JP2508556B2 - Combined annealing and quenching furnace - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace which performs both annealing and quenching in a non-oxidizing atmosphere.

[0002]

2. Description of the Related Art Typical equipment of a conventional furnace for quenching and annealing in a non-oxidizing atmosphere is shown in FIG. 4A is a front view and FIG. 4B is a side view. The furnace equipment includes a front chamber 10, a heating furnace 20 in which a nitrogen gas or the like is blown into a non-oxidizing atmosphere, a cooling chamber 30 for annealing and a quenching oil tank 40 for quenching
It basically consists of rooms. For quenching, the work heated to about 600 ° C. in the heating furnace 20 is extracted into the front chamber 10, immediately placed in the quenching oil tank 40, cooled and quenched. That is, three chambers except the cooling chamber 30 are used. On the other hand, in the annealing treatment, the work heated to about 600 ° C. in the heating furnace 20 is extracted into the front chamber 10 and cooled in the cooling chamber 30 for a long time until the temperature reaches 200 ° C. or lower. Since the cooling chamber 30 has a high temperature for a long time during the annealing process, the wall surface is exposed to the high temperature and deforms. Conventionally, the wall surface of the cooling chamber 30 is cooled with water to prevent its deformation.

In Japanese Patent Laid-Open No. 63-28853, there is used a cooling chamber which also functions as a vacuum barge chamber, a heating chamber adjacent to the cooling chamber, and a furnace facility in which a quenching oil tank is formed immediately below the cooling chamber. A batch carburization method is described.

[0004]

The conventional annealing / quenching furnace requires a cooling chamber 30 for annealing in addition to the quenching equipment consisting of the front chamber 10, the heating furnace 20, and the quenching oil tank 40. Since the equipment has four rooms, the equipment is large and the installation area is large. Further, since water is used for cooling the wall surface of the cooling chamber 30 installed above the quenching oil tank 40, if water leaks and water enters the quenching oil tank 40, there is a risk of causing a serious accident. That is, when water is mixed in the quenching oil tank 40, when a work heated to about 600 ° C. is added for quenching, the water rapidly becomes steam and the volume expands about 1200 times, so-called steam explosion occurs. cause. The present invention aims to provide a quenching and quenching furnace with high safety while performing annealing by using both the front chamber 10 and the cooling chamber 30 and making the quenching and quenching furnace into a three-chamber structure to downsize the equipment. It is intended.

[0005]

According to the present invention, a heating furnace is provided on the side of a front chamber / cooling chamber in which a front chamber and a cooling chamber are integrated,
A quenching bath is installed below the antechamber / cooling chamber, and quenching oil in the quenching bath is circulated as a cooling liquid for the outer wall of the antechamber / cooling chamber, and non-oxidized to the antechamber / cooling chamber during annealing. This is a furnace for both annealing and quenching configured to introduce an atmosphere gas.

[0006]

In the heating furnace, the work is heated in an unoxidized state, held for a predetermined time, soaked and transferred to the antechamber / cooling chamber, and an anoxidizing gas is supplied to the antechamber / cooling chamber. Cooled quenching oil circulates on the outer wall of the antechamber / cooling chamber, which prevents deformation of the external wall and even if the antechamber / cooling chamber is near a high-temperature heating furnace, The chrome is annealed by being gradually cooled with a non-oxidizing atmosphere gas.

[0007]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross section of the front of the annealing and quenching furnace,
FIG. 2 is a sectional view taken along line XX of FIG. In the figure, 1
Is a front chamber / cooling chamber in which a conventional front chamber and a cooling chamber are integrated, and the heating furnace 2 is arranged on the side of the chamber via an inner furnace door 3.
A quenching oil tank 4 is installed below the antechamber / cooling chamber 1 and is annealed to form a quenching / combining furnace with these three chambers. A cooling liquid passage 1a is formed with a double structure of the ceiling and the side wall of the antechamber / cooling chamber 1, and the quenching oil tank 4 to the pump 5 are formed in this passage.
The outer wall is cooled by passing the quenching oil cooled through the heat exchanger 6, and the quenching oil that has cooled the front chamber / cooling chamber 1 is returned to the quenching oil tank 4. A non-oxidizing atmosphere gas such as nitrogen gas is constantly supplied from the gas supply device 7 to the heating furnace 2 via the valve 8 and the flow meter 11, and the front chamber / cooling chamber 1 is also connected via the solenoid valve 9 and the flow meter 11. So that it is supplied at a predetermined time.

