The main reason why controlled nitriding has not been fully popularized in China is that imported nitriding expert controllers are expensive. In fact, most functions of the controller (program, display, alarm, recording) can be realized by general-purpose PLC and touch screen. The core is the nitriding potential measurement and control algorithm. Encapsulating long-term proven algorithms into nitriding expert transmitters allows any instrument or PLC with a control loop to become an expert nitriding controller, which can significantly reduce costs and promote the popularization of controllable nitriding.
- The most important thing is the word "expert": the core is Kn measurement and control algorithm
- General functions (program, HMI, recording) can be realized by PLC + touch screen
- Architecture: hydrogen probe + algorithm transmitter + general PLC/instrument
- Lowers the threshold for renovation, suitable for upgrading old furnaces
- Complete process reports, data records and safety interlocks are still needed
Question: Why is the popularity of controlled nitriding slow?
The advantages of controlled nitriding (with Kn as the control target) have been widely recognized: controllable compound layer, stable quality, and saving ammonia gas. However, many companies are still using the traditional method of "looking at the decomposition rate and manually adjusting ammonia". The main obstacle is cost: the price of a complete set of imported nitriding expert controllers is high, and the return on investment in old furnace renovation is not obvious.
What is the value of a controller?
Taking apart a nitriding expert controller, the functions can be roughly divided into two categories:
| Function | Can it be achieved with general equipment? |
|---|---|
| Process programming and execution | PLC + touch screen can achieve |
| Temperature and flow loop control | PLC/Instrument can realize |
| Data recording, reports, alarms | Common software can achieve |
| nitriding potential measurement calculation and control algorithm | It requires long-term process experience accumulation, which is the core |
Gauss Control expressed the same view on the wind power machinery industry page: most functions of the controller can be realized on general PLCs and touch screens, and the core is the nitriding control algorithm; its German cooperation team has more than 30 years of experience in nitriding control, and has built the algorithm into the nitriding expert system transmitter, so that any instrument or PLC with a control loop can become a nitriding expert controller, thus significantly reducing costs.
Low cost architecture
Hydrogen probe (measure H₂) → algorithm transmitter (calculate Kn, output control signal) → general PLC/instrument (adjust ammonia and dilution gas flow valve) → HMI/software (process, record, report)
advantage:
- The existing PLC and human-machine interface are retained, and the amount of modification is small;
- The core algorithm has been verified to avoid the risk of self-development;
- Low investment and short payback period;
- Can be upgraded furnace by furnace.
What else is needed for a complete package?
- Reliable measurement: Hydrogen probe, flow meter;
- executive agency: Ammonia, dilution gas (N₂ or decomposed ammonia) flow control valve;
- Ammonia decomposer(If you need to use decomposition gas to adjust Kn);
- Craftsmanship and Records: Process preparation, professional production reports, and data records to meet customer and standard requirements;
- safety interlock: Furnace temperature, furnace pressure, ammonia leakage, purging program.
The Gosi Control NITROMATE™-18 official website describes it as a highly integrated controller that can control the entire nitriding process, covering process preparation and execution, medium flow, nitriding index (Kn), temperature, professional production reports, data recording and equipment automation expansion. Users can choose the integrated controller or the "transmitter + existing PLC" method according to their own conditions.
Frequently asked questions
Can the old well-type nitriding furnace be transformed into controlled nitriding?
Most can. Furnace sealing, gas circulation, flow control capabilities and sampling conditions need to be evaluated, followed by the installation of hydrogen probes, flow control and control algorithms.
Is it necessary to re-do process verification after transformation?
need. After changing to Kn control, the expression of process parameters has changed. The layer depth, compound layer and hardness should be verified through samples, and a new process card should be established.
Can a low-cost solution satisfy AMS2759/10?
Compliance depends on the overall system (measurement accuracy, control, recording, calibration) complying with the terms of the specification and not on the controller form. It should be evaluated item by item against the specifications.