Equipment Highlights

Hot Wall Temperature Control System
The previous generations of ion plasma furnaces, as well as standard gas nitriders were cold wall systems using plasma to heat the part incorporating single zone temperature controls and used spectrometer methods of measuring part temperature.

The latest developments in plasma furnaces include hot wall technology, pulsed plasma instead of straight D.C. current, and part temperature measurement via the use of thermocouples inserted directly into the parts. These thermocouples can be assigned to a respective zone within the furnace depending on their location.

The hot wall technology and multi zone heating and cooling controls allow for convection heating of the components up to the nitriding temperature, and the temperature of long parts can be measured at the top, middle, and bottom with the automated control system self adjusting to achieve a uniform temperature from top to bottom.

The elevated temperatures normally found in the central part of the recipients in cold wall systems are eliminated with this system. Furthermore different geometries and masses can be run on different levels and with the multi-zone temperature control can be run at the same temperature. This translates to more cost efficient processing allowing different parts to be run on different levels while maintaining consistent and reproducible results.

Non-uniform temperatures lead to inconsistent results in surface hardness, white layer thickness, and case depth; all of which contribute to distortion due to uneven stresses in the part as well as unpredictable performance in the field.

Pulse Plasma Generators
Temperature regulation during the active plasma stages can be attained by both the multi-zone heating/cooling system as well as by the plasma generators through the pause time between pulses, both of which are variable. In addition to the variable frequencies bipolar pulsing is also possible.

Computer Integration and Data Logging
This allows remote control and maintenance over a network through the use of a modem, reliable process control through and independent PLC, PID and cascade controls, and real time data logging of all furnace parameters, including the following:

1. Voltage, Current, and Power Consumption
2. Wall Temperatures on each level
3. Part Temperatures
4. Pressure
5. Plasma Pulse/Pause times
6. Gas flow rates

Many safeguards and alarms protect the parts within the furnace including arc detection and contingencies for any of the above parameters which do not fall within specifications.

These logs are kept as part of the permanent record for the furnace run for an indefinite period of time.

Plasox® Process
This post nitriding process, conducted as an optional integral step in which water is injected into the retort causing oxidation of the surface and forming magnetite (Fe3O4). This process further improves the corrosion resistance, the wear resistance via a drop in the coefficient of friction, and improves the aesthetic appearance.