These universal chamber furnaces with radiation heating have been specifically designed to withstand heavy-duty use in the tool shop. They are particularly useful for processes such as tool making or for hardening jobs, e.g. annealing, hardening and forging. With help of various accessories, these furnaces can be customized to your application requirements.

• Compact, robust design
• Deep furnace chamber with three-sides heating: from both side walls and bottom
• Heating elements on support tubes ensure free heat radiation and a long service life
• Bottom heating protected by heat conducting SiC tiles
• Stainless steel upper door jamb protects furnace structure when furnace is opened hot
• Base frame included in the delivery, N 7/H - N 17/HR designed as table-top model
• Exhaust opening in the side of the furnace, or on rear wall of chamber furnace in the N 31/H models and higher
• Temperature uniformity up to +/- 10 °C according to DIN 17052-1
• Low energy consumption due to multi-layer insulation
• Gas spring dampers provide for easy door opening and closing
• Heat resistant zinc paint for protection of door and door frame (for model N 81 and larger)
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive

We recommend these accessories for applications up to 1100 °C to protect the furnace floor, especially if a charging cart is used.

• Tmax 1100 °C
• Three raised edges
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)
• Larger plates and custom dimensions available upon request

Annealing boxes are made of heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841) and also feature a lid for top charging. A ceramic fiber gasket is inserted in the circular seal profile on the upper edge of the box to seal it. To prevent oxidation during the process, neutral annealing coal is placed in the box. These bind the oxygen in the box. The oxygen inside the box is bound by the coal. After the heat treatment, the box is removed from the oven, the lid is opened using tongs and the workpiece removed. Our annealing boxes are also well suited for brazing. The boxes can also be used with the appropriate granulate for carburizing (also referred to as case hardening or cementing) and for powder nitriding or powder boriding. The workpieces are placed in the box with carburizing granulate or nitriding powder or boriding powder and a suitable activator.

• Tmax 1100 °C
• Annealing box with lid and seal profile
• Lid sealing with ceramic fiber
• Also usable for carburizing and powder nitriding
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)

The annealing boxes for heat treatment under protective gas are equipped with a protective gas intlet and outlet. A box with protective gas is advisable for larger workpieces requiring defined heat treating. We would be pleased to carry out Trials at our technical center can be carried out on request. Up to furnace model N 61/H with downward door opening the gas ductway is laid through the upper section of the door collar, for larger furnaces with upward door opening the supply line is laid through the lower furnace collar. The box is pressurized with non flammable protective and reactive gases such as argon, nitrogen or forming gas via the protective gas tube. There are manual and automatic systems available for protective gas. See pages 74 - 75. for more information about protective gases which can be used as well as manual and automatic protective gas systems. After charging the box it is closed and preflushed outside the furnace. Afterwards the box is placed in the preheated furnace. The quantity of gas can be reduced to the process flush quantity. After the heat treatment the box is pulled out of the furnace, the charge taken from the box and placed in the quenching medium. We recommend using binding wire on the parts so that they can easily be grasped by tongs. A flexible type K thermocouple is installed in the box for measuring the temperature; we recommend connecting it to a digital display device or to a temperature recorder. The box can also be cooled down on a cooling platform while closed. Be sure that the protective gas flowrate is increased for this application.

• Tmax 1100 °C
• For non-combustible protective and reactive gases argon, nitrogen and forming gas (observe national regulations)
• Protective gas box with fiber sealing and lid, gas supply via a tube into the bottom of the box
• Protective gas connection via quick coupling with hose connector (inner diameter 9 mm)
• Piping for gas inlet and outlet through the furnace collar
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)
• Charge thermocouple type K for temperature display or charge control

Additional equipment

• Starting from N 31/H a charging cart is recommended
• Digital temperature display
• Gas supply systems
• Charging forks
• Draw Hook

For heat treatment of bulk goods and hollow parts under protective gas atmosphere we recommend the usage of protective gas boxes with an additional evacuation lid. These boxes are equipped with a lid for top charging, protective gas inlet and outlet as well as a evacuation lid with rubber sealing gasket. Gas ductwork and handling while hot is the same as the protective gas boxes described on page 45. In addition, these boxes also feature a connection for a vacuum pump with a shut-off valve. After charging the box in a cold state it is evacuated and afterwards flushed with protective gas. By repeating this process once or several times the results are considerably improved. After the box was flushed with protective gas the last time, the evacuation lid is removed and the box is placed into the preheated furnace. Protective gas is used for heat treatment. Thus traces of oxygen in the box can be reduced by a considerable amount which improves the quality of the components accordingly. After the heat treatment the box is taken out of the furnace and can be cooled in air or be opened to remove the charge. The box can also be force-cooled on a cooling platform while closed. Be sure that the protective gas flowrate is increased for this application.

