Effect of Welding Parameters on Nanostructured Fe-(C, B)-(Cr, Nb) Alloys

New nanostructured Fe-(Nb,Cr)-(C,B) multicomponent alloys have been developed for hardfacing application. They have better wear resistance than traditional Fe-Cr-C alloys. The nano-alpha-Fe, eutectic and hard carboborides phases of the weld metal usually show variations with the welding procedure. 6 test samples with different heat input were welded. It was observed that the percentage of eutectic phase and the distance between carboborides increased for the high heat input. Microhardness of eutectic phases showed a linear relationship with the spacing. Samples with high percentage of alpha-Fe phases showed a severe plastic deformation. Wear resistance was optimal for thinner eutectics phases. The presence of needles carboborides improved wear resistance.

针对堆焊应用场景，本研究研发了新型纳米结构Fe-(Nb,Cr)-(C,B)多组元合金。该合金的耐磨性能优于传统Fe-Cr-C合金。焊缝金属中的纳米α-Fe相、共晶相及硬质碳硼化物（carboboride）相通常会随焊接工艺产生变化。本次实验采用不同热输入量焊接了6个测试试样。观测结果表明，当热输入量较高时，共晶相占比与碳硼化物间距均出现增大。共晶相的显微硬度与该间距呈线性相关关系。α-Fe相占比较高的试样发生了严重的塑性变形。当共晶相厚度较小时，合金耐磨性能达到最优。针状碳硼化物的存在可有效提升合金耐磨性能。