Ferritic Nitrocarburizing

System precision delivers hardness, durability and corrosion control.

Ferritic nitrocarburizing is a case-hardening technique that uses heat, nitrogen and carbon to toughen up the exterior of a steel part, improving its durability, appearance and corrosion resistance.

Ferritic nitrocarburizing is an effective, economical case-hardening option for a broad range of parts, including:

  • Drive train parts like crankshafts, camshafts, piston rods and gears for cars, trucks and heavy equipment
  • Firearms components like barrels and slides
  • Dies for manufacturing processes

Case hardening treats a metal surface to create a hard external “case” while preserving the strength and flexibility of the underlying metal.  There are dozens of ways to case harden a metal; how you do it depends on how you need the finished metal to perform.

Some case-hardening techniques heat a metal to such extremes that it takes on new chemical properties. At that point, the metal can be manipulated to create steel parts hard enough to cut through concrete or softer grades of steel. Unlike many case hardening techniques, though, ferritic nitrocarburizing occurs while the steel is in a ferritic phase, as opposed to an austenitic phase. This helps to avoid some of the issues that arise with inducing phase changes in steel, such as distortion.

Ferritic nitrocarburizing is a good option for improving the appearance of a part, increasing its resistance to scratching and adding a layer of corrosion resistance. It’s often used in many bearing, cast, forge and tooling applications.

A closer look at the ferritic nitrocarburizing process

Ferritic nitrocarburizing works like this: A furnace heats a steel part to a precise temperature that will allow a surface layer to become diffused with nitrogen and carbon atoms. The exact temperature depends on how the part will be used, but it’s typically between the relatively low temperatures of 950 degrees Fahrenheit and 1100 degrees Fahrenheit. These temperatures are low enough to prevent problems often associated with higher temperatures, such as distortion, while still allowing carbon and nitrogen to dissolve through the surface of the steel.

The furnace uses computerized controls to apply precise amounts of nitrogen and carbon at an exact temperature. Ferritic nitrocarburizing has become much more popular in recent years because computerized controls can ensure the exacting precision needed to treat specific parts in highly specific ways.

The next step in the ferritic nitrocarburizing process is quenching: cooling the part to lock the iron, nitrogen and carbon atoms at the surface into place. After the part cools, its exterior is harder and more durable. It’s much tougher to dent it, scratch it or corrode it.

Another advantage of ferritic nitrocarburizing is that it preserves the shape of a part. Hardening techniques that use much more heat can cause distortions that have to be corrected, creating an extra step in the case-hardening process. Avoiding this distortion makes nitrocarburizing a more practical and economical hardening option.

Paulo’s approach to ferritic nitrocarburizing

At Paulo, our ferritic nitrocarburizing process:

  • Improves a part’s physical appearance
  • Lengthens a part’s lifetime by reducing wear
  • Reduces the risk of scuffing and scratching
  • Fends off corrosion
  • Limits distortion

We have decades of experience in all phases of heat treating and case hardening. We also have a broad array of furnaces and treatment techniques ensuring we can treat parts over a wide range of sizes and shapes.

Heat treating 101: An introduction to heat treating procedures