摘要
通过断口形貌观察、金相检验和硬度检测等试验,确定了轴的断裂性质及断裂原因。结果表明:从动轴的断裂形式是中心为一次性的过载断裂,边缘为疲劳断裂,疲劳源区在次表层。从动轴的断裂原因是由于轴中心存在原始缺陷,在使用中扩展为一条长约140 mm的大裂纹,裂纹源从大裂纹的边缘沿横向扩展,断口形貌复杂,断裂形式多样;从动轴材料心部组织为铁素体+珠光体,有魏氏组织倾向,按YB31-64标准评级为C列1级,晶粒大小不均匀,有混晶现象。从动轴表面热处理工艺控制不当,使得表面硬度不高,未达到调质处理的组织。
The feature and cause reason of double-circular-arc gear reducer shaft were analyzed by micro-macro observation on the fracture surface, metallographic examination and hardness testing. The results show that the fracture mode of the shaft is one-off overload fatigue of the center and fatigue fracture of the margin. The fatigue source area is in the sub-surface. The fracture reason is due to the original defects existing in the shaft center. It is expanded to a total of 140 mm big crack in use. As the crack source is extended laterally along the big crack edge, the fracture morphology and fracture forms becomes complicated. The driven shaft heart material is made of ferrite and pearlite, appearing widmanstatten tendency. According to YB31-64 standard, the rating is C column 1 level and the grain size is uneven, with the mixed crystal phenomenon. In addition, the driven shaft surface heat treatment process controls improperly, the surface hardness is not high to reach the quenching and tempering treatment.
出处
《热加工工艺》
CSCD
北大核心
2013年第18期192-195,共4页
Hot Working Technology
基金
江苏省科技支撑计划项目(BE20120044)
徐州市战略新兴产业发展专项基金项目(XX12A016)
徐州市科技型中小企业创新基金项目(XC12A001)
关键词
轴
疲劳断裂
混晶
热处理
shaft
fatigue fracture
mixed grain
heat treatment
