喷射成形含铌M3型高速钢的组织和耐磨性  

Microstructure and wear resistance of spray-formed M3 high speed steel with niobium addition

作　　者：王和斌[1] 侯陇刚[1] 卢林[1] 张金祥[1] 崔华[2] 黄进峰[1] 张济山[1] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《工程科学学报》2015年第3期329-335,共7页Chinese Journal of Engineering

基　　金：国家重点基础研究发展计划资助项目(2011CB606303)

摘　　要：采用喷射成形技术制备了M3型高速钢和以Nb替代V的M3型高速钢.利用扫描电镜、X射线衍射、差示扫描量热仪和金相显微镜研究了Nb对M3型高速钢组织的影响.喷射成形能有效消除宏观偏析,细化组织.以Nb代V,提高了MC型碳化物开始析出温度,大量MC相先于共晶反应析出,呈独立的近球形分布于晶界,同时其尺寸减小.由于消耗大量C,抑制了共晶反应,M2C片层数量减少且厚度变薄,其在热变形过程中更易于分解,进一步增加了组织均匀性.低温低载荷时含铌的M3型高速钢抗磨损性能显著优于M3高速钢,温度升高到500℃时磨损机制逐渐以氧化磨损为主,两合金的抗磨损性能差距减小,主要原因是大量呈弥散球形分布的含铌MC型碳化物能有效提高高速钢的磨粒磨损抗性,而其对抗氧化性能并无明显作用.M3 high speed steel （HSS） with or without niobium addition was prepared by spray forming, and the effect of niobium on the microstructure of M3 HSS was investigated by scanning electron microscopy （SEM） combined with energy dispersive X-ray （EDX） spectroscopy, X-ray diffraction （XRD） analysis, differential scanning calorimetry （DSC） and optical microscopy （OM）. Fi- ner and uniformly-distributed grains without maerosegregation appear in the as-deposited HSS, and the addition of niobium tends to shift the precipitation of primary MC-type carbides to a higher temperature. Plenty of refined niobium-containing MC carbides precipi- tate as isolated sphere particles in the grain boundaries before onset of eutectic reaction. Niobium mainly appears in primary MC-type carbides by consuming carbon, which suppresses the degree of eutectic reaction to a large extent, leading to the decrease in both amount and size of ME C lamella carbides. The refined metastable ME C carbides in Nb-containing HSS can be completely decomposed easily during hot deformation, and the homogeneity of carbides in Nb-containing HSS is improved. The wear-resistant property of Nb- containing HSS is superior to that of M3 HSS at a lower load or temperature. But this gap is reduced with temperature rise. The main reason is that the large number of refined primary MC carbides can improve the abrasive wear resistance of HSS, but have no effect on its oxidation resistance.

关 键 词：高速钢 喷射成形 铌 显微组织 磨损抗性 

分 类 号：TG142.45[一般工业技术—材料科学与工程]