(中南大學(xué) 機(jī)電工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 利用掃描電鏡與金相觀察等分析方法，研究了碳化鈦-高錳鋼結(jié)硬質(zhì)合金在焊接和使用過(guò)程中產(chǎn)生裂紋與碎片的成因。結(jié)果表明， 當(dāng)硬質(zhì)相(TiC)之間的粘結(jié)相成分Mn, Fe等元素含量偏低時(shí)，則粘結(jié)相的相對(duì)含量明顯減少，粘結(jié)效果變差，致使硬質(zhì)相在燒結(jié)過(guò)程中發(fā)生鄰接和聚集長(zhǎng)大，晶粒出現(xiàn)不均勻粗化，導(dǎo)致合金微區(qū)強(qiáng)韌性降低，在焊接應(yīng)力(或外力)作用下容易產(chǎn)生微裂紋，若應(yīng)力(或外力)進(jìn)一步增大或作用時(shí)間延長(zhǎng)，微裂紋將迅速擴(kuò)展形成宏觀裂紋進(jìn)而脆裂成碎片。提出了在燒結(jié)過(guò)程中避免粘結(jié)相揮發(fā)、流失及硬質(zhì)相鄰接長(zhǎng)大的工藝措施，以改善合金的組織與性能，防止產(chǎn)生裂紋與碎片。
關(guān)鍵字: 碳化鈦；高錳鋼結(jié)硬質(zhì)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，F(xiàn)e 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
