DE3233361A1 - Continuous electric furnace for the chemical/thermal treatment of steel components - Google Patents

Abstract

This electric furnace comprises a heating chamber (2) for steel components (6), a chamber (5) for vertical feed of the steel components (6), and a cooling chamber (3), which are arranged in one line. The chamber (5) for the vertical feed of the steel components (6) is connected to a technological chamber (4) having a bottom (16) which is provided with a vacuum seal (17) which separates the technological chamber (4) from the other chambers (2, 3, 5) of the furnace during the process of the chemical/thermal treatment of the steel components. The chambers (2, 3) for heating and cooling the steel components have, on the side of the chamber (5) for the vertical feed of the steel components (6), stops (10, 14) which can be moved out, and heat shields (11, 15), whereas their bottoms (7, 12) are designed for horizontal to-and-fro movement. <IMAGE>

Description

Continuous electric furnace for chemical-thermal

Treatment of Steel Parts The present invention relates on vacuum and gas-filled electrothermal systems and concerns in particular continuous electric furnaces for the chemical thermal treatment of steel parts the features of the preamble of the claim.

The arrangement according to the invention can be used in electrotechnical, motor vehicle, Tractor construction industry and in other branches of mechanical engineering in the Vacuum case hardening can be used.

It can also be used in the chemical-thermal treatment of powder metallurgy products.

The furnace according to the invention can also be used in such processes as soldering under vacuum and saturation of the surface with various elements, e.g. silicon, Titanium, boron and others are used.

Continuous ovens are used to ensure high productivity to be achieved in the chemch-thermal treatment.

A pusher-type furnace for case hardening is known (reference book Elektrotermicheskoe oborudovanie ", electrothermal equipment, under reaction of A.P. Altgauzen, Moscow, 1967, p. 178, fig. 5-133), the loading and unloading devices, a case hardening chamber and a cooling chamber which are arranged in line are. Workpieces are fed into the case hardening chamber by means of a Pusher, while the workpieces are fed into the cooling chamber through a Shifting device is effected. The heating chamber is equipped with a fan to generate a circulation during case hardening.

The furnace is operated as follows. The loading of workpieces takes place by means of a container. For this purpose, a container with workpieces is placed on the loading device and pushed into the case hardening chamber by the pusher. In addition the work door is lifted and the workpieces pass through the opening that has been formed into the heating chamber. They are set to the operating temperature as they pass through the chamber heated up. To the atmosphere of the To keep the case hardening chamber, a fiber curtain is usually used. In the case hardening chamber a saturation gas introduced. When the case hardening is complete, the discharge door will open opened and the batch with the workpieces is fed into the cooling chamber.

The furnace is at risk of fire and explosion and contaminates the surrounding air in the hall and requires special ventilation. Special generators are required to operate the furnace be used for the atmosphere to be monitored with a high degree of purification. In addition, the furnace must be equipped with natural gas supply lines. It is necessary, precisely maintaining the carbon potential in the furnace, but this during charging of the furnace with workpieces and the discharge of the same can easily be disturbed. In addition, the components of the furnace (heater, feed) do not allow increase the temperature in the furnace as a result of soot formation and the failure of the heater, thereby affecting furnace performance.

l is also known a continuously operating vacuum furnace for Heat treatment with cooling in a vacuum and subsequent cooling in a stream of inert gas (Catalog "Data Sheet", No. 771, Type IV, Mod. CVCQ -202436), which has a loading and a discharge chamber with vacuum seals, a case hardening chamber with thermal insulation, which is made of a pulp, and comprises a vacuum cooling chamber.

The operation of this furnace is as follows. A container with work pieces is placed in the loading chamber closed lock to the case hardening chamber brought in. Then the door of the loading chamber is covered and the chamber to Generating the required negative pressure, after which the charging chamber is evacuated with the case hardening chamber connecting vacuum seal opened and the container is introduced into the case hardening chamber, where during the passage of the container the chamber heats the workpieces in the batch to the operating temperature and at the same time the workpieces are saturated with carbon. After the The workpieces get into the cooling zone after a complete cycle of case hardening via the vacuum seal in the zone of accelerated cooling in the inert gas medium and then get into the discharge chamber.

The construction of the known furnace does not ensure the training a uniform insert layer, because the workpieces in the container during the heating of the batch at different temperatures with carbon be saturated differently, i.e. to different depths. Also requires this furnace construction has a high consumption of carburizing gas and electrical Energy, as the entire furnace chamber is filled with reactive gas.

A pusher furnace is also known (SU copyright certificate No. 601317 C 21 D 9/00, 1978), which has a loading, a discharge, a heating chamber, an intermediate chamber with heating elements, which with the help of a holder on a pushing device is attached, which allows a movement of the intermediate chamber in the vertical direction, and a cooling chamber.

