Flue gas circulation type steel plate medium and low-temperature tempering furnace and low-temperature control method

Abstract

The invention provides a flue gas circulation type steel plate medium and low-temperature tempering furnace and a low-temperature control method. The tempering furnace integrates burner flame jet heating and circulating flue gas jet heating. The temperature of flue gas supplied to hot air jet nozzles is controllable. The hot air jet nozzles are used for replacing burners to implement flame jet. The jet frequency can be 4-5 times higher than that of the burners. Furnace gas is stirred more violently. Local overheating of steel plates is avoided, and the furnace temperature homogeneity is realized. Meanwhile, the hot air jet nozzles spray the flue gas at the fixed temperature to conduct high-frequency impulse jet impinging on the steel plates, and the convection heat exchange efficiency is improved. Through the flue gas circulation type steel plate medium and low-temperature tempering furnace and the low-temperature control method, high-precision uniform heating of the large-temperature-span heat treatment furnace can be realized, the low-temperature heat transfer efficiency is enhanced, the sides of steel plates are overheated due to the high burner flame temperature during low-temperature heating is avoided, cyclic utilization of flue gas is promoted, emission of the flue gas is reduced, and the effects of energy conservation and emission reduction are achieved.

Description

technical field [0001] The invention relates to the field of medium-thick steel plate heat treatment equipment and production technology, in particular to a continuous heat treatment furnace with a large temperature span and low-temperature heating with a temperature range of 150-800° C. and a control method thereof. Background technique [0002] High-strength heat-treated steel plates are mainly used in engineering / cement machinery, heavy mining vehicles, and military industries. Tempering treatment is required, and the treatment temperature is usually 150-800°C. Its performance is extremely sensitive to temperature, and some varieties require uniform temperature. Due to the large temperature span, conventional heat treatment furnaces and heating methods are difficult to achieve this uniformity requirement, so a special high-precision medium and low temperature tempering furnace is required. [0003] At present, the tempering heat treatment furnace is widely used to heat th...

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Problems solved by technology

The method of direct heating by the burner is adopted, the furnace temperature can be adjusted flexibly, and the response speed is fast, which can adapt to the change of large heating load and the change of high furnace temperature, but the combustion temperature at the edge burner is high at low temperature, which is easy to burn. Cause overheating of the edge of the plate, resulting in uneven temperature across the width

At the same time, for tempering furnaces with a large temperature span of 150-800°C, the burner configuration cannot achieve high pulse frequency enhanced convection in the full temperature range, and the heat transfer efficiency is slow at low temperature tempering

[0004] In order to improve the temperature uniformity of the furnace and meet the heat treatment process requirements of the plate temperature uniformity ≤±5°C during low-temperature tempering, some enterprises set up stirring fans in the heat preservation section of the heat treatment furnace to strengthen the mixing and stirring of the flue gas in the furnace, which also plays a role. To a certain effect, but the effect is not significant

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