• Tmax 1100 °C
• For non-combustible protective and reactive gases argon, nitrogen and forming gas (observe national regulations)
• Protective gas box with fiber sealing and lid with locks, recess for evacuation lid, gas inlet via a pipe into the bottom of the box
• Evacuation lid with rubber sealing (Elastomer) and manometer
• Protective gas connection via threeway ball valve and quick coupling with hose connector (inner diameter 9 mm)
• Piping for gas inlet and outlet through the furnace collar
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)
• Charge thermocouple type K for temperature display or charge control

Additional equipment

• Starting from N 31/H a charging cart is recommended
• Digital temperature display
• Vacuum pump
• Gas supply systems
• Charging forks
• Draw Hook

• Charging forks to charge and remove protective gas boxes up to model N 17/H

For heat treatment of small amounts of bulk material or small parts under protective gases with subsequent fast quenching in oil or water, we recommend to use protective gas boxes with a hinged lid. Boxes with an angled hinged lid on the front are equipped with a protective gas line on the rear wall. The supply line is run through the upper furnace collar. After preflushing the box with non-flammable protective and reactive gases such as argon, nitrogen or forming gas 95/5, the box is placed with hinged lid first into the furnace. Due to a slight overpressure within the box the protective gas is vented off through the hinged lid. After the heat treatment the box is taken out of the furnace and the charge is poured into quenching bath directly out of the box. By placing the box at an angle the hinged lid opens by itself. The contact with ambient air is reduced to a minimum.

• Tmax 1100 °C
• For non-combustible protective and reactive gases argon, nitrogen and forming gas (observe national regulations)
• Protective gas box with flap lid and gas supply from the rear wall
• Protective gas connection via quick coupling with hose connector (inner diameter 9 mm)
• Piping for gas inlet and outlet through the furnace collar
• Lid remains closed through its own weight
• Holder with hand handle
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)
• Charge thermocouple type K for temperature display or charge control

Additional equipment

• Starting from N 31/H a charging cart is recommended
• Digital temperature display
• Gas supply systems

In the case of successive protective gas heat treatment of individual parts, a gassing box is recommended, which remains in the furnace. For charging, the box is equipped with a flap lid to the front. The lid closes without a sealing profile against the oblique position of the box opening. Larger gas losses in comparison with removable boxes can be expected. For the protective gas supply the pipe goes through a bore on the rear wall of the furnace. For charging, the box is opened in the furnace using a draw hook and the workpieces are placed into the box. The box is continuously flushed with non-flammable protective and reactive gases such as argon, nitrogen or forming gas 95/5. Due to a slight overpressure within the box the protective gas is vented off through the hinged lid. After the heat treatment the box is opened using a draw hook and the workpieces are removed.

• Tmax 1100 °C
• For non-combustible protective and reactive gases argon, nitrogen and forming gas (observe national regulations)
• Protective gas box with flap lid and gas supply from the rear wall
• Protective gas connection via quick coupling with hose connector (inner diameter 9 mm)
• Piping for gas inlet and outlet through the rear wall
• Front flap lid which opens downwards
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)
• Charge thermocouple type K for temperature display or charge control
• The furnace will not be equipped with a charging plate (protective gas box is permanently installed)

Additional equipment

• Digital temperature display
• Gas supply systems

When workpieces made of air-hardened steel must be heat treated under protective gas and quenched afterwards, the protective gas annealing bag with holder is an optimal solution. This system consists of a holder with charge carrier and protective gas tube as well as a bag made of stainless steel heat treating foil. The charge is placed on the charge carrier and covered with the protective gas annealing bag. The bag is preflushed with non-flammable protective and reactive gases such as argon, nitrogen or forming gas 95/5 and placed together with the holder in the furnace. After the charge has been heated, the protective gas annealing bag and holder are removed from the furnace and cooled with the help of the forced cooling system or in still air. At the same time the workpiece remains in the bag in the protective gas atmosphere. This prevents oxidation from occuring. Due to thin-walled foil very rapid cooling times can be achieved. The protective gas annealing bag is also suitable for quenching workpieces in oil or water. The protective gas annealing bag with holder is taken out of the hot furnace after the heating time. The bag is pulled off the holder above the quenching bath using a heat protection glove. After this the workpiece can slide directly into the quenching bath. The short exposure to ambient air while being pulled out normally has only minimum effect on the surface oxidation of workpieces. The bags can be used multiple times. Our experience shows that at temperatures < 950 °C the stainless steel heat treating bag lasts for approx. 10 - 15 processes. At temperatures between 950 °C and 1050 °C, use for approx. 5 - 10 processes can be assumed.

• Tmax 1100 °C
• For non-combustible protective and reactive gases argon, nitrogen and forming gas (observe national regulations)
• Holder with protective gas annealing bag
• Supplied with three protective gas annealing bags
• Protective gas supply with quick lock and hose connector (inner diameter 9 mm)
• Protective protective gas through notch in upper furnace collar
• Holder with hand handle
• Heat-resistant alloy 314 (AISI)/(DIN material no. 1.4841)
• Charge thermocouple type K for temperature display or charge control

Additional equipment

• Starting from N 31/H a charging cart is recommended
• Digital temperature display
• Gas supply systems