Pengaruh Perubahan Suhu Nitridasi Plasma Lucutan Pijar DC Terhadap Kekerasan Baja AISI 4140

In this paper, steel material is widely used in industry. According to David Pye et al, steel material still has deficiencies, which are susceptible to corrosive environments such as in the coal industry application so that it quickly wears out. So it is necessary to improve the mechanical properties. The problem to be examined and discussed in this study is the effect of the nitriding of DC incandescent plasma temperature changes on the hardness of AISI 4140 steel. The tests to be carried out are the hardness testing of materials, microstructure testing after the plasma nitriding process. The purpose of this study was to determine the effect of nitriding temperature with variations of 300ºC, 350ºC, 400ºC, 450ºC, 500ºC at a pressure of 1.6 mbar and 3 hours for mechanical properties especially the hardness of AISI 4140 steel after undergoing nitriding process and also to determine the effect nitriding temperature of the microstructure of steel after undergoing a nitriding process. The material treatment method in this study is the method of surface hardening through nitriding by adding nitrogen to the surface of the material. The working principle of the nitriding process is the addition of nitrogen to the surface of the material so that it becomes very hard. Plasma nitriding on steel surfaces with temperature variations proved to produce increased hardness compared to before nitriding, increasing material surface hardness by 51.5% from the base material hardness of 97.8 VHN to 189,975 VHN. But this condition of violence was obtained at a temperature of 450ºC. Testing of microstructure using SEM / EDX shows a thin layer on the outside of the surface. However, the nitrogen element cannot be clearly identified because it is very small. \nKeywords: Steel AISI 4140, Surface Hardness, Plasma Nitriding, DC Glow Discharge Plasma, Micro Structure.