Abstract: High boron hardfacing alloys reinforced with primary M₂B phases on Q235 steel plates were prepared by the method of flux-cored wire submerged arc welding. The microstructure and boride morphology were investigated using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of WC/W₂C on the microstructure was discussed. It indicated that the volume fraction of primary M₂B phases has increased due to good nucleated cores of incompletely molten W₂C particles provided by casting tungsten carbide or decarburizing reaction of WC powders. Abrasion resistance was evaluated by wet sand rubber wear tests and the wear mechanism was studied using SEM. It shows that primary M₂B grains play a key role in improving abrasion resistance.

Key words: primary M2B phases, Abrasion resistance, Microstructure, Submerged arc welding