Nitriding Process Temperature Trending Using a Data Logger


Last November, CAS DataLoggers supplied the industrial data logging solution to Northeast Coating Technologies in Kennebunk, Maine. NCT is a surface treatment company specializing in Salt Bath Nitriding Melonite QPQ among other processes to produce high-durability metal components including piston rods, axles and more. Engineer Conrad Woodman is using our dataTaker DT80 Intelligent Data Logger to continually monitor NCT’s production Melonite® line, specifically the salt bath area. The dataTaker is recording tank temperature from multiple thermocouples and using these readings to trend the run data to prove best practices to customers.

The MELONITE® QPQ process forms a nitrocarburized layer around components comprised of an outer compound layer (iron, nitrogen, carbon and oxygen compounds) and a diffusion layer underneath. Initially the process preheats components to raise their surface temperature before they’re placed in a tank containing liquid Melonite salt (MEL 1/TF 1 bath) to start the nitrocarburizing process. Alkali cyanate is the active constituent in the salt bath, and this step is regulated at 896-1166°F with a standard temperature of 1076°F. The components react with the salt and start to diffuse nitrogen and carbon into the substrate. After a preset period of 1-2 hours the components have the proper compound layer thickness and case depth. After immersion in the salt bath, the components are placed in a cooling bath (AB 1 bath) maintained at 700 – 800°F for oxidative treatment which forms a magnetite layer on the components to improve corrosion resistance.

Tank temperature is the treatment parameter NCT needed to monitor and trend for each of its 3 Melonite salt tanks and the AB 1 oxidizing bath tank. With this in mind CAS DataLoggers provided the facility with a Series 3 dataTaker universal data logger to automate their data collection.

CAS DataLoggers Applications Specialist Pat Picciano comments, “The dataTaker’s software is internal so everything this application needs is there in the dataTaker unit itself. Now they have the memory, the data trending capability and the alarming feature. That’s why the DT80’s our workhorse.”

For more information on the dataTaker DT80 Intelligent Universal Data Logger, or to find the ideal solution for your application-specific needs, contact a CAS Data Logger Applications Specialist at (800) 956-4437 or visit the website at