Abstract
The railway maintenance industry has been using welding process to repair the damage on the rail head surface due to its constant and continuous friction with train wheels. Hardfacing is one of the adaptable methods that can build up the hard and wear resistant surface layer on the surface of substrate material. In this work, the UIC-54 rail head surface was grinded and welded with three layers by using HF-350 flux-cored wire with 90% argon, 10% CO2 shielding gas under 245A current and 23 V voltage. The deposit specimen and it surrounds have been examined to determine its structure and mechanical properties. Results show that the base microstructure consists of broad ferrite and pearlite structures while for weld area with acicular ferrite structures. Hardness result show improved hardness properties for base to weld metal from 381 to 437 HV. The tensile results show the deposited layer have the highest Ultimate Tensile Strength (UTS), 1162 MPa compared to HAZ and base metal. The fracture mode was assessed by SEM indicates the ductile characterizations that contained micro voids and dimples on fractured surface. The obtained results exhibit superior properties of repaired welded layers, due to the change of microstructure from original pearlite structure in base metal to the acicular ferrite structure in welded layer in relation to mechanical properties results.
Published Version
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