JPS5948927B2 - heat treatment furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat treatment furnace equipped with a direct-fired burner and a radiant tube, or a direct-fired burner and an electric resistance heater as a heat source.

As is well known, conventional heat treatment furnaces include those equipped with direct-fired burners that blow combustion flame directly into the furnace, thereby directly heating the object to be heated; Some types include a heat dissipation tube called a radiant tube, or an electric resistance heater to indirectly heat the object.

These heat treatment furnaces are suitable or unsuitable depending on the type of material to be heated.For example, even if the material to be heated is the same copper or copper alloy, the direct heating method is not suitable for heat treating pure copper, nickel silver, or cupronickel. However, indirect heating is not suitable for heat treatment of brass, and direct heating is suitable.

In other words, the direct heating method heats the furnace by filling the furnace with reducing atmospheric gas generated by a direct-fired burner, but pure copper, nickel silver, and cupronickel cannot be completely bright annealed and oxidation occurs. Therefore, it is necessary to pickle after annealing, which has the drawback of increasing equipment costs and running costs.

If this point-to-point liquid heating method is adopted and atmospheric gas is supplied from a gas generator installed separately in the furnace, there is almost no risk of oxidation of pure copper, nickel silver, or cupronickel, and therefore pickling is not necessary. It was suitable because there was no such thing.

However, in the case of brass, when it is heated above approximately 425°C, the zinc content in it evaporates and this may adhere to metal objects such as conveyor rollers in the furnace and cause scratches on the heated object, so indirect heating method is not recommended. If this occurs, it is necessary to increase the amount of atmospheric gas supplied to the furnace to dilute the zinc vapor concentration within the furnace to a certain level, and to do this, 10 times more atmospheric gas than the normal amount must be consumed. Although this would necessarily be extremely uneconomical,
If the direct heating method is adopted, the atmosphere in the furnace can be replaced quickly, and the zinc vapor can be easily discharged out of the furnace along with the exhaust gas.Therefore, the direct heating method is suitable for heat treating this brass.

For this reason, in the past, even if the same copper or copper alloy metal was to be heat treated, it was necessary to install a direct heating type heat treatment furnace and an indirect heating type heat treatment furnace, respectively, which resulted in a large burden on equipment costs. there were.

The present invention has been made in view of the above, and is a single heat treatment furnace equipped with a direct-fired burner and a radiant tube or electric resistance heater, so that direct heating or indirect heating can be performed depending on the type of object to be heated. It is something.

To explain the heat treatment furnace of the present invention in more detail according to the embodiment diagrams, 1 is an object to be heated, 2 is a furnace body, 3 is an in-furnace roll that supports the object to be heated 1, and 4 is a rotatable support for the in-furnace roll. The bearing 5 is a sprocket that rotates the furnace roll in a predetermined direction, and the object to be heated 1 enters from the inlet 6 through the rotation of the furnace roll 3 and is continuously transported inside the furnace in the direction of the arrow shown in the figure. be done.

Direct-fired burners 7a and 7b are respectively provided on the side wall of the furnace body 1 at regular intervals along the transfer direction of the object to be heated 1, and 8
Radiant tubes a and 8b are placed between the direct-fired burners.

As is well known, the radiant tubes 8a and 8b are cylindrical tubes that burn fuel and radiate the heat to the surroundings.
Recuperators a and 9b recover heat from the exhaust gas, and exhaust hoods 10a and 10b.

Further, 11 is a flue formed in the ceiling near the entrance 6 of the furnace body 2, 12 is a recuperator provided in the flue, 1
3 is a damper that adjusts the exhaust volume through the flue 11, and 14 is a gas supply pipe for supplying atmospheric gas from a gas generator (not shown) into the furnace body 2.

Reference numeral 15 indicates a cooling chamber for subsequently cooling the object to be heated 1 that has passed through the furnace body 2, and reference numeral 16 indicates a gas supply pipe for supplying atmospheric gas to the cooling chamber.

In a heat treatment furnace configured in this way, for example, when the object to be heated 1 is brass, when the direct-fired burners 7a and 7b are combusted, a large amount of atmospheric gas is generated in the furnace. is easily discharged from the flue 11 to the outside of the furnace, so the concentration of zinc vapor in the furnace is kept below a certain level, and zinc vapor does not adhere to the hardware in the furnace to the extent that it causes damage to the object to be heated 1. .

In this case, the gas supply pipe 14 is closed, and the radiant tubes 8a, 8b may be used auxiliary to supplement heating.

On the other hand, when heat treating pure copper, nickel silver, or cupronickel, the direct firing burners 7a and 7b are stopped and the radiant tube 8 is used exclusively.
A and 8b are used as heat sources, and atmospheric gas is supplied into the furnace from the gas supply pipe 14 to completely prevent oxidation and perform bright heat treatment.

As explained above with respect to the embodiments, the heat treatment furnace of the present invention is
Since it is possible to adopt the appropriate heating method depending on the type of material to be heated, a wide range of metals can be heat treated with a single heat treatment furnace, whereas previously separate equipment was required for each type of heating method. As a result, equipment costs are significantly reduced,
This has extremely beneficial effects industrially.

In the above embodiments, a radiant tube was used as the indirect heating source, but it goes without saying that an electric resistance heater may also be used as the heating source.

[Brief explanation of drawings]

The drawings show an embodiment of the heat treatment furnace according to the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line X--X in FIG. -Y line sectional view. 1... Heat target, 2... Furnace body, 7a,
7b...Direct fire burner, 8a, 8b...
...Radiant tube.

Claims (1)

[Claims] 1. A heat treatment furnace that continuously transfers a material to be heated into the furnace, in which a plurality of direct-fired burners are provided at regular intervals along the direction of transfer of the material to be heated, and furthermore, a A heat treatment furnace characterized in that a radiant tube or an electric resistance heater is arranged in each of the parts.