Vacuum furnace with water quenching

Abstract

The present invention relates to a vacuum furnace with water quenching, comprising a loading and unloading chamber with a transport mechanism, a vacuum heating chamber equipped with thermal insulation and a graphite heating system, and a quenching chamber, wherein all the furnace chambers are separated with vacuum-tight doors, characterized in that the central chamber of the furnace is a loading and unloading chamber (1) in which there is a transport mechanism (4), a vacuum pumping system (12) and heat radiators (11) for the rapid removal of water and moisture from the charge following the quenching process, to which loading and unloading chamber (1) is adjoined by a vacuum heating chamber (2) on one side, and a water quenching chamber (3) on the other side, wherein a heater (9) and a water agitator (10) are mounted in the water quenching chamber (3) to allow for the regulation of the quenching water temperature, and also an immersion device (7) for immersing the charge in water and a vacuum pumping system (13).

Description

[0001] The present invention relates to a vacuum furnace with water quenching, designed for the heat treatment of metals and alloys necessitating rapid quenching. Vacuum heat treatment devices heat the charge in a vacuum, thereby preventing surface oxidation, and then cool the charge in an atmosphere of inert gases including nitrogen, argon, or helium, or in dedicated quenching oils. Furnaces featuring oil quenching generally include a separate, sealed quenching chamber with an integrated oil tank for quenching. Other known approaches utilize baths containing salt or polymer solutions for quenching.

[0002] The patent document CN216107091U describes a modular vacuum heat treatment production line that includes several dedicated modules for performing different operations within a single apparatus, such as quenching in gas, oil, water, or brine. The line includes a hot material transfer module and a cold material transfer module, with the operating modules positioned on either side of these transfer modules.

[0003] The patent document CN213835455U describes a vacuum hardening furnace with temperature regulation and control, featuring a furnace body whose interior is protected by a heat-insulating plate, thus forming a heating chamber and a quenching chamber. The quenching chamber features a tank containing a quenching medium at its bottom, which is cooled by an external circulation cooling device. The circulating cooling device comprises a circulation pipeline, a heat exchanger, a heat exchange pipeline, and a chilled water unit. A circulation pipeline connects the heat exchanger to the interior of the quenching tank, creating a closed loop. The circulation pipeline connects to the circulation pump and the first group of valves, which controls the connection or disconnection of the pipeline. The chilled water unit is connected to the heat exchanger via a heat exchange pipeline, forming a loop. The heat exchange pipeline connects to the water pump and the second set of valves, which controls the connection or disconnection of the pipeline. A temperature measuring element is placed in the quenching tank and is connected to a programmable logic controller (PLC) located within the furnace body. In addition to the temperature measuring element, the PLC is connected to the first valve group, the second valve group of the chilled water unit, and the heat exchanger.

[0004] With its high cooling capacity, water serves as an effective quenching medium for carbon and low-alloy steels, even those exhibiting low hardenability. A limitation of water as a quenching medium is its propensity for high reactivity with the surface of the metal workpiece. Furthermore, the high volatility of water leads to contamination of the protective atmosphere or hinders achieving the required vacuum level in the furnace.

[0005] The present invention seeks to provide a vacuum furnace design for the heat treatment of metals and alloys requiring rapid quenching, integrating the benefits of vacuum treatment and water quenching without the limitations previously described.

[0006] The vacuum furnace with water quenching comprises a loading and unloading chamber with a transport mechanism, a vacuum heating chamber equipped with thermal insulation and a graphite heating system, and a quenching chamber, all separated by vacuum-tight doors. The vacuum furnace with water quenching is characterised in that it features a central loading and unloading chamber. This chamber is equipped with a transport mechanism, a vacuum pumping system, and heat radiators for the rapid removal of water and moisture from the charge following the quenching process. A vacuum heating chamber is located on one side of the loading and unloading chamber, and a water quenching chamber on the other. The water quenching chamber is equipped with a heater and a water agitator to control the quenching water temperature, as well as an immersion system for the charge and a vacuum pumping system.

[0007] Preferably, a protective atmosphere is maintained in the quenching chamber - inert gas or vacuum.

[0008] The vacuum furnace of the present invention facilitates heating the charge in a controlled protective vacuum and intensive water quenching within a single device, thereby minimizing the detrimental oxidation of the charge surface.

[0009] The invention is explained in more detail with reference to the accompanying drawings, in which Fig. 1 is a schematic cross-sectional view of a vacuum furnace with water quenching; Fig. 2 is a cross-sectional view of an embodiment of a vacuum furnace with water quenching; and Fig. 3 is a cross-sectional view of the water quenching chamber of the furnace.

[0010] The vacuum furnace with water quenching contains three chambers, separated by tight vacuum-tight doors 8. The central chamber is the loading and unloading chamber 1, which is equipped with a transport mechanism 4, a vacuum pump system 12 and heat radiators 11 for the rapid removal of water and moisture from the charge following the quenching process On one side of the loading and unloading chamber 1 there is adjoined a vacuum heating chamber 2 equipped with graphite insulation 5, a graphite heating system 6 and a vacuum pump system 14 enabling the heating of the charge in a protective vacuum atmosphere, and on the other side there is a water quenching chamber 3. A heater 9 and water agitators 10 are installed in the water quenching chamber 3 to regulate the quenching water temperature, as well as an immersion system 7 for transporting the charge and a vacuum pumping system 13, wherein a protective atmosphere, a vacuum or an inert gas atmosphere is maintained in the quenching chamber.

[0011] In a vacuum furnace with water quenching, the charge is heated under vacuum, which provides a protective atmosphere. Subsequently, all furnace chambers 1, 2, 3 are purged with an inert gas, such as nitrogen or argon, before the charge is transported to the water tank within the quenching chamber 3 by a transport mechanism 4. In the quenching chamber 3 the charge is immersed in water by means of an immersion system 7. The charge is rapidly quenched in water and then, after the water has drained, it is transported in a protective gas atmosphere to the loading and unloading chamber 1 for rapid removal of residual moisture. In this phase of the process, the loading and unloading chamber 1 acts as a vacuum dryer. A vacuum pumping system 12 evacuates the gaseous atmosphere, and then the heat emitters 11 are activated, ensuring rapid drying of the load from residual water and moisture. After drying the charge, the transport chamber is purged with gas, and the charge is ready for unloading.

Claims

1. A vacuum furnace with water quenching, comprising a loading and unloading chamber with a transport mechanism, a vacuum heating chamber equipped with thermal insulation and a graphite heating system, and a quenching chamber, wherein all the furnace chambers are separated with vacuum-tight doors, characterized in that the central chamber of the furnace is a loading and unloading chamber (1) in which there is a transport mechanism (4), a vacuum pumping system (12) and heat radiators (11) for the rapid removal of water and moisture from the charge following the quenching process, to which loading and unloading chamber (1) is adjoined by a vacuum heating chamber (2) on one side, and a water quenching chamber (3) on the other side, wherein a heater (9) and a water agitator (10) are mounted in the water quenching chamber (3) to allow for the regulation of the quenching water temperature, and also an immersion device (7) for immersing the charge in water and a vacuum pumping system (13).

2. The vacuum furnace with water quenching according to claim 1, characterised in that a protective atmosphere is maintained in the quenching chamber (3), said atmosphere being an inert gas or a vacuum.

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