Roller hearth type plate continuous furnace and tempering method thereof

Abstract

The invention discloses a roller hearth type plate continuous furnace and a tempering method thereof. An external circulation concurrent heating system is arranged on the rear part of a furnace body.The external circulation concurrent heating system comprises a hot blast stove, an after-burning device, a circulating fan, a main valve, a hot air pipeline and jetting heating devices. The hot blaststove is provided a furnace gas inlet, an after-burning device installation port, a furnace gas outlet, a temperature measurement installation port and a cold air inlet, the furnace gas inlet is connected with a furnace gas outlet of the furnace body through the main valve, the after-burning device installation port is used for installing the after-burning device, the furnace gas outlet is connected with an inlet of the circulating fan, and the temperature measurement installation port is used for installing a temperature sensor. An outlet of the circulating fan is connected with the jetting heating devices through the hot air pipeline, and one branch valve is arranged corresponding to each jetting heating device. The jetting heating devices extend into the furnace body and are distributedon the upper surface and the lower surface of a steel plate needing processing, and are provided with a plurality of nozzles on the sides facing the surfaces of the steel plate, and the lower jettingheating devices are located between hearth rollers. According to the roller hearth type plate continuous furnace, during high-temperature tempering, the adverse impact caused by an open fire heatingdevice to the uniformity of the furnace temperature and the heating uniformity of steel plates is reduced.

Description

technical field [0001] The invention belongs to the field of plate heat treatment, and in particular relates to a roller hearth type plate continuous furnace and a tempering method thereof. Background technique [0002] High-strength wear-resistant steel plates (such as NM360, NM400, NM500, etc.) are widely used in vehicles, ships, mining equipment, construction machinery and cement equipment. The production process is generally hot rolling + quenching + low temperature tempering process, tempering The process temperature is generally 200-400°C. In order to reduce the brittleness and quenching stress of the steel while maintaining high hardness, the tempering temperature is even as low as 150°C for special specifications and varieties. [0003] For large-scale wide-thick plate and medium-thick plate production plants, the tempering treatment of steel plates is generally realized by an open flame heating roller hearth plate continuous furnace. Fire and high temperature tempe...

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Problems solved by technology

[0003] For large-scale wide-thick plate and medium-thick plate production plants, the tempering treatment of steel plates is generally realized by an open flame heating roller hearth plate continuous furnace. Fire and high temperature tempering treatment, but in the actual production process, especially during low temperature tempering, due to the low furnace temperature, the flame and high temperature flue gas generated when the burner is working can easily cause local high temperature, resulting in furnace temperature uniformity index Poor (≥±10°C, or even higher), unable to ensure the uniformity of steel plate heating temperature and uniformity of structure properties, it is easy to fail to pass the relevant quality system certification (such as CQI-9), which is not conducive to the production of high-end heat treatment products and sales

[0004] Although on the basis of the existing equipment, engineers and technicians have improved the uniformity of the furnace temperature by increasing the disturbance impeller and using the fire pulse of the burner size, etc., it still cannot fundamentally solve the problem caused by the local high temperature when the burner is working. Due to the impact of low temperature tempering, the furnace temperature uniformity index cannot be reduced to within ±5°C

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