服役过程中连续挤压模具表层显微组织演变与开裂  

MICROSTRUCTURE EVOLUTION AND CRACKING ANALYSIS ON THE SURFACE LAYER OF THE CONTINUOUS EXTRUSION DIE DURING THE SERVICE PROCESS

作　　者：聂斌英[1] 

机构地区：[1]宜春学院化学与生物工程学院,宜春336000

出　　处：《机械强度》2017年第6期1343-1347,共5页Journal of Mechanical Strength

摘　　要：铜及其合金型材H13钢连续挤压轮模具常发生早期剥落失效。通过对挤压轮服役不同时间段后的显微组织观察发现:服役初期挤压轮槽表层的马氏体组织逐渐回火分解、硬度下降;随着服役时间的增加,挤压轮槽表层马氏体分解加剧、大量碳化物弥散析出,并在次表层萌生热疲劳显微裂纹;继续增加服役时间,挤压轮表层马氏体分解殆尽、碳化物严重粗化,显微裂纹向表面露头,并在熔融态铜的挤压作用下显微裂纹逐渐向基体内扩展,导致挤压轮槽开裂。The earlier failures are always occurred in the H13 steel continuous extrusion-wheel die for section copper and its alloy. The experimental analysis on the microstructures evolution of the extrusion-wheel die after different service times were made,and the tests showed that the martensite resolved into tempered martensite and the hardness reduced gradually in the surface layer of the groove of continuous extrusion-wheel die in the early stage service. As service time delayed,the martensite resolution accelerated and large quantities carbides precipitated,and the thermal fatigue cracking initiated from the subsurface of the groove. After that the services proceed,the martensite resolved completely and carbides coarsen seriously. The fatigue cracks of the subsurface layer drove towards the surface and propagated into the interior of the groove on the assistance of the melting copper alloy,which resulted in failure of the groove of the continuous extrusion-wheel die.

关 键 词：H13钢 铜及铜合金型材 挤压轮 显微组织演变 

分 类 号：TG142[一般工业技术—材料科学与工程]