Microhardness and Microstructure of Fiber Laser Welded S960 and S700 Steels

Authors : Zülküf Balalan, Ömer Ekinci

Pages : 15-21

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Publication Date : 2019-08-26

Article Type : Research

Abstract :In this study, keyhole laser bead on plate welding of 6 mm thick high strength low alloy (HSLA) of S960 steels and keyhole laser butt welding of 13 mm thick (HSLA) of S700 steels were performed by using 16 kW fiber laser. For different welding parameters of S960 and S700 steels, microhardness and microstructure on the fusion zone, heat affected zone and base material were determined. Furthermore, X-Ray Diffraction (XRD) patterns of the welded zone was revealed. In laser bead on plate welding joints of S960 steels, microhardness of fusion zone (FZ) is approximately 60 HV higher than base material for all the welding specimens while in laser butt welded joints of S700 steel, microhardness of FZ is approximately 30 HV. On the other hand, microstructures of FZ consists of martensite phases, whereas both base material S960 and S700 consist of tempered martensite and strip-like martensite.
Keywords : laser welding, microhardness, microstructure, S960