(中南大学 机电工程学院，长沙 410083)
摘 要: 利用扫描电镜与金相观察等分析方法，研究了碳化钛-高锰钢结硬质合金在焊接和使用过程中产生裂纹与碎片的成因。结果表明， 当硬质相(TiC)之间的粘结相成分Mn, Fe等元素含量偏低时，则粘结相的相对含量明显减少，粘结效果变差，致使硬质相在烧结过程中发生邻接和聚集长大，晶粒出现不均匀粗化，导致合金微区强韧性降低，在焊接应力(或外力)作用下容易产生微裂纹，若应力(或外力)进一步增大或作用时间延长，微裂纹将迅速扩展形成宏观裂纹进而脆裂成碎片。提出了在烧结过程中避免粘结相挥发、流失及硬质相邻接长大的工艺措施，以改善合金的组织与性能，防止产生裂纹与碎片。
关键字: 碳化钛；高锰钢结硬质合金；碎裂成因
manganese steel bonded carbides
（School of Mechanical and Electrical Engineering, Central South University University, Changsha 410083, China）
Abstract:The causes for crack formation and splinter occurrence in TiC-high manganese steel bonded carbides were investigated by means of SEM and metallographic analysis. If the content of Mn，Fe in bonding phase between hard phase TiC is low, the relative content of bonded phase between hard phases is obviously decreased, and its cohesiveness is turned to bad, which leads to the overlap and coalescence o f hard phases during sintering process, then inhomogeneous coarse-crystallized grain occurs obviously. Due to low strong toughness, it is easy to crack under welding stress (or external force). If the stress (or external force) is in creased or the action period is prolonged, microcracks are propagated promptly to big cracks, eventually change to splinters. Technological measures for improving structure and performance of the alloys to prevent cracking and splintering were proposed.
Key words: TiC; high manganese steel bonded carbide; causes of cracking
