Effects of titanium additive on microstructure and wear performance of iron-based slag-free self-shielded flux-cored wire

In this investigation, a new slag-free type of iron-based self-shielded flux-cored wires (SSFCW) with varying titanium content was developed to fabricate experimental hardfacing alloys. The titanium can be transferred to the weld pool using magaluma powder and graphite in the wire as stronger deoxidizers. The phase composition and microstructure of the as-prepared alloys were characterized by X-ray diffraction and scanning electron microscopy. The wear behavior of SSFCW was investigated using a HT-500 pin-on-disk tribometer. The results showed that TiC was preferentially formed in the alloy. It acted as the nucleus of the primary M7(C,B)3 (M = Cr, Fe mainly) carbides; and that it decreased the amount of M7(C,B)3 when titanium was added into the wires. When 24 wt.% ferrotitanium (Fe–Ti: containing 30 wt.% Ti) was added, the microstructure of the alloy changed from a hypereutectic structure to a hypoeutectic one due to the formation of TiC, which consumed carbon. The addition of titanium to iron-based SSFCW improves the wear resistance of the alloy with respect to the higher hardness and refined microstructure. The wear loss of the sample with 24 wt.% Fe–Ti was the smallest among all the samples.