Microstructural characterization and mechanical properties of sand cast and investment cast alloy 625 for HP/IP casing applications for advanced fossil fired power plants

Abstract

Alloy 625 is a candidate material for high temperature sections of High Pressure (HP)/ Intermediate Pressure (IP) turbine casings for Advanced Ultra Super Critical (AUSC) power plants. This material is expected to operate at steam temperature of 710°C approx. and pressure of 300 ata approx. After carrying out a detailed literature survey, it was observed that microstructural information and mechanical properties data on Alloy 625 cast material is limited. Hence, this study was undertaken for obtaining of mechanical properties and microstructures at room temperature through two manufacturing techniques namely, conventional sand casting and investment casting. Mechanical properties data includes tensile testing and impact testing. The data obtained from this study is essential for design of casings. The details of the study and results obtained are discussed and presented in this work.