JPH029103B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to vacuum and gas-filled electric heating equipment, and more particularly to continuous electric furnaces for the chemical heat treatment of steel parts.

The invention can be most advantageously used for vacuum carburizing in electrical technology, the automotive industry and in other fields of machine construction. Furthermore, the invention can be used for chemical heat treatment of products manufactured by powder metallurgy.

The invention is also applicable to treatments such as vacuum brazing and surface impregnation with various elements such as silicon, titanium, boron, etc.

Maximum efficiency in chemical heat treatment of parts is achieved through the use of continuous furnaces.

Hardening pusher type furnace with charging and unloading equipment arranged in one row, hardening chamber and cooling chamber (Handbook “Electrothermic” edited by APAltgauzen, Moscow
"Equipment" 1967, P.178.Refer to Fig.5-133) is a well-known technology.The furnace incorporates a pusher that feeds the parts into the surface hardening chamber and a moving device that feeds the parts into the cooling chamber. The heating chamber is fitted with a fan to circulate the medium during the carburizing process. Such a furnace was adopted by the Aichelin and Halcroft company.

The furnace works as follows. The parts are loaded into the container. The container loaded with parts is placed on the loading device and a pusher moves it into the hardening chamber. The chamber door opens and the part is passed through the door opening into the heating chamber where it is heated to carburizing temperature while moving through the chamber. The furnace generally employs a frame curtain to retain the media within the hardening chamber. The surface curing chamber is filled with saturated gas supplied thereto.
Once the carburizing process is complete, the charging door opens and the charge advances into the cooling chamber.

The furnace is a fire and explosion hazard, creates a poor working environment, and requires ventilation with special features. The furnace kit must include an environmentally controlled gas generator with high cleaning power and must also incorporate the furnace's natural gas supply. Since the carbon concentration is easily disturbed during charging and unloading operations, the carbon concentration must be precisely controlled inside the furnace. In addition, the structural members of the furnace (including the heater and lining)
It is not appropriate to increase the temperature in the furnace, since there is a large amount of soot deposits leading to damage to the heater and therefore a reduction in the furnace output.

a charging and unloading chamber equipped with a vacuum seal;
A continuous vacuum furnace for heat treatment with a hardening chamber with a thermal insulator made of fiber material and a vacuum cooling chamber with equipment for vacuum cooling and further inert gas cooling is known technology (Hays
Company's Data sheet No.771type LV, model
(See CVCQ-202436). The furnace works as follows. The seal of the surface curing chamber is closed and the container filled with product is loaded into the charging chamber. The charging chamber door is then closed, the chamber is evacuated to a predetermined vacuum, and a vacuum seal is opened to pass the container to the curing chamber, which communicates with the charging chamber and fills the chamber. The product being treated is heated to carburizing temperature and carburized while the container is moved through the case hardening chamber. Once the entire surface curing cycle has been completed, the product is advanced from there to a cooling zone, where it is transferred via another vacuum seal to an inert gas rapid cooling zone and then to a discharge chamber.

The structure of the conventional furnace is such that the product placed in the container during the heating of the charge does not absorb carbon uniformly at different temperatures, and therefore the thickness of the carburized layer varies.
It was not provided in order to obtain a uniform carburized layer. Additionally, conventional furnace designs required large amounts of carburizing gas and electrical power because the furnace had to be filled to its capacity with reactant gas. Further, a pusher type furnace having a charging chamber, a charging chamber, a heating chamber, an intermediate chamber attached by a holder to a pusher in which a heating element is mounted and moved vertically, and a cooling chamber is known in the art. (USSR Inventor's
(See Certificate No. 601317, C21D 9/00, 1978).

The furnace works as follows. The product to be processed is placed in a pan. Each loaf of bread is placed in the charging chamber, and the pusher moves the loaf of bread into the heating chamber after opening the seal, where it is held for a predetermined period of time. Then the next loaf of bread is loaded into the oven.

During each filling, the pan is gradually heated, coming under the middle chamber. When the intermediate chamber moves downward, the pan platform appears to be within the heat treatment zone.

After a certain exposure time, the pusher moves the intermediate chamber back to its initial position, the bread filled with product remains there for a certain time, and then the pusher sends the bread to the cooling room.

