QPQ Liquid Nitriding
PLEASE NOTE: Thermex Metal Treating no longer offers QPQ Liquid Nitriding. Thermex has a comparable, more environmentally friendly, lower cost option in Nitrox (FNC with Post Ox).
Please see a breakdown of these processes here.
This page is left available for process understanding and knowledge sharing.
QPQ Liquid Nitriding (also known as salt bath nitriding) is a process for producing a thin, high-hardness case that is wear and corrosion resistant, with little or no distortion of the part during processing.
Process Attributes:
- Lustrous black finish
- Thin, high-hardness case
- Wear and corrosion resistant
- Little or no distortion of the part
Liquid nitriding is suitable for a wide variety of carbon steels, low alloy steels, tool steels, cast irons, and stainless steels.
The resulting lustrous black finish is an effective alternative for both chrome and nickel plating.
Liquid nitriding is suitable for a wide variety of carbon steels, low alloy steels, tool steels, cast irons, and stainless steels. Liquid nitriding is a relatively low-temperature form of case hardening, resulting in minimal part distortion.
Process Selection and Quality Control
Liquid nitriding requires precise control of the treatment process. Thermex operates under an ISO Certified Registered Quality Management System. Process quality control measures include:
- Complete control of process sequence, including salt bath temperature and composition, polishing, and post-treatment parts handling
- Test coupons of matching material are run with all nitriding loads. Coupons can then be used for metallurgical analysis in Thermex’s in-house metals testing laboratory. Random microhardness case depth surveys ensure that process specifications are being met.
- View a sample Case Depth Survey here.
Contact Thermex for more information.
Gas FNC is the modern, environmentally preferred alternative to Liquid Nitriding and offers greater process control, equivalent to better part properties, and lower costs.