The heavy-duty NX Pit is the flagship of our range of nitriding / nitrocarburizing furnaces with good reason. Its innovative design incorporates multiple controlled heating zones that ensures the best temperature uniformity inside the retort, typically +/-5°C (9°F) or better. NX furnaces are built for fast heat-up rates and uniform temperature throughout the load.

To discuss your nitriding and nitrocarburizing furnace requirements, fill out our request a quote form

Model Diameter Height Load Capacity
NX-615 23½”(600 mm) 59″(1500 mm)

2200 lbs (1000 kg)
NX-620 23½”(600 mm) 78¾”(2000 mm) 2600 lbs (1200 kg)
NX-815 31½”(800 mm) 59″(1500 mm) 3300 lbs (1500 kg)
NX-820 31½”(800 mm) 78¾”(2000 mm) 3850 lbs (1750 kg)
NX-825 31½”(800 mm) 98½”(2500 mm) 4400 lbs (2000 kg)
NX-1015 39″(1000 mm) 59″(1500 mm) 4400 lbs (2000 kg)
NX-1020 39″(1000 mm) 78¾”(2000 mm) 5500 lbs (2500 kg)
NX-1025 39″(1000 mm) 98½”(2500 mm) 6600 lbs (3000 kg)
NX-1215 47¼”(1200 mm) 59″(1500 mm) 6600 lbs (3000 kg)
NX-1220 47¼”(1200 mm) 78¾”(2000 mm) 8400 lbs (3800 kg)
NX-1225 47¼”(1200 mm) 98½”(2500 mm) 9900 lbs (4500 kg)
NX-1230 47¼”(1200 mm) 118″(3000 mm) 11570 lbs (5250 kg)
NX-1625 61″(1550 mm) 98½”(2500 mm) 13200 lbs (6000 kg)
NX-1630 61″(1550 mm) 118″(3000 mm) 15400 lbs (7000 kg)
NX-1635 61″(1550 mm) 137¾”(3500 mm) 17600 lbs (8000 kg)
NX-1645 61″(1550 mm) 177″(4500 mm) 22000 lbs (10000 kg)

NOTE: Nitrex reserves the right to make changes without notice
For non-standard sizes, please contact Nitrex

  • Inconel 600 (refractory steel) retort and racking for long service life and non-reactive interaction with nitriding atmosphere.
  • Uniform temperature distribution obtained through independently controlled heating zones and intensive atmosphere circulation ensuring full control of nitriding potential in all stages of the process.
  • Light ceramic fiber insulation, reducing heat losses and thus energy consumption.
  • Kanthal long lasting heating elements.
  • Integrated cooling systems.
  • Larger furnaces may be equipped with a ‘Turbo’ cooler, for accelerated cooling of the load. This option is used where productivity is a major issue.
  • Preconfigured & factory-tested
  • Pre-tested for metallurgical results
  • Fully automated operation guarantees repeatable and consistent results
  • True Nitriding/Nitrocarburizing Process Control – Compliant with specifications AMS 2759/10 and AMS 2759/12
  • Superior case properties per customer specifications
  • Various case configurations possible
  • Repetition of results
  • System for data archiving and reporting as well as remote diagnostics
  • Scada connectivity
  • Clean, environmentally friendly processes powered by Nitrex effluent neutralizers

The Nitrex process control system is a product of extensive R&D in process automation and enables accurate process execution and consistency of results. The entire nitriding /nitrocarburizing process is executed in an automatic, self-adjusting and operator independent manner.


This expert system monitors and responds to changes in nitriding conditions by regulating 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 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



With our ‘set & forget’ process, the user selects the desired recipe from a library of researched and tested recipes and initiates a process. From there, all stages of the nitriding cycle (e.g., purge, heat, process control, and cool) are automatically carried out sequentially in one uninterrupted cycle, without further operator intervention. This set-up provides a high degree of accuracy in process execution, contributing to consistency in nitriding / nitrocarburizing results.



  • Nitreg® Potential-Controlled Gas Nitriding
  • Nitreg®-C Potential-Controlled Gas Nitrocarburizing
  • Nitreg®-S Potential-Controlled Gas Nitriding with In-Process Activation for Stainless Steels
  • Nano-S™ Potential-Controlled Gas Nitriding for Stainless Steels (with better corrosion resistance)
  • ONC® In-Process Post-Nitriding or Post-Nitrocarburizing Oxidation
  • Phase-Controlled Gas Nitriding and Nitrocarburizing
Assures a clean, environmentally friendly process
Economical and safe
supply of dissociated
Internal accelerated cooling system to reduce cooling time by 40% or more.
Recirculates clean cooling
water to prolong the longevity of furnace elements.
Easy-to-assemble Inconel
baskets and trays constructed for safe and easy loading
provides a controlled, stable supply of clean water to the cooling coils of the furnace’s accelerated cooling internal heat exchanger