The bread is fed from the cooling chamber to the discharge chamber. The operation is then repeated. The intermediate chamber of the above design is not suitable for the easy sealing of the processing chamber required for chemical heat treatments carried out in a vacuum furnace. Note that the structure of the furnace is complicated due to the design of the movable chamber as described above. Continuous electric furnaces for the chemical heat treatment of components are also known ( USSR Inventor's Certificate No.456569,
(see F27B9/22 1976). The heating chamber, the chamber for vertically feeding parts into the processing chamber, and the cooling chamber are aligned, with the processing chamber located outside the row for continuous horizontal feeding of parts.

The furnace works as follows. The container containing the parts sent into the heating chamber moves along the chamber and is gradually heated. After the part is heated to a predetermined temperature, the part is conveyed from there to a vertical feed chamber and the part is moved to a processing chamber where the part is processed at the predetermined temperature. When the processing inside the processing chamber is completed, the container containing the parts is moved downward and further sent to the cooling chamber.

Conventional furnaces lack the provision for sealing the processing chamber necessary to provide effective chemical heat treatment of the components.

The present invention aims at providing a continuous electric furnace for the chemical heat treatment of steel parts, in which additional structural members, common equipment and interaction of said members are arranged on the furnace sealing element during the treatment process. minimizes the temperature effects of the heat treatment, thus sealing the processing chamber during the heat treatment, thus extending the range of industrial use of the furnace, reducing the carburizing gas and its power consumption, and improving the quality of the processed parts. will enable you to improve your

This means that a component heating chamber, a component cooling chamber and a chamber for vertical supply of components are connected to and arranged between and aligned with said heating and cooling chambers, thereby allowing continuous horizontal supply of components. in a continuous electric furnace for the chemical heat treatment of steel parts, in which, according to the invention, the part heating chamber and the cooling chamber are arranged in a vertical feeding chamber. The hearths of the two chambers are adapted for horizontal reciprocating motion, and the hearth of the processing chamber controls the processing chamber during the chemical heat treatment of the parts. A vacuum seal is provided separating it from other chambers of the furnace.

The use of the above-mentioned structural elements and common equipment and their interaction during the operation of continuous electric furnaces for the chemical heat treatment of steel parts is such that the treatment furnace is closed during the chemical heat treatment and the operating heat of the furnace is properties and thereby uniform heating of the product, resulting in improved quality of the processed product and reduced processing costs.

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The continuous electric furnace for the chemical heat treatment of steel parts consists of a case 1 (the first Figure 1).

The heating chamber 2 is made of ceramic refractory material. The hearth 7 of the heating chamber 2 is connected to a device 8 for moving the hearth 7. A device 9 for moving the parts 6 is arranged on the charging side of the heating chamber 2. The extension stop device 10 and the thermal screen 11 are connected to the heating chamber 2 facing the chamber 5 for vertical feeding of parts 6.
It is located on the terminal side.

The cooling chamber 3 is made of ceramic refractory material. The hearth 12 of the cooling chamber 3 is connected to a device 13 for moving the hearth. The extension stop 14 and the thermal screen 15 are arranged on the end side of the cooling chamber facing the chamber 5 for vertical feeding of the parts 6.

The processing chamber 4 is made from carbon-graphite material. The hearth 16 of the processing chamber 4 is connected to a device 18 used for moving the hearth and for separating the processing chamber 4 from the other chambers 2 and 3 of the furnace during the chemical heat treatment of the parts 6. Vacuum seal 1
7 is equipped.

FIG. 2, which shows a cross-section along the line - in FIG.
(FIG. 1), the structure of the hearth 7 movable in the heating chamber 2 moving on the guide 22 by means of rollers 23, and the arrangement of the heating elements 24 inside the processing chamber 4. It is shown.

A continuous electric furnace for chemical heat treatment of steel parts operates as follows.

The parts 6, which are successively introduced into the heating chamber 2 (FIG. 1), are moved by means of a device 9 over the hearths 7, 12 and 16 along the furnace. During the movement of part 6, hearths 7, 12 and 16 remain in the positions shown in FIGS. 16 is replaced by a hearth 12 (FIG. 3b). Thereafter, the hearth 7 (Fig. 3c) moves to the leftmost position, and the hearth 1
2 moves to its rightmost position and the hearth 16 rises to its uppermost position.

