A surface treatment company specializing in salt bath nitriding Melonite QPQ — among other processes,Northeast Coating Technologies in Kennebunk, Maine, produces high durability metal components, including piston rods and axles. Engineer Conrad Woodman uses a dataTaker DT80 from CAS DataLoggers, Chesterland, Ohio, to continually monitor NCT’s production Melonite QPQC line, specifically the salt bath area. The dataTaker records tank temperature from multiple thermocouples, and the engineering staff uses these readings to trend the run data to prove best practices to customers. 

NCT’s Melonite QPQ process forms a nitrocarburized layer — composed of an outer compound layer (iron, nitrogen, carbon and oxygen compounds) and a diffusion layer underneath — around components. Initially, the process preheats components to raise their surface temperature before they are 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 to 1166°F (480 to 630°C) with a standard temperature of 1076°F (580°C). The components react with the salt and start to diffuse nitrogen and carbon into the substrate.

After a preset period of one to two 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 to 800°F (371 to 427°C) for oxidative treatment, which forms a magnetite layer on the components to improve corrosion resistance.

Tank temperature is the treatment parameter that NCT needed to monitor and trend for each of its three 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 datalogger to automate data collection.


Conrad Woodman installed the datalogger in a control cabinet located about 30 feet away from the salt bath tanks. For future expansion, the panel size is large enough to add a touchscreen PC running Windows 7 embedded in the face of the control panel. Another junction box is set up between the tanks and the datalogger where the cables run.

Temperature Sensors

Northeast Coating Technologies is currently collecting temperature data from four Type K thermocouples. All four sensors run to different tanks in the same area — three sensors take readings from each of the three Melonite tanks, and one sensor goes to the oxidizing tank. In the future, NCT may use a dataTaker CEM20, a channel expansion module, and run thermocouples from the oven and degreaser tank to the datalogging setup, enabling them to cover six monitoring points using the same system.

Using multiple schedules, the dataTaker monitors several tanks simultaneously. The standalone logger also has a built-in display and operates reliably using low power.

Data Retrieval

To retrieve the data remotely, the engineering staff at NCT simply inputs an IP address in a web browser when they need to retrieve the temperature data. Woodman has set up a link on the desktop PC located in the nitriding area so users can export the data in CSV format and work with it in Excel. The datalogger can store up to 10 million data points in its user-defined memory, enabling independent control of schedule size and mode so that it can be set up to log only as long as needed. Users also can retrieve data from a flash drive via the datalogger’s USB port.

Email Alarm Notification

The temperature datalogger doubles as an automated alarm system, giving users a quick way to tell if a potentially critical situation is developing. The dataTaker’s email alert feature will notify Woodman and other users if there is an issue with the salt bath. For example, if the tank temperature starts boiling over and threatens to eventually cause a fire, the system will automatically alert the team. The temperature alarm is set to send out an email alert that the process is malfunctioning whenever any tank temperature exceeds 1250°F (677°C). This way, workers are able to take immediate remedial action to prevent damage and delays.

Included Software

Using dataTaker’s DPlot software, users display the data by going into the thermocouple sensor page and converting it into CSV format. Users also can view the high and low range for each sensor. Also, it is possible to open up the native files and plot them into a graph for presentation. The software is included with every CAS datalogger.

Using the company’s dEX software, users can create dashboard dials to view real- time data, create trend charts and tables, and retrieve historical data for analysis. The Windows Explorer-type interface eases navigation. This built-in software runs directly from a web browser and can be accessed locally or remotely anywhere that a TCP/IP connection is available. Both software programs run in Windows 8.

Business Benefits

For Northeast Coating Technologies, the datalogging solution allows the company to prove that the nitriding process achieves a consistent nitride layer on all components. Not only can this single datalogger connect to Type-K thermocouples on all four tanks but it also connects with any sensor to measure nearly any value. The system’s ease of programming and large internal memory gives users an effective data trending solution. That means, NCT can give customers detailed runtime data that shows their best practices. In addition, all of the data is easy to organize and present in Excel. Conrad Woodman explains, “We have the dataTaker logger up and running seamlessly. We had a couple hiccups originally in the programming aspect of it, but we quickly got through them since you don’t have to be an engineer to learn the software. This unit is exactly what we needed for the process we are using it for.”

As a secondary benefit, NCT also can rely on the email alarm feature for additional process overview. Due to its flexible programmability, the dataTaker is setup to track both the runtime and alarming.

Woodman has also received free tech support from CAS DataLoggers over the phone to get the project setup ASAP. Says CAS DataLoggers’ Pat Picciano, an application specialist,“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 is our workhorse.”