Article

Sanat Sanjay Jambhalekar, NBN Sinhgad School of Engineering, Ambegoan Bk, Pune; Yogesh Sanjay Khawale ,NBN Sinhgad School of Engineering, Ambegoan Bk, Pune; Suraj Shriram Kale ,NBN Sinhgad School of Engineering, Ambegoan Bk, Pune; Sanjog Chandrakant Jagadale ,NBN Sinhgad School of Engineering, Ambegoan Bk, Pune; Prof. V. H. Patil ,NBN Sinhgad School of Engineering, Ambegoan Bk, Pune

Nitriding is a case hardening thermo-chemical process used in many applications today. Nowadays, the improvement of ferrous materials performance is a problem of high interest. One of well known wear and corrosion properties improving technique is plasma nitriding, in which elemental nitrogen is introduced to the surface of a metal part for subsequent diffusion into the material. As a result, a compound, “white” layer and a diffusion zone are formed at the surface. A literature research was done in order to study the nitriding mechanism and different nitriding methods used in industry. This paper is related to piston rod porosity defect. Porosity i.e. small pits are ocurred on piston rod surface after plamsa nitriding. The material used here is AISI 4340 steel. Plasma nitriding of alloy steel, grade AISI 4340, was carried out at different temperatures, keeping other processing parameters constant. But defect is not reduced. So alternative methods, materials, defect minimization techniques,defect causes & its minimization are discussed in this paper. The experiments were carried out on piston rod samples which were plasma nitrided with formation of varying amount of thickness of compound white layer and maintaining diffusion layer depth the same. The characterization of samples was done in respect of chemical composition, microstructure & micro-hardness. The characterization of the plasma nitride samples was carried out using different analysis techniques X-ray diffraction, SEM. Metallographic and chemical analysis were done in order to determine the influence of microstructure defects on the hardness plasma nitrided steel in industrial conditions. The microstructure was observed by optical microscope before and after each nitriding method. The hardness of specimens was measured before and after each treatment. The effect of temperature on the surface roughness, hardness, and microstructure was investigated along with their corrosion resistance.