Method for increasing temperature of semi-hardness aluminum-zinc-plating strip steel entering zinc pot

Abstract

The invention relates to the field of producing semi-hardness aluminum-zinc-plating high-strength steel by using an annealing furnace, and in particular relates to a method for increasing the temperature of semi-hardness aluminum-zinc-plating strip steel entering a zinc pot. The method is characterized in that aiming at the 0.4-0.6nm thin strip steel, the cooling capacity of a cooling system of a cold jetting section is controlled, and the temperature of protective gas at the cold jetting section can be increased, wherein the specific control steps are as follows: (1) the running speed of the strip steel in an area of a heat-preservation and slow-cooling section and the cold jetting section is 110-130m / min; (2) the power of a fan at the cold jetting section is controlled to be within 5-10% of the rated power, and the circulation amount of cooling water is reduced to be 30-50% of the total amount of the cooling water; and (3) the temperature of the protective gas at the cold jetting section is increased to be 300-320 DEG C, and the temperature of the strip steel entering the zinc pot is controlled to be 550-600 DEG C. Compared with the prior art, the method has the beneficial effects that the stability of the temperature of the strip steel entering the zinc pot is ensured, the consumption amount of the cooling water of a cooler at the cold jetting section is saved, the power output of an electric heater is eliminated, and the aim of energy saving can be realized.

Description

technical field [0001] The invention relates to the field of semi-rigid galvanized high-strength steel produced by an annealing furnace, in particular to a method for increasing the temperature of semi-rigid galvanized strip steel entering a galvanizing pot. Background technique [0002] At present, the annealing furnace for galvanizing is mainly based on the improved Sendzimir method and the United States Iron and Steel method. The process flow is as follows: [0003] Original plate preparation → pre-plating treatment (cleaning) → open flame heating → radiant tube heating → protective gas cooling (1) [0004] Or original plate preparation → cleaning → radiant tube heating → protective gas cooling (2) [0005] →Hot-dip plating→Post-plating treatment (including cooling→finishing→stretching straightening→passivation→oiling, etc.)→finished product inspection. [0006] Among them, (1) is the improved Sendzimir method, and (2) is the American Steel Union method. [0007] The i...

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Problems solved by technology

[0010] For thin strip steel with a thickness of ≤0.6mm, since the cooling fan in the spray cooling section has a minimum output requirement of 10%, after being cooled by the spray cooling fan in the spray cooling section, the temperature of the strip steel can only be maintained at about 500°C, which cannot To meet the requirements of the temperature of the strip steel entering the zinc pot, it is generally necessary to add an electric induction heater in the spray cooling section and the downflow trough to ensure the temperature of the area through the electric induction heater and heat the strip steel at the same time, but the temperature of the strip steel after the electric induction heating The temperature must be lower than the annealing temperature (610°C) to ensure that the mechanical properties of the product will not be affected by secondary heating, so that the temperature of the strip steel entering the galvanizing pot fluctuates greatly, and the surface quality and coating quality of the galvanized product cannot be guaranteed. Substrate binding force

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