CORROSION BEHAVIOUR OF NICKEL BASED SUPER ALLOY HAYNES 230 AND ITS WELDMENT

摘要

In recent days, coal based power industries are looking for increasing the efficiency using the technology called advanced ultra supercritical technology (AUSC). This technology is based on increasing the working temperature and pressure upto 700℃ and 300 bar, respectively. Based on the working conditions of AUSC, there is a need to use newer materials viz austenitic materials like stainless steels and nickel based super alloys. In this paper, a nickel based super alloy called "Haynes 230" is taken up for studying its corrosion characteristics using GTAW process. For the GTAW process, continuous current (C-GTAW) and pulsed current mode (P-GTAW) were used. Two types of filler metals, IN 617 and IN 625 were used. The welded samples were evaluated for the corrosion properties. Corrosion behaviour was evaluated using immersion test, intergranular corrosion test and electrochemical corrosion test as per ASTM Standard.