated substrates in foreign countries, it is increasingly difficult to purchase. Coupled with the late start of tin plate production in China, lack of technical experience, product quality is unstable, including thickness tolerances, flatness, hardness, etc., and there is still a gap between the import plate, resulting in the structural contradictions of domestic production and demand is outstanding: On the one hand, overproduction of low-grade products, on the other hand, high-end products can not meet the demand in terms of output and quality, and one third of them need to be imported from abroad.

Although many research and development companies and companies in China have carried out the development and research of tin-plated substrate technology and equipment, there are few successful cases. Until 2007, China's first set of tinplate rolling production line independently developed and researched by a research unit of China—the “two-rolling and one-leveling” unit with an annual output of 150,000 tons was put into production by the production enterprises, indicating that China owned Independent research and development of tin plate production process and equipment. The production line has adopted the single-stand single-roller reversible cold rolling process and the single-stand single-pass secondary dry-smoothing process for tin plate production for the first time in China. Since it was put into operation, the unit has been operating stably and reliably, and the technical performance, process indicators and product quality have all achieved Or exceed the contract requirements, in the strip surface degreasing, the new roll surface cleaning, automatic roll line elevation adjustment, height and medium to have breakthrough innovation. At the same time, the unit also successfully applied a number of international contemporary advanced technologies, including automatic thickness control, integrated plate shape control, mixed tension control, oil and gas lubrication, automatic centering, rapid roll change, etc., to ensure the advanced nature of the equipment itself. Reliability and practicality.

Relevant experts pointed out that the successful development of domestic tinplate and tinplate production technology equipment changed the situation in which tinplates and tinplates rely on imports and production processes and rely on imported equipment to solve the development of restricted tinplate manufacturers. The supply of raw materials can meet the growing market demand for the food packaging industry. The next step is to develop tinplate production technology in China in the direction of developing and producing ultra-thin ultra-thin tinplates, laying the foundation for phasing out backward production equipment for low-end products and reducing the import of tinplates.