Reutilization method for annealing oven protective atmosphere

Abstract

The invention discloses a recycling method of protective atmosphere in an annealing furnace. The method is characterized in that the recycling method comprises the following steps: (1) the protective atmosphere is extracted from a protective atmosphere extraction outlet in the furnace; (2) the extracted protective atmosphere is cooled until the temperature is lower than 20 DEG C, and the protective atmosphere is processed through dehydration treatment; (3) after being cooled, the pressure of the protective atmosphere is risen to more than 30KPa through a blower, and then is delivered to a storage tank for storing; before being delivered into the storage tank, the content of H2 in the protective atmosphere is measured on a protective atmosphere recovering pipeline, and the calorific value thereof is calculated; if the calorific value is in the designed calorific value range, the protective atmosphere is used by a burning pipeline system directly to heat a band steel; if the calorific value is not in the designed calorific value range, natural gas starts up and is pumped in the pipeline system, the natural gas is replenished, and then the protective atmosphere is supplied to a burning system for using after the calorific value is adjusted to the designed calorific value range. The recycling method is utilized to recover the protective atmosphere in the annealing furnace, so thatthe energy is saved and the manufacturing cost is lowered; in addition, the recycling method is easy to operate, and the application range is wide.

Description

technical field The invention belongs to the production technology of oriented silicon steel, and in particular relates to a continuous nitriding annealing furnace for oriented silicon steel and a method for recycling the atmosphere in the furnace. Background technique The typical production method of grain-oriented silicon steel is as follows: use a converter (or electric furnace) to make steel, carry out secondary refining and alloying, and continuously cast into a slab. Its basic chemical composition is Si (2.5-4.5%), [C] (0.01- 0.10%), Mn (0.03-0.1%), S (0.012-0.050%), Als (0.01-0.05%), N (30-120ppm), and some component systems also contain Cu, Mo, Sb, Cr, B One or more of elements such as , Bi, etc., and the rest are iron and unavoidable impurity elements; the slab is heated to a temperature of about 1400°C in a special high-temperature heating furnace, and is kept for more than 30 minutes to make the inclusions fully Solid solution, in order to precipitate fine and di...

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Problems solved by technology

The inventor searched and analyzed the patents and documents of the traditional oriented silicon steel production method at home and abroad and the low-temperature slab heating technology based on the nitriding process to produce oriented silicon steel technology, and found that the decarburization annealing furnace in the traditional production method did not adopt protective atmosphere recovery Utilize technology, among the countries that have nitriding technology to produce oriented silicon steel, Japan has equipment patents related to nitriding furnace, but because its nitriding technology is carried out after decarburization is completed, the furnace structure is different from that of the continuous nitriding decarburization furnace of the present invention There is an essential difference. Japan's protective atmosphere recycling technology is prominently manifested in refining the protective gas and passing it into the furnace for recycling. However, due to the high requirements for the protective atmosphere and low gas recovery rate, the refining cost has increased. , the economics of atmosphere recycling are greatly affected

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