Low-temperature prewarming and flattening method of normalizing furnace

Abstract

The invention discloses a low-temperature preheating flattening method for a normalizing furnace, which comprises the following steps: firstly, the heating temperature of the normalizing furnace of steel is between 450 and 650 DEG C, and the total heating time is 1.2 minutes per millimeter; and secondly, when a steel plate enters the furnace, a slow-charging and quick-discharging method is adopted, wherein the charging speed is between 0.007 and 0.125 meter per second, and the discharging speed is between 0.1 and 0.5 meter per second; and impurities such as sheet iron on the surface of the steel plate are blown to be clean by blowing before straightening. The method can eliminate partial internal stress of the steel by adoption of lower heating temperature, so as to be favorable for straightening the steel plate. Moreover, because the heating temperature is lower, the temperature of the steel plate is lower after straightening and the possibility of generating re-buckling due to nonuniform cooling when the steel plate is conveyed and cooled is greatly reduced, thereby the straightening effect of the method on thin and wide plates can be better. Simultaneously, the lower heating temperature is very important to reduce the energy consumption. The method meets the technical condition requirements of a user contract, and creates great benefit when simultaneously reducing unscheduled investment of factories.

Description

technical field [0001] The invention relates to a low-temperature preheating and flattening method of a normalizing furnace, which is applied to the buckling of high-strength steel plates after being straightened in a normalizing furnace. Background technique [0002] In recent years, the amount of unplanned steel rolling mills has remained high, mainly due to the bending of the steel plate shape. Some of the high-strength steel controlled rolling cannot be straightened at high temperature in the normalizing furnace, and can only be unplanned according to the bending. Warehousing, resulting in a large number of unplanned, because its performance changed after the high-temperature straightening at 730-900°C in the normalizing furnace, and the yield strength dropped significantly, which could not even meet the technical requirements of the user contract, and straightened after normalizing The surface quality of the steel plate is deteriorated by advanced technology, and the su...

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Problems solved by technology

[0002] In recent years, the amount of unplanned steel rolling mills has remained high, mainly due to the bending of the steel plate shape. Some of the high-strength steel controlled rolling cannot be straightened at high temperature in the normalizing furnace, and can only be unplanned according to the bending. Warehousing, resulting in a large number of unplanned, because its performance changed after the high-temperature straightening at 730-900°C in the normalizing furnace, and the yield strength dropped significantly, which could not even meet the technical requirements of the user contract, and straightened after normalizing The surface quality of the steel plate is deteriorated by advanced technology, and the surface of the steel plate is prone to defects such as iron sheet pressing, normalized roll marks, and normalized pits, resulting in unplanned steel reformation, wasting energy consumption, complicating the production process, and increasing the cost of the intermediate process of the steel plate The transfer of transportation prolongs the production cycle of the steel plate, causing huge property losses to the company, and also damages the company's image and reputation

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