Plasma / ion nitriding — control, distortion, and the parts that need it

Why a 420 stainless mold cavity that gas nitride ruins comes out of a plasma cycle intact, what the four plasma levers actually do, and which parts the process is the correct call for.

10 min readLesson 5 of 12

A Nitralloy 135M precision spur gear, 6-inch pitch diameter, tolerance band on tooth profile 12 µm. The shop sends it for a 60-hour gas nitride cycle. It comes back with a 0.45 mm case, correct hardness traverse, and 28 µm of distortion at the tip diameter. The case is in spec, the gear is out of tolerance, and the next iteration of the same part on the same equipment will produce the same result. The process change required to hold tooth profile within the band is plasma.