Control method for ultralow oxygen content in roller hearth type thermal treatment furnace

Abstract

The invention provides a control method for ultralow oxygen content in a roller hearth type thermal treatment furnace. The control method for the ultralow oxygen content comprises the following steps:(1) setting the steel charging speed to be 35 m / min to 45 m / min; (2) opening an electromagnetic valve which is correspondingly arranged in a corresponding region to charge nitrogen when the positivedeviation of a dynamic value and a set value is larger than or equal to 10 ppm; and closing the electromagnetic valve when the dynamic value satisfies a limitation condition; (3) thermally treating asteel plate inside the thermal treatment furnace, setting the seventh to sixteenth regions inside a hearth as high-temperature regions, and quickly heating the steel plate inside the high-temperatureregions; and (4) after the steel plate is heated to a target temperature inside the thermal treatment furnace, opening a discharging furnace door, and discharging the steel plate from the furnace at adischarging speed of 15 m / min to 60 m / min. The control method provided by the invention has the effects of effectively preventing the problem about nodulation of a furnace bottom roller due to over-high oxygen content in the furnace, simultaneously effectively reducing the usage amount of nitrogen and lowering the nitrogen and coal gas consumption cost.

Description

technical field [0001] The invention relates to the field of steel plate heat treatment, in particular to a method for controlling ultra-low oxygen content in a roller hearth heat treatment furnace. Background technique [0002] The roller hearth heat treatment furnace is heated by radiant tubes, and has the characteristics of high heating uniformity and precise temperature. The nitrogen protection in the furnace is one of the indispensable and important processes to improve the performance of the plate and produce high-grade, high-surface quality wide and thick plate products. First, it is also the ultimate guarantee for wide and thick plates to obtain good performance. However, due to reasons such as unscientific nitrogen control methods in the furnace, the amount of nitrogen used is large, the gas consumption increases, and the production cost remains high. Moreover, the oxygen content in the heat treatment furnace is too high, which makes the problem of nodules on the h...

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Problems solved by technology

[0004] The object of the present invention is to provide a method for controlling the ultra-low oxygen content in a roller hearth heat treatment furnace. Aiming at the above-mentioned deficiencies in the prior art, by interlocking the furnace door and the thickness of the steel plate, the opening height of the furnace door is dynamically controlled, and the heat treatment is scientifically set. The temperature of each area in the furnace realizes the ultra-low control of the oxygen content in the heat treatment furnace of 2-100ppm, which effectively prevents the problem of furnace bottom roll nodules caused by excessive oxygen content in the furnace; at the same time, it effectively reduces the amount of nitrogen used and reduces nitrogen and gas consumption cost

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