Gas Nitriding

Nitriding Heat Treatment for Machined Parts & Stampings

ThermTech provides gas nitriding heat treatment for machined parts and stampings. Gas nitriding is an ideal heat treatment for case hardened machined components with wear surfaces.

It’s also ideal for parts where distortion is a concern due to tight tolerances since distortion is not typical due to the relatively low temperatures involved in the process.


As a top commercial heat treater we offer:

  • Gas Nitriding 4140 (pre-hardened)
  • Gas Nitriding S-7 (pre-hardened)
  • Gas Nitriding H-13 (pre-hardened)
  • Gas Nitriding P-20
  • Gas Nitriding Nitralloy 135M

Selective gas nitriding is possible through the application of nitride stop-off paints.


All of our gas nitriding cycles are ran in one of our batch-type retort furnaces for optimum process & lot control.

All Therm-Tech furnaces are AMS 2750 compliant.

Our largest gas nitriding furnace has a working dimension of 33.5” DIA X 53” Long.

Case Depth

We run a shallow case depth load (0.003”) every night with next day turnaround. We also perform nitriding heat treatment for deeper case depths on a regular basis.

Contact ThermTech Customer Support regarding current lead-times for deeper case depths.

Therm-Tech does not provide gas nitriding services for stainless steels.


The process of case hardening via gas nitriding is performed by heating previously hardened parts in a controlled atmosphere to a temperature below the previous tempering temperature.

Then, the temperature is held for a length of time proportionate to the case depth requirement.

After gas nitride hardening is complete we hand blast the parts using aluminum-oxide blast media in order to remove excess nitride stop-off paint.

Growth in the Gas Nitriding Process is on the order of .0005-.001” all over due to the deposition of the white-layer.


For parts that require the promotion of different properties we recommend carburizing hardening, as well as vacuum carburizing. Both of these heat treating services reduce the need for blasting services after the hardening treatment.

It is highly recommended that we perform the carburizing hardening or vacuum hardening of the rough machined component prior to nitride treatment.

Contact ThermTech to find out if nitride hardening is an ideal heat treatment for your machined parts or stampings.