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Specialists in Heat Treatment

Process Control

Gas Nitriding Process Control

The gas nitriding process control systems are designed to provide a fully automatic operation. The entire nitriding process is executed in an automatic, self-adjusting and operator independent manner.

Process Control Hardware

A typical system is configured in three distinct sections, which facilitate operation and maintenance of the system. They consist of:

  1. An electronic process control panel with I/O boards, an industrial computer and a color monitor.
  2. A gas control panel with: gas analyzing, flow and pressure measuring transducers, calibration and safety features.
  3. An electric control panel with: one SCR controller for each heating zone, transformers, contactors, fuses, and switches.

This type of set-up provides a high degree of accuracy in process execution, contributing to consistency in nitriding results.

System Features

The Nitrex Process Control System monitors and controls automatically the following parameters and operating functions:

  • Furnace heating functions such as process temperature, and overheat control with automatic emergency procedures.
  • Atmosphere composition and flow for a particular cycle.
  • Nitriding atmosphere ratios.
  • Nitriding Potential Kn (dissociation rate, for customer defined cycles).
  • Temperature for each process stage.
  • Gas pressure inside the retort.
  • Gas recirculation.
  • Execution of the cooling stage and shutdown.
  • Cooling water.
  • Process safety features.

 Process Control

The nitriding process control is carried out in a closed loop circuit. This, coupled with advanced features, enables the process control system to automatically respond to the changes in nitriding conditions, which occur during the process.

To adjust the process parameters, the furnace atmosphere is continuously sampled and analyzed. Based on the data extracted, the process computer adjusts the incoming atmosphere, thus maintaining the preset value of the nitriding potential as accurately as possible.