Microstructure and Mechanical Properties of 3-Wire Electroslag Welded (ESW) High-Speed Pearlitic Rail Steel Joint

Abstract

The present paper aims at utilizing the 3-wire electroslag welding (ESW) to join high-speed pearlitic rail steels where microstructure and mechanical properties were investigated. The welded joint has produced an improved fracture force of 1396KN. WM was consisted of ferrite and pearlite having hardness of 27HRC, tensile strength of 748MPa and toughness of 12J, successively. HAZ was composed of pro-eutectoid ferrite and pearlite, where austenite grain size and pearlite colony size were reduced by moving away from the fusion line. In HAZ, near to the fusion line, the austenite grain size was 143±19μm, pearlite colony size was 52±9μm and pearlite interlamellar spacing was 90±27nm, which has produced hardness of 43.5HRC, tensile strength of 1228MPa, and toughness of 8J, successively. The entire investigation concludes that 3-wire ESW is an optimum and viable method, which has provided fine pearlite microstructure along with improved hardness and tensile strength.