Microstructure Characterization and Mechanical Properties of 9Cr-1.2W Weld Metal
Fikret KABAKCI Mustafa ACARER Selcuk KESKINKILIC Filiz KUMDALI ACAR İsmail Hakkı Kara
AbstractHigh CrMo (W) steel is widely used in ultra-super critical (USC) power plant applications operation temperature up to 620 oC. The steels and their weld metal are used for tempered condition. Tempering temperature must be below Ac1 temperature of the weld metal. Welding of the steel is generally applied by shielded metal arc welding (SMAW) with multi-pass process. In this study, stick electrodes were fabricated for high chromium tungsten steel in Gedik Welding Company. Microstructure and mechanical properties of the all weld metal produced by the stick electrodes were investigated following tempering at 760 oC for 4h. Microstructure was characterized by optical microscope (OM) and scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS). Differential scanning calorimetry (DSC) analyze was used to determine transformation temperature of the weld metal. Hardness measurement, tensile test and charpy impact test were carried out. Fracture surfaces of the samples were also investigated via SEM.