硅对自保护明弧堆焊合金Fe-Cr-C-B显微组织及性能的影响

Effect of Si on microstructure and properties of Fe-Cr-C-B self-shielded open arc hardfacing alloys

采用药芯焊丝自保护明弧焊方法在Q235A基体上制备了Fe-Cr-C-B-Si耐磨合金.借助光学显微镜、扫描电镜、X-射线衍射仪和硬度测试等手段研究了以Fe-Si形式加入的硅含量对其组织和性能的影响.结果表明,硅含量显著影响其碳化物形貌、分布及尺寸,具体表现为硅含量提高,随之出现了硬度高达9.75～13.54 GPa的白色团状相,尺寸增大并呈聚集分布;背散射电子扫描图、电子能谱分析和显微硬度测试显示该团状相为双相复合碳化物,其内部为M23C6相,外表则是较低Cr,C元素含量的碳化物.此外湿砂磨粒磨损试验结果表明,适量硅显著改善了明弧堆焊合金的耐磨性,所含M23C6相尺寸和显微硬度明显影响其磨损失重.

Fe-Cr-C-B-Si wear-resistant alloy was deposited on Q235 base metal by flux-cored wire self-shielded open arc welding.With the addition of ferrosilicon powders,the effect of silicon content on the microstructure and the properties of hardfacing alloys were researched by optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD) and hardness measurement.The results show that silicon content has a significant effect on the morphology,the distribution and the size of the carbides.With higher silicon content,it appears the white nodular phases with 9.75-13.54 GPa in hardness,which becomes bigger in size and is congregating distributed.The analyses results by back-scattered scanning electron images as well as energy dispersive spectrometer(EDS) and microhardness shows that these nodular phase grains are two-phase complex carbide,in which the inner M23C6 are enclosed by the carbide with lower chromium and carbon content.Furthermore,the results of wet sand rubber wear tests indicate that proper silicon content significantly improves the abrasion resistance of hardfacing alloys.The size and the microhardness of the contained M23C6 phases have a direct effect on wear mass loss.