Microhardness and Microstructure of Fiber Laser Welded S960 and S700 Steels

Year 2019, Volume: 3 Issue: 1, 15 - 21, 26.08.2019

Zülküf Balalan Ömer Ekinci

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

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