Next, a description will be given of the annealing treatment method using the annealing and quenching furnace. FIG. 3 shows a method of feeding a non-oxidizing atmosphere gas such as nitrogen gas during annealing. The upper part of the figure shows the work furnace and the work room
The temperature of the gas is shown, and the middle and lower parts of the figure show the state of supply of nitrogen gas to the heating furnace and the front chamber / cooling chamber, respectively.
In the heating furnace 2 in which nitrogen gas is constantly supplied from the gas supply device 7 at a constant flow rate, the work is heated to about 600 ° C. in a non-oxidizing state, held for a predetermined time and soaked, and the furnace door 3 is opened. To the front chamber / cooling chamber 1, the furnace door 3 is closed, and the solenoid valve 9 is opened in the front chamber / cooling chamber 1 to supply nitrogen gas. Since quenching oil cooled through the pump 5 and the heat exchanger 6 circulates in the ceiling 1 and the side wall passage 1a of the antechamber / cooling chamber 1, the antecedent / cooling chamber 1 has a high temperature inside door. Even if it is near 3, the work is gradually cooled by the atmospheric gas and annealed well. When the annealing process is completed, the electromagnetic valve 9 is closed, and the supply of the atmospheric gas to the antechamber / cooling chamber 1 is stopped.

In the quenching treatment, the work heated in the heating furnace 2 is extracted into the front chamber / cooling chamber 1 and then put into the quenching oil tank 4 as in the conventional case. The temperature of the quenching oil in the quenching oil tank 4 can be set in the range of 40 to 180 ° C according to the type of work. For example, when the oil temperature is 40 ° C, the oil temperature rises to about 70 ° C when a heated work is added,
The temperature of the quenching oil can be controlled by circulating the quenching oil through a known heat exchanger (not shown). For example, Japanese Utility Model Application Laid-Open No. 57-59859 discloses a quenching device for introducing cooled quenching oil from a lower part of a quenching oil tank while diffusing it.

In the antechamber / cooling chamber 1, there is no risk of the outer wall being cooled by the quenching oil cooled by the heat exchanger 6 and being deformed.
Even if the quenching oil for cooling leaks, if it leaks to the outside, it can be easily found by daily inspection, and if it leaks in the antechamber / cooling chamber 1 that is difficult to check, the leaked oil Returning to the quenching oil tank 4 below, there is no danger of causing a steam explosion as in the case of using water as the cooling liquid.

[0011]

According to the present invention, by integrating the front chamber and the cooling chamber, the annealing and the quenching / combining furnace can be configured to have three chambers, and the equipment can be downsized. Further, since the quenching oil in the quenching tank is used as the cooling liquid for the outer wall of the antechamber / cooling chamber, there is no danger of steam explosion as in the case of using water as the cooling liquid, and safety is guaranteed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a diagram showing a method of feeding a non-oxidizing atmosphere gas during annealing of the present invention.

FIG. 4 is an explanatory view of a conventional quenching and annealing combined furnace.

[Explanation of symbols]

 1 Front chamber / cooling chamber 2 Heating furnace 3 Inner door 4 Quenching oil tank 5 Pump 6 Heat exchanger 7 Gas supply device

Claims (1)

(57) [Claims] 1. A heating furnace is provided on the side of a front chamber / cooling chamber in which a front chamber and a cooling chamber are integrated, and a quenching tank is installed below the front chamber / cooling chamber. A quenching oil is circulated as a cooling liquid for the outer wall of the antechamber / cooling chamber, and a non-oxidizing atmosphere gas is introduced into the antechamber / cooling chamber during annealing. Furnace.