采用复合粉体颗粒+H08A实心焊丝的自保护明弧焊法在Q235A钢表面制备了Fe-Cr-V-B-C系高硼堆焊合金,研究了钒质量分数(0~7.5%)对合金显微组织及耐磨性能的影响。结果表明:当钒质量分数为0时,堆焊合金由α-Fe、M₂B和M₃C等相组成;当钒质量分数为1.5%,块状M₂B相的含量和尺寸增大,其晶间析出点状、十字花状VC相;当钒质量分数增至3.0%和4.5%时,初生M₂B晶粒细化;当钒质量分数增至6.0%时,M₂B相晶间和晶内析出针状和条状V₃B₂相;当钒质量分数增至7.5%时,V₃B₂相明显增多,M₂B相减少。随着钒含量的增加,堆焊合金的硬度先升后降,磨损质量损失先降后升,当钒质量分数3.0%时,硬度最高,为61.6 HRC,磨损质量损失最小,为0.019 4 g,堆焊合金耐磨性能最佳。

Fe-Cr-V-B-C system high boron hardfacing alloys were prepared on Q235A steel surface by self-shielded open arc welding with composite powder particles and H08A solid wire. The effects of vanadium mass fraction (0-7.5%) on the microstructure and wear resistance were studied. The results show that when the mass fraction of vanadium was 0, the hardfacing alloy consisted of α-Fe, M₂B and M₃C phases. When the vanadium mass fraction was 1.5%, the content and size of the bulk M₂B phase increased, and point and cross flower-like VC phase was precipitated between grains. When the vanadium mass fraction increased to 3.0% and 4.5%, the primary M₂B grains were refined. When the vanadium mass fraction increased to 6.0%, needle and strip V₃B₂ phase was precipitated between and within M₂B phases. When the vanadium mass fraction increased to 7.5%, the V₃B₂ phase content increased significantly and the M₂B phase content decreased. With the increase of vanadium content, the hardness of the hardfacing alloy first increased and then decreased, and the wear mass loss first decreased and then increased. When the vanadium mass fraction was 3.0%, the hardfacing alloy had the highest hardness of 61.6 HRC and the smallest wear mass loss of 0.019 4 g, indicating the hardfacing alloy had the best wear resistance.