窒化反應과 炭化反應이 同時에 일어나는 가스窒炭法은 570℃에서 3時間동안 50% 암모니아와 50% endothermic 가스雰圍氣에서 處理한 다음 油中에 quenching하며 軟鋼의 表面에 18μ 두께의 化合物層을 形成한다. 이 層의 組織은 主로 C. P. H. ε-carbonitride와 若干의 γ`-Fe₄N 및 α-Fe로써 構成되어 있음이 X-線回折試驗에 依하여 밝혀졌으며 化學分析實驗에 依해서 이 層의 C/N比는 0.21이며 C+N 量은 29.5 atm. %로써 이는 ε-carbonitride 相域의 下限界에 가깝다.

The gaseous nitrocarburizing treatment involves the simultaneous nitriding and carburizing at 570℃ in an atmosphere of 50% ammonia and 50% endothermic gas for a period of three hours followed by oil quenching. The treatment produces a compact compound layer 18μ thick on the surface of mild steel. X-ray structural analysis has revealed that this layer consists mainly of the C. P. H. epsilon carbonitride phase together with some Fe₄N and free ferrite chemical analysis has been used to show that C/N ratio in the layer is 0.21 and that it contains a total interstitial content of 29.5 atomic percent, which is close to the lower limit of the ε-carbonitride phase field.