Plasma nitriding has been extensively used to improve materials’ surface and mechanical properties using conventional plasma techniques. However, this process generally results in a nonuniformity of the properties. In the cathodic cage plasma nitriding (CCPN), the plasma is active only on the surface of the cathodic cage, eliminating inherent defects of conventional plasma nitriding. Herein, a duplex treatment, CCPN and TiN deposition, is used on SINTER30 tool steel for the first time. Vickers microhardness tests, X‐ray diffractometry, Raman scattering spectroscopy, and scratching tests characterize the samples. The results show that TiN post‐coating attains higher surface hardness. All the groups increase their microhardness properties when compared with nontreated substrates. The prior treatment of plasma nitriding assists hardening of the substrate surface. The best condition is obtained when the sample is placed inside the titanium cage and positions directly on the sample port, with simultaneous duplex treatment. When the substrate passes through this simultaneous duplex process, peaks corresponding to Fe3N and TiN are observed at Raman spectra. Suitable TiN layers improve the film adhesion, which is correlated to the system's load‐bearing capacity.