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Tin plated steel sheet and Wuxi chrome plated steel sheet (hereinafter referred to as tinplate if there is no special distinction) are typical container steels. In 2021, the global demand for tinplate will be about 16.41 million tons (metric units are used in the text). Due to thinning and competition of other materials, the consumption of tinplate in developed countries and regions (such as Japan, South Korea, the United States, Canada, the European Union, etc.) has gradually declined, but its consumption growth in developing economies has made up for and exceeded this decline. At present, the global consumption of tinplate is growing at a rate of 2% per year. In 2021, the global output of tinplate will be about 23 million tons. However, as the expansion of China’s production capacity is expected to exceed the growth of domestic demand, people worry that the gap between supply and demand will further expand. At present, Japan’s annual demand for tinplate is about 900000 tons, about half of the peak in 1991.

Under the above background, it is extremely important for Japanese tinplate manufacturers to maintain their products’ competitiveness against other container materials (such as polyethylene terephthalate and aluminum) in the domestic market. To this end, they must improve the performance of steel tanks and reduce costs through vertical integration through close cooperation with tank manufacturers. In the overseas market, it is important for them to make use of the high-tech accumulated and promoted in the domestic market to differentiate their products from those of their competitors, and improve their competitiveness through vertical cooperation with the can manufacturers.

In addition, nickel plated sheet steel can be used to make battery shell. In this field, it is also extremely important for manufacturers to accurately respond to user needs. Japanese tinplate manufacturers can certainly meet the above requirements by making full use of their technology accumulation in the tinplate field over the years.

This paper reviews the market characteristics of container materials at home and abroad in Japan, and clarifies the technical requirements that enterprises need to meet.

The use of tinplate food cans in Japan is limited

In most overseas countries, tinplate is generally used to make food cans, milk cans and serrated bottle caps. In Japan, the use of tinplate in food cans is very limited, and it is mainly used to make beverage cans. Due to the increasing use of aluminum cans, especially after Japan lifted the ban on small polyethylene terephthalate bottles (500ml or less) in 1996, tin plates in this country were mainly used to make coffee drink cans. However, for safety reasons, most coffee drink cans in Japan are still mainly made of tinplate, because many different types of coffee drinks in Japan contain milk.

As far as aluminum cans and polyethylene terephthalate bottles are concerned, their market competition in the field of coffee beverage cans has become increasingly fierce. In contrast, the biggest advantage of steel tanks is safety: acoustic inspection (the method of checking the decomposition of contents by striking the bottom of the tank and the change of internal pressure by sound) is only applicable to steel tanks, not aluminum tanks. The strength of steel tanks can maintain their internal pressure higher than the air pressure. However, if steel manufacturers continue to rely solely on this greatest advantage, steel cans will eventually be replaced. Therefore, it is necessary for steel manufacturers to develop a new type of steel cans with advantages greater than aluminum cans, which has the characteristics of attracting users and can regain the market occupied by polyethylene terephthalate bottles and aluminum cans.

Development of beverage cans and their materials

A brief review of the history of beverage cans and their materials. In 1961, the successful development of TFS (chromium plated steel sheet) with metal chromium film and hydrated chromium oxide film became the most sensational event in the field of beverage can manufacturing materials in Japan. Before that, although tinplate was the basis of Japanese canning industry and container material technology, all relevant technologies were mastered by western countries. As the most important container material, TFS was developed by Japan, and its products and manufacturing process were exported to western countries. The development of TFS took into account the depletion of global tin resources, which made TFS widely known at that time. The resin bonded cans for cold packaging developed with TFS materials reduced the sales of DI cans with aluminum alloy sheet drawn from the United States imported by Japan at that time. Steel cans subsequently dominated the Japanese beverage can market. Since then, the “Super WIMA Method” developed by Soudronic AG of Switzerland has made Japanese steel manufacturers compete to develop materials for welding cans.

The development of TFS has proved that technical innovation needs to be supported by strong market demand and technical capabilities. At present, there is no greater threat to Japanese tinplate manufacturers than the depletion of tin resources. “Safety and reliability” must be a long-term concern. As far as food and beverage containers are concerned, countries have different treatment methods for bisphenol A (BPA, an environmental endocrine disruptor), while some countries do not treat it at all. So far, Japan’s measures on “safety and reliability” are far from enough. The responsibility of the tank industry and steel industry is to provide environment-friendly, resource and energy saving containers and container materials.

It can be seen from the development history of tinplate that there is a close relationship between the development of new cans and new canned materials. As far as technology is concerned, Japanese canners have reached the world-class level, which is sufficient to support the Japanese steel industry to continuously develop new materials and processes, and promote them globally through close cooperation with other countries.

Global canning materials market characteristics

The global canning materials market has the following characteristics: first, the demand for steel cans is growing; second, food cans occupy the main market share; third, the supply of container materials is oversupply (especially in China); fourth, the world’s tinplate manufacturers compete with each other in terms of price and quality.

The rapid growth of the supply capacity of global canning materials is mainly in China. Relevant data shows that from 2017 to 2021, China’s capacity of tank making materials has expanded by about 4 million tons. However, about 90% of the medium and low grade tinplates are made of commercial grade cold-rolled steel sheets. According to the definition in JIS (Japanese Industrial Standard) and other internationally recognized standards, developed countries make tinplate into MR, D or L steel (according to JIS G 3303) by precisely controlling the steel composition, then adjust the content of non-metallic inclusions according to the end use, and strictly control the process during hot rolling, cold rolling, annealing and tempering rolling, so as to obtain the required performance of tinplate substrate. In any case, low-grade tinplate does occupy a certain market share.

