Microstructural characterization of super duplex stainless steel UNS S32760 after heat treatment in different cooling media

摘要

Ideally, In super duplex stainless steel, there's a 1:1 ratio of microstructure austenite and ferrite phases. However, these phases depends on their composition and thermal history. This study aims to find microstructure characterization in 32760 Super duplex stainless steel after solution treatment at 1080°C followed by using Three different colling media, which is water, oil, and air at room temperature. the following methods will be used to investigate the ferrite-austenite structure and precipitates of secondary phases in stainless steel. The structure is studied under light microscope And SEM EDS. So far, the X-Ray Diffraction analysis has collaborated well with the above- mentioned microstructural investigation. the electrochemical etching are conducted in solutions of 10 % oxalic acid with 2V for 20 second. The experimental results showed character and morphology of these phases very markedly, as do the time for them to form and their effect in different cooling media, the microstructure in untreated specimen consists of (α) ferrite and (γ) austenite, a variations of result with three different cooling media after treatment showed movement of secondary phase and distribution of precipitation along the grain boundary.