Abstract:
Welded surfacing layers containing internally produced superhard TiC and VC particulates were prepared on Q235-A alloy making use of the high temperature arc metallurgic reaction among Fe-Ti, Fe-V, graphite, and rutile, etc. The abrasive wear-resistance of the resulting welded surfacing layers was evaluated on an MLD-10 friction and wear tester, using the surfacing layer made from EDZCr-C-15 welding rod as a reference. The phase compositions and microstructures and worn surface morphology of the welded surfacing layers were analyzed by means of X-ray diffraction and scanning electron microscopy, while the macrohardness and microhardness were comparatively investigated as well. As the results, the surfacing layers containing dispersively distributed carbides particulates had much better abrasive wear-resistance than the one made from the EDZCr-C-15 welding rod, though they had a little bit larger hardness than the latter. The greatly increased wear-resistance of the welded surfacing layers containing the superhard carbides particulates was thus attributed to their special phase compositions and microstructures. Namely, the target welded surfacing layers were composed of lath martensite as the matrix which was capable of well bonding and supporting the dispersed carbides particulates and decreasing the abrasion energy by way of plastic deforming. In other words, the supaerhard carbides particulates and the soft lath martensite matric had well balanced hardness and toughness, which contributed to greatly increase the wear-resistance of the welded surfacing layers containing the superhard carbides particulates.