The development of hot galvanizing technology is closely related to the development of annealing technology of steel. According to different annealing methods of hot-dip galvanizing production line and its development history [IH], we can generally divide hot-dip galvanizing production methods into the following five categories.Method
(1) Silas (Selas) production line, Silas method of continuous hot galvanizing production technology and equipment, as well as a way to, for annealing line, and can be used after the bell type annealing furnace manufacture machine of continuous hot galvanizing, set and process. It was manufactured and put into production in 1947 by Syracuse of the United States. Due to its characteristic is using direct gas flame heating plate to annealing (use only when annealed plate roll preheat plates), so they are called direct flame heating method, but due to the production process is complicated, especially in furnace temperature, high, easy to appear when parking burn out the phenomenon of strip steel, so the application is not common.
(2) Sharon method (Sharon) : Sharon galvanizing is built in 1939 by Sharon steel companies in the United States a hot, "galvanized steel production line of the methods used by, its characteristic is within annealing furnace has been heated plate spray, HCI gas, so it is also known as pickling process gases. However, due to the use of HCI gas at a high temperature, it is easy to cause corrosion of the equipment, which requires frequent maintenance and replacement of the equipment. The cost is high. Therefore, this method is rarely used and popularized.
(3), Jimmy's method (Sendzimir) : 1931 poles, Jimmy, the annealing process and hot dip galvanized process, the tent together as a whole, Jimmy, who invented the world-famous for method, really opened up a continuous hot strip steel, plated zinc production in the new era, sen Jimmy's method is an example of inline annealing most representative, the inside line, annealing furnace mainly includes two parts of the oxidation furnace, reducing furnace. Production process is divided into four sections: strip in oxidation furnace heated to a temperature of about 450 ℃, directly by the gas flame on the surface of the steel strip on the reduction furnace with protective gas oxidation iron reduction cavernous pure iron, through reducing furnace steel strip and heated to 700 ℃ to 800 ℃ is complete,Crystal annealing, after cooling, without contact with air directly into the zinc pot for hot galvanizing.This method has been widely used because of its high yield and good quality.
(4) United States steel corporation (uss): in 1948, the United States steel corporation designed and put into production a hot-key zinc strip steel production line. The method adopted is called United States steel corporation. It is characterized by electrochemical method for degreasing treatment, the annealing stage only consists of reduction furnace and cooling part, the heating part all USES radiation heating.
(5) improved senkimil method (M.S): Of armco companies in the United States in 1965 in Silas method, on the basis of the first, once developed, Jimmy's method, modified sen called Jimmy method, its main characteristic is the sen, Jimmy, independently of oxidation furnace and reduction furnace, linked by a smaller cross-sectional area of corridor, such, including preheating furnace, reducing furnace and cooling section of the annealing furnace and constitute a organic whole. In the 1960 s and 80 s, improved, Jimmy's method in hot galvanizing production accounts for absolute advantage In the late 80 s to 90 s, with the wide application of galvanized sheet in the automotive industry, the galvanized sheet is higher and higher quality requirements, using electrolytic cleaning section and the total radiation tube heating furnace of steel union method because of its good qualityScenery is favored.