Development history and production status of galvanized sheet

Development history and production status of galvanized sheet

Development history

The first continuous hot dip galvanized strip production line was established in the United States in 1937, and the first continuous electric galvanized strip production line was completed in the United States in 1942. It has been in industrial production for more than 70 years.

Hot-dip galvanized products are widely used in construction, household appliances, vehicles and vessels, container manufacturing, machinery and electrical industry, almost involving the clothing, food, housing and transportation of various fields. In recent years, the world demand for galvanized steel plate is increasing, and the output growth is also very fast. In the United States, Japan and other steel production countries, the proportion of hot-dip galvanized steel plate in steel has been as high as 13%-15%.

Recently, the automobile industry pays more and more attention to the service life of materials, and the cold rolled steel plate with paint can not meet the requirements of corrosion resistance. In this case, good corrosion resistance and low cost of hot galvanized sheet began to be widely favored by automobile manufacturers.

The greatest advantage of coated steel plate is excellent corrosion resistance, paint property, decoration and good formability. In recent years, the application of coated steel plate in automobile has been increasing, and it has become the main body of automobile sheet. Countries all over the world are studying how to expand the varieties and specifications of coated plates, improve the coating process and improve the coating quality, that is, corrosion resistance, resistance to pulverization and peeling, coating property and weldability. The formability of the coated plate is always an important aspect of its application, which mainly depends on the substrate properties, coating technology and properties and forming process conditions, through the integration of advanced technology to achieve good application effect.

Production status

The development of hot-dip galvanizing production in our country is lagging behind. In the 1950s to the 1960s, 13 sheet steel flux method hot dip galvanizing units were built successively, with the capacity of 100,000 t/a, but due to low output, high cost, poor quality, environmental pollution, poor economic benefits and other defects have been stopped and transferred. From the late 1970s, our country only began to build large broadband hot-dip galvanized units.

Hot-dip galvanized strip steel is always in shortage in our country. Since the mid-1990s, about 800,000 to 1 million tons have been imported from abroad every year. With the development of domestic economy, especially the development of automobiles, household appliances and construction industry, the demand for galvanized strip steel has increased greatly. In the recent 20 years, our country has built a batch of hot dip galvanizing lines with an annual output of more than 100,000 t production lines, but from the process, equipment composition to product varieties belong to low level of traditional technology, on the variety quality and quantity can not meet the needs of our country's economic construction development, still need to build new hot dip galvanizing line to meet the market needs.

The production of zinc plate in our country has made great progress since 1990s, and the processing capacity of zinc plate is up to nearly 3 million t. The market share of domestic galvanized sheet increased rapidly, from about 27% in 1996 to 59% in 1998. The main domestic manufacturers are Baosteel, Wuhan Iron and Steel, Panzhihua Iron and Steel, Handang Iron and Steel, Bensteel and other 5 enterprises with a total production capacity of more than 1.3 million tons.

The existing hot-dip galvanizing units in our country and foreign level have the main difference in most units do not have pre-cleaning equipment, which is difficult to guarantee the quality of galvanizing surface. The existing polishing machine is a relatively simple two-roll polishing machine (four rolls for Panzhihua Steel), can not improve the mechanical properties of strip steel, especially the deep drawing property; The existing varieties are single galvanized plate, only a small amount of alloyed plate, far from meeting the needs of the market.

Our manufacturers of hot-dip galvanized steel plate produced by building materials, light industry, agriculture, transportation and other industries are the main users. Due to the limitations of the existing hot-dip galvanizing equipment, process technology and the performance of the original plate, the actual production of galvanized sheet for the automobile industry is very few.

The characteristics of galvanized steel plate: galvanized can effectively prevent steel corrosion, prolong the service life. Galvanized thin steel plate (thickness is 0.4 ~ 1.2mm), also known as galvanized iron sheet, commonly known as white sheet. Galvanized steel plate is widely used in construction, vehicles, household appliances, daily necessities and other industries.