The furnace is operated as follows. The workpieces to be treated are loaded onto pallets. The respective pallet is placed in the loading chamber set up.

After opening a slide, it is pushed by the pusher inserted into the heating chamber for a predetermined time. After that, the The next pallet was brought into the furnace. Gradually arrives at the considered Pallet by warming it through after each impact as it is passed through the intermediate chamber. When the intermediate chamber is lowered, the pallet enters the Treatment temperature zone. Brings after the required residence time has elapsed the pushing device returns the intermediate chamber to its starting position; the pallet with the work piece is held for a certain period of time and then by the pusher brought into the cooling chamber. The pallet moves into the cooling chamber the discharge chamber. Then the process repeats itself.

The construction of the intermediate chamber, which is attached to the pusher can be used to carry out the chemical-thermal treatment process in a vacuum required airtight and gas-tight closure of the technological It is difficult to guarantee the chamber. Furthermore, the furnace structure is enhanced by its presence a movable chamber complicated.

Finally, a continuous electric furnace is used for chemical-thermal Treatment of workpieces known (SU copyright certificate No. 456569, F 27 B 9/22, 1976), one chamber for the heating of workpieces with different heat zones, a separate, thermally insulated technological high-temperature chamber, which with one Chamber for the vertical feed of the workpieces is connected, and a cooling chamber includes.

Thereby are the exheating chamber, the chamber for the vertical feed of the workpieces in the technological chamber and the cooling chamber in one line arranged while the technological chamber is outside the line of continuous Horizontal feed of the workpieces is located.

The operation of the furnace is as follows. The ones in the heating chamber Coming containers with workpieces move along the chamber and become gradually.

warmed through. Then they reach a specified temperature heated workpieces into the chamber for vertical feed, from which they are technological Chamber are supplied in which the treatment of the workpieces when required Temperature takes place.

After treatment in the technological chamber, the containers are lowered with the workpieces and moved further into the cooling chamber.

The construction of the known furnace does not see any for implementation the process of chemical thermal treatment necessary airtight and gas-tight Completion of the technological chamber before.

The invention is based on the object of a continuous electric furnace for the chemical-thermal treatment of steel parts to create it through introduction of components and their. mutual arrangement and cooperation, the one Attenuation of the influence of the temperature field on the sealing elements of the furnace During the technological process, it allows an air-tight and gas-tight Diploma the technological chamber during the chemical-thermal treatment process of steel parts and, consequently, technological possibilities of the furnace to expand, to reduce the consumption of saturation gas and electrical energy and to improve the quality of treatment of the steel parts.

The task at hand is ae for an electric furnace; in the patent claim Assumed construction is solved in that the chambers for heating and cooling of the steel parts on the side of the chamber for the vertical feeding of the steel parts have retractable stops and heat shields and their floors horizontally and are made movable and that the bottom of the technological chamber with a vacuum seal is provided, which separates the technological chamber from the others Separates the chambers of the furnace during the chemical-thermal treatment of the steel parts.

By introducing the components mentioned and their mutual Arrangement and interaction in the continuous electric furnace for the chemical-thermal Treatment of steel parts makes it possible to achieve an airtight and gas-tight seal the technological chamber during the chemical-thermal treatment process to ensure the thermal characteristics of the furnace and consequently the uniformity to improve the heating of the steel parts, which ultimately improves the Treatment quality of the steel parts and to reduce the cost of treatment the steel parts leads.

In the following the invention is based on the description of a specific embodiment and the drawings, in which shows: Fig. 1 a continuous electric furnace for the chemical thermal treatment of steel parts according to the invention; Fig. 2 is a section through this electric furnace along line II-II of Fig. 1; and FIG. 3 shows a diagram of the movement of steel parts in the course of the process the chemical-thermal treatment according to the invention.

The continuous electric furnace for chemical-thermal treatment of steel parts has a housing 1 in which a heating chamber 2, a cooling chamber 3 and a technological chamber 4, which is supplied with a chamber 5 for the vertical is connected by steel parts 6, are arranged. The heating chamber 2 consists made of ceramic refractories. The bottom 7 of the heating chamber 2 is with a Device 8 for moving the floor 7 connected. On the loading side the heating chamber 2 is a device 9 for moving the steel parts 6. On the end face facing the chamber 5 for the vertical feeding of the steel parts 6 of the heating chamber 2 are an extendable stop 10 and a heat shield 11 arranged.

The cooling chamber 3 is also made of ceramic refractory materials built up. The bottom 12 of the cooling chamber 3 is provided with a device 13 for whose Movement connected. At the chamber 5 for the vertical feed of the steel parts 6 facing The front of the cooling chamber 3 is an extendable stop 14 and a heat shield 15 provided.

