Mo对高硬度明弧堆焊合金显微组织及耐磨性的影响  

Effects of Mo on microstructure and abrasion resistance of open arc hardfaced alloys with high hardness

作　　者：龚建勋[1] 刘江晴 李毅[1] 

机构地区：[1]湘潭大学机械工程学院,湖南湘潭411105

出　　处：《金属热处理》2016年第5期67-72,共6页Heat Treatment of Metals

基　　金：湖南省自然科学湘潭联合基金(2015JJ5031)

摘　　要：采用药芯焊丝自保护明弧焊方法制备了含有11%~13%Cr、3.5%~3.8%C、2.1%~2.3%Nb、0.6%~0.7%B、0%~4.0%Mo（质量分数）且宏观硬度高达65 HRC的耐磨合金。采用光学显微镜、X射线衍射仪和扫描电镜,研究了钼含量对其显微组织及耐磨性的影响。结果表明：随着钼含量增加,合金组织整体细化,形成了强韧性配合良好的奥氏体＋针状马氏体复合基体以及韧性更好的M（23）（C,B）6＋原位析出Nb C耐磨相,脆性变态莱氏体Ld＇的形成得到明显抑制。此外,湿砂磨粒磨损试验结果表明,适量Mo减小碳化物间隔尺寸及Nb C颗粒脱落几率,显著改善耐磨性,但如加入过多,合金磨损机制会变为磨粒显微切削。Wear-resisting alloys containing 11%-13% Cr, 3.5%-3.8% C, 2.1%-2.3% Nb, 0.6%-0.7% B and 0%-4.0% Mo （mass fraction） with 65 HRC hardness were prepared by the method of flux-cored wire open arc welding. The effects of molybdenum on the microstructure and the abrasion resistance were investigated by optical microscope （OM）, X-ray diffractometer （XRD） and scanning electron microscopy （SEM）. The results show that with higher molybdenum, the microstructure is full refined and consists of composite matrix with austenite and acicular martensite and the wear-resisting phases composed of M23 （ C, B） 6 and in-situ precipitated NbC particles, and the formation of brittle abnormal ledeburite is markedly suppressed. In addition, the results of wet sand wear test show that the abrasion resistance of the open arc hardfaced alloys is significantly improved with proper molybdenum content due to reducing the carbide spacing and decreasing the peeling rate of NbC particles. But the excessive molybdenum content can lead to the wear mechanism of the alloy becomes of micro-cutting.

关 键 词：明弧 堆焊 显微组织 耐磨性 药芯焊丝 

分 类 号：TG422.1[金属学及工艺—焊接]