A Comparative Study on Metallographic and Mechanical Properties of Armox 500T Armor Steel Plates Joined Using Different Arc Welding Methods

Abstract

This study comparatively investigated how the metallographic and mechanical properties of Armox 500T armor steel plates joined with Hybrid Plasma Arc Welding (HPAW), Gas Metal Arc Welding (GMAW), and Cold Metal Transfer Arc Welding (CMTW) methods were affected by welding methods. In this context, the Armox 500T welded specimens were examined by radiographic test, optical microscope (OM), Scanning Electron Microscope-Energy distribution spectroscopy (SEM-EDS), hardness, tensile, bending and notched impact tests. OM and SEM microscopy investigations showed that while sufficient fusion occurred between the weld metal and the substrate material in HPAW and GMAW methods. It was determined that the microstructures of the specimens welded with HPAW and GMAW were mostly composed of bainitic structure, in addition to a small amount of martensitic structure while, the microstructure of CMTW welded specimen consist of austenitic, martensitic and partially δ-ferrite structure. Choosing a carbide-forming wire, it was ensured that the hardness values of the weld metal and heat affected zone (HAZ) regions of the specimens combined with all three welding methods were higher than the base metal. The highest tensile strength was obtained in the HPAW welded specimen, while the highest impact notch strength was obtained in the CMTW welded specimen. All of the welded specimens failed within the HAZ and the fracture type is similar to the intergranular fracture type. The mechanical properties results of the specimens combined with three different welding methods have shown that HPAW is the most suitable welding method for joining Armox 500T armor steel.