The technological chamber 4 is constructed from raw graphite materials. The bottom 16 of the technological chamber 4 is provided with a vacuum seal 17, which is connected to a device 18 for its movement and during the chemical-thermal Treatment of steel parts 6 the technological chamber 4 from the other chambers 2, 3 of the furnace.

In Fig. 2 is a section through the arrangement of FIG. 1 according to the Line II-II shown, from which the mutual arrangement of the heating chamber 2 and the technological chamber 4, the construction of the heat shields 11 (Fig. 1), the attached to a shaft 20 rotating relative to pin 21 by means of cantilever supports 19 the construction of the movable floor 7 of the heating chamber 2 is made moved on guides 22 with the help of rollers 23, and the arrangement of heating elements 24 can be seen in the technological chamber 4.

The operation of the continuous electric furnace to the chemical-thermal Treatment of steel parts is as follows.

In the heating chamber 2 (Fig. 1) steel parts are successively 6 entered, which with the aid of the device 9 along the furnace over the floors 7, 12, 16 be moved. At the moment of the movement of the steel parts 6, the floors 7, 12, 16 are in a position shown in FIG. 3a; included the steel part Ei is from the floor 7 to the floor 16 and the steel part 611 from the floor 16 moved to the floor 12 (Fig. 3b). Thereupon the floor 7 moves (Fig. 3c) in the left end position, the bottom 12 in the right end position and the bottom 16 in the upper layer.

The stops 10, 14 are extended; the floors 7 and 12 move into the intermediate layer (Fig. 3a), and the steel parts 6 are with the help of the stops 10 and 14 held in the positions shown in FIG. 3c.

The heat shields 11 and 15 (Fig. 1) are then closed. Of the Bottom 16 lifts the steel part 6 into the technological chamber 4, whereby it of seals off the rest of the furnace chamber in an airtight and gas-tight manner. After the end of treatment of the steel part 6 in the technological chamber 4, the bottom 16 is converted into the position shown in FIG. 3a lowered position shown. The device 9 finally moves the steel parts 6 one more step, after which the cycle repeats itself.

When carrying out a chemical-thermal treatment of steel parts, for example vacuum case hardening, in the electric furnace the steel parts 6 in the heating chamber 2 preheating under vacuum or in a neutral gas subjected to reduced pressure. In the technological chamber 4 takes place.

Case hardening in an atmosphere of gases containing carbon. During this time, the reaction gas filling the technological chamber 4 can be repeated several times can be changed by periodically pumping it out and introducing fresh amounts of gas will. In the cooling chamber 3, the steel part 6 is allowed to diffuse for a while held and the other required heat treatment under vacuum or exposed in a neutral gas. Discharge of the steel parts 6 from the electric furnace takes place in the position of the bottom 12 shown in FIG. 3c.

The set object is achieved by the arrangement according to the invention. The use of the stops 10 and 14 (Fig. 1) and the heat shields 11 and 15 allows it, the influence of the temperature field on the sealing elements of the vacuum seal 17 of the furnace during the genetic process to weaken the evenness to increase the heating of the steel parts 6 and the consumption of electrical energy to lower. The possibility provided according to the invention of an airtight and gas-tight Closing the technological chamber 4 allows the technological possibilities of the electric furnace, the electrical energy consumption per 1 ton of manufactured Reduce products by 1.5 to 2 times and reduce the consumption of reaction gas to decrease 8 to 10 times. The electric furnace in the embodiment according to the invention also enables various chemical-thermal processes to be carried out while achieving a high quality of the steel parts 6. When operating the electric furnace there are no leaks of harmful gas admixtures, so that the production conditions generally be improved.

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Claims (1)

Continuous electric furnace for the chemical-thermal treatment of Steel parts Patent claim: Continuous electric furnace for chemical-thermal Treatment of steel parts, a heating chamber (2) for steel parts (6), a Cooling chamber (3) for steel parts (6) and a chamber (5) for vertical feed the steel parts (6) in a technological chamber (4), the chamber (5) for the vertical feeding of the steel parts (6) into the technological chamber (4) in a line between the chambers (2, 3) for heating and cooling the steel parts (6) with the formation of a continuous horizontal feed of the steel parts (6) is arranged and the technological chamber (4) mj.t the chamber (5) for the vertical feed the steel parts (6) is connected, thereby g e k e n n n z e i c h n e t that the Chambers (2, 3) for heating and cooling the steel parts (6) on the side of the chamber (5) for the vertical: kalzuführ the steel parts (6) extendable Have stops (10, 14) and heat shields (11, 15) and their bottoms (7, 12) are horizontal are designed to be reciprocated and that the bottom (16) of the technological Chamber (4) is provided with a vacuum seal (17), which the technological Chamber (4) from the other chambers (2, 3, 5) of the furnace during the chemical-thermal Treatment of the steel parts (6) separates.