ESSC & DUPLEX 2019

Performance of stainless steels (SS) is a direct function of the microstructure, and phase quantification is an important experimental procedure for microstructural characterization. X-ray diffratometry (XRD) is widely used in phase identification of SS, and analysis of the diffracted intensity peaks of the phases allows the determination of their volume fractions. X-ray diffraction patterns using as X-ray sources of copper or chromium targets were obtained from two different SS. The first group of samples are composed of a duplex stainless steel (DSS) solution-treated at three different temperatures, in order to obtain different ferrite-to-austenite volume fraction ratios. The other group was composed by quenched and tempered samples of a supermartensitic stainless steel (SMSS) with different amounts of retained and/or reversed austenite. It was found that copper source of X-rays results in better quantification of phases for both SS studied. However, the technique was influenced by crystallographic texture in DSS phases quantification; in the absence of marked texture, XRD results in quantification similar to other techniques. Only SMSS samples with higher amounts of coarse reversed austenite (in this case, samples tempered for 2 h at 625 or 650 °C) could have austenite partially quantified, being magnetic measurements a better indirect technique for quantification of phases in SMSS.