本文基于现用连铸辊414N硬面层，设计了Nb/Ti/V微合金化的MA414N焊丝，并用于硬面层堆焊，研制了一种微合金硬面层。通过高温磨损试验对比了414N与MA414N的高温耐磨性，结果表明，500 ℃~700 ℃，MA414N的磨损量均低于同温度下的414N，在700 ℃时仅为414N的22%，高温耐磨性较414N显著提高；414N硬面层主要产生氧化磨损、磨粒磨损与疲劳磨损，磨损程度随温度升高而增大；MA414N硬面层主要产生氧化磨损，伴随少量磨粒磨损与疲劳磨损，磨损程度随温度升高而减小。结合SEM/EDX、TEM、XRD分析得出，MA414N在高温环境下析出弥散的纳米(Nb, Ti, V)(C, N)，产生高温自增强效应，高温耐磨性得以显著提高；其次，微合金化抑制了沿晶(Cr, Fe)23C6的析出，降低了沿晶裂纹萌生与沿晶碳化物剥落的风险，促进磨损面形成更加致密的六方(Fe, Cr)2O3，起到更好的保护作用；此外，微合金化还降低了MA414N中软韧相奥氏体的含量，在提高高温耐磨性方面具有一定贡献。根据研究结果，最终提出了414N和MA414N硬面层高温磨损机制模型。

Based on 414N hard-faced layer, the microalloyed MA414N wire with niobium (Nb), titanium (Ti), and vanadium (V) was designed and used as novel hard-faced layer by build-up welding in this work. High-temperature wear experiments were conducted to compare the wear resistances of 414N and MA414N. It was found that the wear volume of MA414N was remarkable lower than that of 414N at the temperature range of 500 °C to 700 °C. Above all, the wear volume of MA414N is only 22% of the 414N at 700 ℃, clearly showing a significant improvement in high-temperature wear resistance. The high-temperature wear methods are oxidation wear, abrasive wear, and fatigue wear for the 414N hard-faced layer, and its wear rate increased with elevating temperature. However, it was found that the major method is oxidation wear for the MA414N, with a small number of abrasive wear and fatigue wear, and the wear rate decreased with elevating temperature. Based on SEM/EDX, TEM, and XRD analyses, it was concluded that the dispersively precipitated nanosized (Nb, Ti, V)(C, N) particles introduced a self-strengthening effect in MA414N during high-temperature wear process, leading to a significantly improved wear resistance. Secondly, microalloying inhibited the precipitation of intergranular (Cr, Fe)23C6, which not only reduced the risk of intergranular crack initiation and carbide spalling, but also promoted the formation of dense hexagonal (Fe, Cr)?O? on wear surface with strong protection. Furthermore, microalloying reduced the content of austenite in MA414N during wear process, which also had certain benefits to the improvement of high-temperature wear resistance. According to the above-mentioned results, two models were put forward to explain the high-temperature wear mechanism of 414N and MA414N, respectively.