Fe-15Cr-3.5B-xC堆焊合金微观组织与耐磨性的研究

Microstructure and wear resistance of Fe-15Cr-3.5B-xC hardfacing alloys

采用CO_2气体保护堆焊的方法,制备了不同碳元素含量的Fe-15Cr-3.5B-xC(x=0.1,0.5,1.0)铁基堆焊合金。采用光学显微镜、XRD,SEM等方法分析了堆焊合金的微观组织结构,并对堆焊合金的宏观硬度和耐磨粒磨损性能进行了测试。结果表明:堆焊合金组织主要由M_2B,Fe_2B,M_(23)(B,C)6,M_3(B,C)和含有铁素体,奥氏体,FeCr固溶体的基体组成。随着碳含量的增加,板条状M_2B型硼化物体积分数逐渐减小。堆焊合金的宏观硬度呈上升趋势,但是耐磨粒磨损性能呈下降趋势。磨粒磨损机制为塑性变形引起的犁沟,硬质相的断裂和脱落。

Fe-15Cr-3.5B-xC(x = 0.1,0.5,1.0wt.%) hardfacing alloys with different carbon contents were deposited by flux-cored wire using metal active gas arc welding(MAG).The effects of carbon contents on microstructure of the hardfacing alloy were analyzed by optical microscope,X-ray diffraction(XRD) and scanning electron microscopy(SEM).The macro hardness and wear resistance of hardfacing alloys were tested.The results indicate that Fe-15Cr-3.5B-xC hardfacing alloys consisted of M_2B,Fe_2B,M_(23)(B,C)_6,M_3(B,C) and matrix,which contained ferrite,austenite and Fe-Cr solid solutions.With the increasing carbon content,the volume fraction of plate strip M_2B decreases.Although the hardness of hardfacing alloys is improved,but wear resistance decreases.The main wear mechanism referred to furrows which caused by plastic deformation,brittle fracture and fall off of hard phase.