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研制了不同La2O3加入量的高碳钢堆焊用药芯焊丝,并制作了相应的堆焊试样。采用金相显微镜对其显微组织进行了观察,X射线衍射仪对其相组成进行了分析,洛氏硬度计和砂带式摩擦磨损试验机对其宏观硬度和耐磨性进行了检测,场发射扫描电子显微镜对其磨损表面进行了观察。结果表明:堆焊金属的组织主要由黑色针状马氏体、白色网状高合金马氏体及残余奥氏体组成。随着La2O3加入量的增加,高合金马氏体含量增加,堆焊金属的硬度和耐磨性也增加,当La2O3加入量为3.44%(质量分数)时,二者均达到最大值。堆焊金属中加入La2O3使初生奥氏体晶粒细化,提高了其基体组织的强硬性,与作为耐磨相的高合金马氏体共同作用,使堆焊金属的耐磨性提高。
A new flux-cored welding wire for high carbon steel surfacing with different amount of La2O3 was developed and the corresponding surfacing samples were made. The microstructure was observed by optical microscope. The phase composition was analyzed by X-ray diffractometer. The macroscopic hardness and wear resistance were measured by Rockwell hardness tester and belt-type friction and wear tester. Emission scanning electron microscopy of its wear surface was observed. The results show that the surfacing metal mainly consists of black acicular martensite, white reticulated martensite and retained austenite. With the increase of the amount of La2O3, the content of high-martensite increases and the hardness and wear resistance of the deposited metal increase. When the amount of La2O3 added is 3.44% (mass fraction), both reach the maximum. The addition of La2O3 in the surfacing metal makes the primary austenite grain refinement and enhances the toughness of its matrix structure, which in combination with the high-alloy martensite as the wear-resistant phase improves the wear resistance of the deposited metal.