NITRIDING OF 2205 DUPLEX STAINLESS STEELS TO ENHANCE CORROSION RESISTANCE

• Main Author: Mohd Azmi, Muhamad Aizat Syafiq
• Format: Final Year Project
• Language: English
• Published: IRC 2016
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://utpedia.utp.edu.my/16878/1/FYP%202%20Dissertation.Aizat.16296.Final.pdf; http://utpedia.utp.edu.my/16878/

Nitriding process had become favorable surface heat treatment in order to improve the corrosion resistance by case hardening process on the material. The case hardening is produced by diffusion of nitrogen and precipitation of the nitride layer on the surface of material. Due to high alloying element, duplex stainless steel shows complex precipitation behavior by forming different intermetallic phase which reduce corrosion resistance in harsh environment such as high temperature in seawater, carbon dioxide and hydrogen sulphide environment. Thus, high temperature gas nitriding process is introduced. In this project, the high temperature gas nitriding process was conducted on 2205 duplex stainless steel at 1200°C for 8 hours and subjected to re-heating at temperature of 700°C to prevent the effect of sensitization. The corrosion resistance is analyzed by immersion test using weight loss method. The samples are subjected to metallographic process to investigate the effect of microstructure after nitriding process using optical microscopy (OM) and scanning electron microscopy (SEM). The uniformity of nitrogen diffusion is identified by using energy dispersive spectroscopy (EDS) on SEM.