Introduction to the packaging steel strip continuous annealing

Packing steel strip continuous annealing profile steel strip continuous annealing furnace in hot galvanizing production line, in fact similar to general straight through continuous annealing furnace. In improvement, Jimmy's method, it consists of preheating furnace, reducing furnace, cooling section of the three basic parts. At the end of the annealing furnace consists of a rigid beam is fixed, so that in the furnace when heated, can rely on installed in the bottom of the furnace body sliding pulley in a fixed orbit, which can make the furnace body free expansion in the direction of steel into the mouth. Usually, the annealing furnace of the thermal expansion rate is about 0. 05%. The length of the annealing furnace, based on comprehensive productivity and other parameters of the unit, so that each line is not the same. Hot dip galvanized the original plate after annealing furnace to achieve two purposes. First, the steel strip in annealing furnace heated to a certain temperature. First preheat the strip in the preheating furnace to the recrystallization temperature, then the strip in the reducing furnace heated to above the recrystallization temperature and heat preservation, soaking, the steel strip in the cooling section is cooled to the zinc pot temperature, the heating curve as shown in figure 61. Second, we should make the strip has a clean oxide free of active surface, and make zinc strip seal into the pot for galvanizing. Production, in the annealing furnace with protective gas containing hydrogen, and always be positive pressure operation. Iron oxide on the surface of the steel strip by hydrogen reduction in the reduction furnace, at the same time generate steam. If the water vapor is gathered in the oven. Too much, not only cannot have reduction effect, it will cause the strip oxidation. Therefore, it must immediately ruled out water vapor, the protection of the furnace gas constantly updated. Fresh gas is mainly composed of the protection of access to the end of the annealing furnace, then reverse if steel belt running direction, if the annealing furnace inlet flow, thus achieve the goal of the update of shielding gas. According to the experience, the preheating furnace and reduction furnace hearth pressure keep in 3 - respectively 5 and 7 8 mm water column is more appropriate. Force is too high, if furnace, adverse to the sealing of the furnace, it would be because of air leakage in the yan, protective gas caused by too much waste. However, furnace pressure control is too low, also have the risk of negative pressure. Production practice proves that the furnace pressure mainly depends on the amount of gas combustion exhaust gas preheating furnace. But by controlling the exhaust gas outflow properly control the furnace pressure. And tried to control by adjust the volume of protective gas flux into the furnace pressure approach doesn't work. At present, the furnace pressure control has the following three, one is to use bigger preheating furnace inlet, and then made of sweet hot material such as glass or asbestos cloth curtain hanging in front. In this way, through the drape of increase or decrease quantity can regulate the amount of exhaust gas in furnace, so as to achieve the aim of furnace pressure control. Second, the beam with a narrow entrance Han heat furnace, and in the preheating furnace to open the entrance area has one or two skylights, so through the skylight lift and fall, can control the furnace pressure, three is the preheating furnace generated by flue waste gas to the factory, so the smoke into the cross-sectional installed an electric butterfly valves, butterfly valves control through the corner, can effectively control the amount of exhaust gas preheating furnace, which can achieve the purpose of accurate control of the furnace pressure, this is a more advanced method.