The stop devices 10 and 14 are extended and the hearths 7 and 12 are moved to their intermediate position (FIG. 3d);
Stop devices 10 and 14 hold part 6 in the position shown in FIG. 3c. Thermal screens 11 and 15
(FIG. 1) is closed. The hearth 16 raises the component 6 into the processing chamber 4 and seamlessly separates it from the interior space of the furnace. When the processing of the part 6 in the processing chamber 4 is completed, the hearth 16 is lowered to the position shown in Figure 3a, the device 9 moves the part 6 to the next position, and the cycle is repeated.

When an electric furnace is used for chemical heat treatment of products, for example for vacuum carburizing, the parts 6 charged into the heating chamber 2 are first heated in a vacuum or in a neutral gas medium at low pressure. Ru. Inside the treatment chamber 4, the component is carburized in a carbon-containing gas medium.
During this process, the reaction gas can be repeatedly refreshed by pumping it out and partially injecting fresh gas. The parts 6 placed in the cooling chamber 3 are subjected to diffusion and to a further heat treatment in vacuum or in a neutral gas medium. When the part 6 is unloaded from the electric furnace, the hearth 12 is placed in the position shown in FIG. 3c.

The present invention achieves the above objectives.
The use of stop devices 10 and 14 (FIG. 1) and the use of thermal screens 11 and 15 minimize the effects of temperature on the closure member of the furnace vacuum seal 17 during the heat treatment process and ensure uniform heating of the part 6. and minimize power consumption.

Since there is equipment in the furnace for sealing the processing chamber 4, the range of industrial use of the furnace can be expanded and the power consumption per ton of product produced can be reduced by 1.5 or 2 times, Reaction gas consumption can be reduced by a factor of 8 to 10.

Electric furnaces of this construction make it possible to carry out various chemical heat treatment processes and produce high-quality products. The electric furnace according to the invention prevents the release of harmful gaseous impurities and thus contributes to improved production conditions.

[Brief explanation of drawings]

1 is a sectional view of a continuous electric furnace for chemical heat treatment of steel parts according to the invention; FIG. 2 is a sectional view taken along the - line of FIG. 1; and FIG. It is a line diagram showing movement. The symbols used in the drawings are as follows. 1...Furnace case, 2...Parts heating chamber, 3...Parts cooling chamber, 4...Processing chamber, 5...Parts vertical supply pipe, 6...Parts, 7...Heating room hearth, 8... Device for moving the hearth 7, 9... Parts moving device, 10... Heating chamber extension stop device, 11... Heating chamber thermal screen, 12... Cooling chamber hearth, 13...
Device for moving the hearth 12, 14...Cooling chamber extension stop device, 15...Cooling chamber thermal screen, 16...
...Processing chamber hearth, 17...Processing chamber vacuum seal, 18
...Vacuum seal moving device, 19...Bracket,
20...Shaft, 21...Journal, 22...
...Guiding part, 23...Roller, 24...Heating element.

Claims (1)

[Claims] 1 a chamber 2 for heating the component 6, a chamber 3 for cooling the component 6, two chambers 3 for heating and cooling the component 6 connected to the chamber 5 for vertical feeding of the component 6; In a continuous electric furnace for the chemical heat treatment of steel parts, the treatment chambers 4 are arranged between 2 and aligned with them, thereby forming a row for continuous horizontal feeding of parts 6. , the two chambers 2, 3 for heating and cooling the parts 6 have extension stops 10, 14 and heating screens 11, 15 arranged on the side of the chamber 5 for vertical feeding of the parts 6; The hearths 7, 12 of said two chambers for heating and cooling are adapted for horizontal reciprocating movement, and the hearth 16 of said treatment chamber 4 is used for heating and cooling during the process of chemical wall treatment of steel parts 6. Continuous electric furnace for the chemical heat treatment of steel parts, characterized in that it is equipped with a vacuum seal 17 separating the chamber 4 from the other furnace chambers 2, 3, 5.