Chiang Mai Journal of Science

     The current research studied two samples of rail steel grade 900A deposited with different electrodes, namely, electrodes A and B, using the Shielded Metal Arc Welding (SMAW) process. This research fi nds out the suitable hardness values of the various electrodes. The phase identifi cation and microstructural analysis of weld metal were conducted using X-ray diffraction (XRD) and an optical microscope, respectively. The micro-hardness profi les along the cross-section of the weldment were acquired using a micro-Vickers hardness tester, and a Brinell hardness tester measured the hardness values on the top surface of the weld metal. According to the results, the diffraction angles of the XRD patterns for all weld metal samples differed due to their distinct microstructures. The microstructure of the weld metal, in particular, produced the primary infl uence on the hardness.