Development of galvanized sheet

Development of galvanized sheet

The increase of domestic consumption of galvanized sheet is mainly driven by imports. In recent years, the import of galvanized sheet has increased year by year. The main imported varieties are galvanized sheet, but the proportion of galvanized sheet imports has decreased year by year; Accordingly, the import proportion of hot-dip galvanized sheet has increased year by year. In 2003, the import volume of hot-dip galvanized sheet exceeded that of electrogalvanized sheet for the first time in China.

Domestic development

Development of High Performance Hot dip Galvanized Sheet at Home and Abroad

1. Overview

At present, there is still a certain gap between China's iron and steel industry and the world's advanced level in terms of variety, quality, cost, service and labor productivity. Facing the increasingly fierce international and domestic market competition, we must accelerate the pace of structural adjustment. This is not only the need for the survival and development of China's metallurgical industry, but also the development trend of the world's metallurgical industry today. Hot Dip Galavnizing was invented in the middle of the 18th century. It was developed from the Hot Dip galvanizing process. After 50 years of development, the continuous hot-dip galvanizing process for steel strip has become a mature and advanced industrial technology. Up to now, hot-dip galvanizing is still the most common and effective process measure used in steel corrosion prevention methods. In the construction industry, it is used for light steel keel, building floor panel, corrugated board, rolling shutter door, etc. of various industrial and civil buildings; In the field of household appliances and light industry, it is used for the shells and soleplates of various household appliances; Galvanized steel sheet is widely used in light industry, household appliances, automobile and construction industry. In the automotive industry, it is used for car body, shell, inner plate, bottom plate, etc. China has made great efforts to develop power, transportation, communication, energy and urban infrastructure. With the strong development of construction, household appliances and automobile industries, China's galvanizing industry is facing unprecedented opportunities and huge markets.

In the past 20 years, the continuous hot dip galvanizing technology, equipment and corresponding control means for steel strip have been greatly developed, which enables galvanized sheet to meet the stringent requirements of automobile panels and household appliances, and thus has the potential to be replaced with its low cost and excellent corrosion resistance compared with the galvanized alloy steel strip. This project plans to learn from foreign advanced high-performance automotive hot-dip galvanizing production technology and equipment development technology and experience, through technological innovation, optimization design, precision manufacturing and foreign technical cooperation, to break through the bottleneck that restricts the development of China's high-performance automotive hot-dip galvanized steel production technology and equipment. At the same time, the significance and prospect of the development of hot-dip galvanizing technology in the sustainable development of national economy, energy conservation and mineral resources are discussed.

2. Development Situation of High grade Hot dip Galvanized Sheet for Automobile at Home and Abroad

The products of the automobile industry have the requirements of high efficiency, high reliability and high integration. The hot-dip galvanized steel sheet for automobiles is the best product among the galvanized steel sheets. Since 1975, when the United States first applied hot-dip galvanized sheet to the automobile industry for more than 20 years, all major automobile producing countries in the world have been working hard to develop and develop high-quality hot-dip galvanized sheet with the goal of corrosion prevention and comprehensive consideration of weldability, coating ability and formability, and have made a series of technical progress, including the chemical composition of steel substrate, the rolling quality of steel plate surface, and the uniformity of hot-dip galvanized coating thickness, A series of technical problems such as the optimum structure and process control of alloying. After 20 years of research, the above technical problems and the process equipment to complete this technical requirement have been basically solved and have begun to be widely used in automobiles. The successful application of these technologies can greatly improve the working condition of automobiles, prolong their life and save energy.

High surface quality, high strength and high deep drawing are the basic conditions necessary for automobile panels. The coating surface quality is directly related to the roughness and cleanliness of the sheet surface quality, the chemical composition of the strip steel and its stamping formability. At the same time, the hot plating process, the composition of the zinc solution, and the hot plating equipment are also important factors that affect the coating surface quality. The high strength and high stamping property are closely related to the chemical composition, physical properties, heat treatment process and hot plating performance of the hot-dip galvanized substrate. The following will focus on the development status and trend of the coating varieties, substrates, processes and equipment of high shield hot-dip galvanized sheet for automobiles at home and abroad.