Internal annealing in the middle line of hot galvanizing line
It is a hot galvanizing raw sheet which is provided directly by cold or hot rolling mill with coil. Gas protection recrystallization annealing is carried out in the hot galvanizing line
It is the annealing process and heat mirror zinc Ding Yi unite, mainly includes the inline annealing furnace, reducing furnace two, a strip in the hydrogen furnace gas flame directly heated to 450 degrees, burn of the rolling of strip surface residual oil, clean surface, after finish the strip heated to 700-700 degrees of recrystallization annealing, the cooling section control before entering zinc pot temperature at 480 degrees, finally in the case of out of touch with the air into the mirror zinc zinc pot, so, Jimmy, high yield, galvanized quality is better, this method was widely used.
The steel link"
It is a variant of Jimmy's method, it is to use only a alkaline electrolytic degreasing tank replaced the degreasing effect of oxidation furnace, the rest of the fourth order with Jimmy's method is basically the same, after the original plate into the line, electrolytic degreasing first, and then washing drying, and then through a protective gas reduction furnace for recrystallization annealing, finally argue in a sealed case into the pot hot d and zinc.This kind of method for strip steel without oxidation heating, so the surface of the oxide film is thinner, can decrease the reduction furnace protection in the hydrogen content of the gas, so, good for furnace safety and reduce the production cost, however, due to the strip into the reduction furnace without preheating, so there is no doubt increased the reduction furnace heat load, affect the service life of the furnace.Therefore, this method is not widely used.
Also known as direct flame heating method first strip steel by alkaline degreasing, and then use hydrochloric acid oxide coating on the surface of the qing court, and the water enter directly by the gas flame heating again after drying in the state of wu line retreated inside furnace, furnace through strict control of air and gas flame burning rate, in excess gas and oxygen shortage of incomplete burning flame, which result in reducing atmosphere in the furnace.To its rapid thermal recrystallization temperature and cooling strip steel under low hydrogen protection atmosphere, finally in an airtight case in liquid zinc, zinc hot town, tight tn gather together the equipment, low investment cost, high yield (up to 50 per hour), but the production process is complex, especially when the unit stop running, in order to avoid burning out strip, need to adopt the method of transverse left the stove steel belt, so many operation problem, so the hot zinc T industry adopted very little.
Sally shimron method
In 1939, American lun company put into operation a new type of hot setting unit. E was the optimal method of tu medicine. The method was to insinuate gas into the strip steel in the annealing furnace and make the strip steel reach recrystallization temperature, so it was also called gas pickling method.Using hydrogen chloride gas pickling, not only can remove oxide coating on the surface of the steel strip, and at the same time to in addition to the strip surface of oil, gas corrosion, due to the strip surface oxidation to form pits, so use Sharon method of coating adhesive particularly good, but due to the equipment corrosion is serious, this may cause high cost of equipment maintenance and update so this method is seldom used.
It is a more superior heat mirror zinc T art methods it's Jimmy, independently of oxidation furnace and reduction furnace are linked by a smaller cross-sectional area of corridor, including preheating furnace reduction furnace and cooling section, so the whole annealing furnace constitute an organic whole, the practice proved that the method has many advantages such as low security high quality and high yield advantages has been gradually known by people, its development speed is very fast, since 1965 a new line of almost all adopted the method of unit in recent years old, Jimmy, mostly is reformed according to the method.