JPS6120609B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soaking furnace for processing metal,
The present invention relates to a heating method for a heating furnace used for heat treatment, such as a heating furnace for rolling billets, or a quenching furnace, an annealing furnace, etc. for changing the properties of metal.

In order to avoid oxidation of the material to be heated, a heating furnace heats a heat medium such as combustion gas or electricity through an intermediate such as an inner cover, and uses atmospheric gas circulating within the intermediate as a heat transfer medium to heat the material. A method of brightly heating the material is generally employed. However, as a heating furnace is operated at a higher temperature, heat loss generally increases, and most of the heat loss is lost through heat flow through the furnace wall rather than through sensible heat carried away by atmospheric exhaust gas. For this reason, methods have been used to date to increase the thickness of the insulating bricks in proportion to the rise in furnace temperature. Moreover, when the material to be heated is small or when the operation is performed at a temperature below the capacity, there is a drawback that the loss of heat that flows through the wall of the heating furnace and is dissipated becomes large.

The present invention provides a heating method that prevents heat radiation and increases heating efficiency in a heating furnace with a relatively thin furnace wall without increasing the thickness of the insulating bricks. This is a heating method that prevents heat radiation in an atmospheric gas heating furnace in which a gas having a thermal conductivity smaller than that of the atmospheric gas is pressed from behind the wall of the heating furnace that raises the temperature of the material to be heated.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

1 and 2 show one embodiment of the invention. In FIG. 1, reference numeral 1 denotes a heating furnace chamber such as a heating furnace for rolling billets, a quenching furnace, an annealing furnace, etc., and is constructed with a continuous or discontinuous furnace structure. Reference numeral 2 denotes the furnace wall of the heating furnace chamber 1, which is composed of a single layer or a combination of layers of commonly used furnace wall refractory materials such as refractory bricks, ceramic fibers, castables, etc. 3 covers the furnace wall 2 of the heating furnace chamber 1 with an iron shell. That is, the heating furnace chamber 1 is heated by a heating medium (not shown) provided on the furnace wall 2 while circulating atmospheric gas.
It is configured to heat (raise the temperature of) the material to be heated 4. Further, the heating furnace chamber 1 may heat the material to be heated 4 by covering the inner cover, as in the case of generally used box annealing. Reference numeral 5 denotes a gas pipe that penetrates the furnace wall 2 by introducing an atmospheric gas having a lower thermal conductivity than a mixed gas of N ₂ and H ₂ , such as N ₂ gas, which is circulated in the furnace from behind the wall of the furnace wall 2. This prevents the flow of atmospheric gas that radiates heat. Further, the gas pipes 5 are arranged in a branched structure on the wall surface of the furnace wall 2, as shown in FIG. 1, or with shielding plates 6 buried inside the furnace wall 2, as shown in FIG. There is.

In a heating furnace as shown in FIG. 1, the present invention provides a heating furnace in which a thermally conductive gas smaller than the furnace atmosphere gas is introduced from behind the wall surface of a heating furnace chamber 1 to raise the temperature of a material to be heated 4 while circulating an atmospheric gas. For example, when the furnace atmosphere gas is a mixture of N ₂ and H ₂ , when N ₂ gas is pressurized (introduced, back pressured), the atmosphere gas flowing through the furnace wall 2 is stopped, and the atmosphere gas is removed from the heating furnace chamber 1. Heat loss is prevented.

According to the embodiments of the present invention, the thermal efficiency was higher than that of conventional heating methods.

[Brief explanation of the drawing]

1 and 2 illustrate two examples of implementing the invention. 1... Heating furnace chamber, 2... Furnace wall, 3... Iron shell, 4
... Heated material, 5 ... Gas pipe, 6 ... Shielding plate.

Claims (1)

[Claims] 1. A method for preventing heat radiation in an atmospheric gas heating furnace, which comprises pressurizing a gas having a smaller thermal conductivity than the atmospheric gas from behind the wall of the heating furnace that raises the temperature of a material to be heated while circulating the atmospheric gas.