【摘要】 采用药芯焊丝埋弧堆焊方法制备含有C0.5%～0.7%,Cr9%～12%,B0%～2.25%(质量分数)的堆焊合金。借助光学显微镜、扫描电镜、X射线衍射和微区EDS分析等手段研究其显微组织及分布形貌。结果表明,其显微组织由铁素体+奥氏体+马氏体+硼化物((Fe,Cr)2B,(Fe,Cr)23(C,B)6,(Fe,Cr)B和(Fe,Cr)3(B,C))等组成,硼化物呈条状、菊花状、块状甚至蜂窝状等形态,不同硼化物数量及其分布形态随硼含量而改变,其中最为典型是(Fe,Cr)23(C,B)6呈菊花状并聚集分布。另外,考察了硼含量对Fe-10Cr-xB-0.6C堆焊合金硬度及耐磨性的影响,耐磨粒磨损试验结果表明,高硼堆焊合金的磨损性优良,当聚集分布的硼化物数量过多,磨粒压入基体及其显微切削运动受到硼化物的有效阻碍,但部分硼化物脱落留下的空洞使其压入切削变易,这使得硼化物与基体的界面结合强度成为影响其耐磨性的一个重要甚至主导因素。更多还原

【Abstract】 Hardfacing alloys containing 0.5%-0.7%C, 9%-12%Cr, 0%-2.25%B （mass fraction） were deposited on Q235 steel by flux-cored wire submerged arc welding （SAW）. Microstructure of the hardfacing alloys was investigated by means of optical microscopy （OM）, scanning electron microscopy （SEM）,X-ray diffraction （XRD） and energy dispersive spectrometer （EDS）. The microstructure of the alloys consists of ferrite, austenite and martensite, borides of （Fe,Cr）₂B, （Fe, Cr） 23 （C, B）₆, （Fe, Cr）B and （Fe, Cr）₃（B, C）. The borides with strip, rosette, blocky and honeycomb shape are observed in the alloys and the volume fraction and morphology of the different boride depends on boron content. Among them, the typical shape of （Fe, Cr） 23 （C, B）₆ is rosette, and aggregationally distributed. In addition, the effects of boron content on hardness and wear properties of the hardfacing alloys were examined and abrasion experimental result demonstrates that abrasion resistance of Fe-10Cr-xB-0.6C hardfacing alloy is excellent. When volume fraction of the aggregationally distributed borides is too high, although the plunging and subsequent micro-cutting movement of abrasive particle can be effectively blocked, cavities left by some released borides from matrix make it easy, so bond strength between boride and matrix becomes an important or even main factor for abrasion resistance of the alloys.更多还原