What should manufacturers do in the future?

Japan’s technical level in the field of canning and container steel sheet manufacturing is recognized as world-class. However, the technology that has been proved effective in Japan cannot be easily spread to other countries, which is the market feature. When globalization became a commonly used word in Japan, although the Japanese iron making industry has carried out the globalization of industrial structure (based on the Japanese technology center, tin plating plants are built abroad), after TFS technology was shared with overseas partners 50 years ago, the expansion of cross-border technical cooperation was restrained for a long time. In order to highlight its position in the market, the Japanese steel industry must globalize the technologies it develops and promotes in China.

It can be learned from Japan’s technological development in this field that significant technological development stems from the close relationship between steel manufacturers and canners. When tinplate products are sold to overseas users, the focus of such users is only on product manufacturing, rather than stable tinplate supply. In the future, for Japanese tinplate manufacturers, it is important to highlight their product advantages by vertically integrating the guarantee capabilities of packers and canners.

——Reduce the cost of cans.

Canners must be most concerned about manufacturing costs, which is the basis for their competitiveness. However, cost competitiveness should not only depend on the price of steel, but also on productivity, canning process and cost.

Changing batch annealing to continuous annealing is a method of cost reduction. Nippon Iron has developed a continuous annealed tin plate that can replace the bell type annealed tin plate, and recommended this new material to the can manufacturers. Before shipment from the factory, the rejection rate of continuous annealed steel sheets is low, and the product quality of each steel coil is stable, so that customers can obtain higher processing efficiency, reduce production failures, and achieve a win-win situation. At present, the production orders of continuous annealing tinplate have occupied most of the orders of Japanese iron making.

Take the three piece food can body as an example. In the past, once cold rolled (SR) products with a thickness of 0.20mm~0.25mm were widely used. Nippon Iron suggests to replace it with a stronger secondary cold rolling (DR) product with a thickness of 0.20 mm or less. With this method, the unit consumption of materials is reduced due to the thickness difference, and the cost is reduced accordingly. As mentioned above, the chemical composition of tinned steel sheet is strictly controlled, and its thickness is close to the lower limit of industrial cold rolled steel, so the secondary cold rolling can effectively reduce the product thickness.

As the secondary cold rolling method is adopted, the thickness of the base metal is reduced again on the temper mill after annealing, so when the elongation is reduced, the material strength is increased. During the can making process, this often leads to flange cracking near the welded joint, or ripples during the forming of the can cover or two-piece can. Based on previous experience, the Japanese Iron Company solved the above problems by using thinner secondary cold rolling tinplate, and provided each user with the most suitable materials for various types of cans and manufacturing methods, so as to reduce the cost of canning.

The strength of a food can largely depends on its shape and material strength. In order to introduce qualified materials and applicable can design, Nippon Iron has created a “virtual can factory” – a simulation system that can evaluate the strength of food cans according to the changes of materials and can shapes.

——Focus on “safety and reliability”.

Since tin plate is used to make food and beverage containers, steel manufacturers have the responsibility to provide safe and reliable materials to users at home and abroad. The steel plate without bisphenol A is such a material. Japan Iron&Steel Co., Ltd. always pays attention to the world’s environmental protection regulations, and is determined to continue to become the world’s leading manufacturer of safe and reliable container materials by developing and providing environment-friendly container steel sheets.

Market characteristics and demand prospects of nickel plated steel sheet

Whether past, present or future, steel tank is the best container type. It is extremely important for manufacturers to cooperate closely with users, jointly pursue energy and resource economic benefits, and develop and provide environment-friendly materials. There are many container steel sheet manufacturers all over the world eager to expand their production capacity (especially in developing countries).

Nickel plated steel sheet is another kind of container material produced in Japan. The shells of primary batteries (such as alkaline dry batteries) and secondary batteries (such as lithium batteries, nickel metal hydride batteries and nickel cadmium batteries) are made of nickel plated sheet steel. The overall scale of the global market for nickel plated steel sheets is about 250000 tons/year, of which precoated plates account for about half. The precoated plate has uniform coating and is widely used in Japan and western countries to make primary batteries and high capacitance secondary batteries.

The market scale of nickel plated steel sheet is much smaller than that of tin plated steel sheet, and the number of suppliers is limited. The main suppliers in the world are Tata India (accounting for about 40% of the market share), Toyo Steel Co., Ltd. of Japan (accounting for about 30%) and Japan Iron (about 10%).

There are two types of nickel precoated sheet: nickel plated sheet and heat diffusion sheet with nickel coating diffused to steel substrate after heating. As no additional treatment is required except nickel plating and diffusion heating, it is difficult for manufacturers to differentiate their products from those of other competitors. As the external dimensions of batteries are standardized, battery manufacturers compete with each other on battery performance (depending on internal capacitance), which means that the market needs thinner steel plates. In order to increase the market share and promote the development of the battery industry, Japanese iron making must adapt to the needs of battery manufacturers and play its strong advantages in vertically integrating manufacturing processes.

The demand for nickel plated steel sheets in the battery market other than the automobile industry is rising steadily. The Japanese iron making industry is facing a good opportunity to lead the market by correctly responding to the needs of battery manufacturers. Over the past few decades, the thickness reduction technology accumulated by Japanese iron making in the field of tinplate manufacturing will effectively meet the market demand for nickel plated steel sheets for batteries. The shell of automobile battery pack is mainly made of aluminum or aluminum foil laminate and plastic film.

For steel manufacturers, it is very important to take effective measures for the research and development of steel applications.

Post time: Dec-01-2022