摘要
工程专用自卸车钢板弹簧工况恶劣,经常发生断裂和磨损等失效,更换频繁增加用户使用成本。针对这一现状,在50CrVA板簧钢常规回火工艺前进行深冷处理。对不同处理工艺的冲击试件设计了正交试验方案,采用极差分析获得较优工艺组,再从中选出3组进行洛氏硬度检测。对冲击试件断口进行观测,分析其断裂机理,并采用扫描电镜观察其显微组织。结果表明:在保证50CrVA板簧钢相对于对照(未深冷)组硬度不降低的前提下,试验方案优化的工艺组,即深冷温度-196℃、保冷时间24 h、深冷次数3次,其冲击韧度值比对照组提升了1.86 J·cm-2,硬度比对照组硬度提升了0.16 HRC。冲击断裂为韧窝断裂机制,属于延性断裂。深冷处理受深冷温度、降温速率、保冷时间和深冷次数的影响,试样不同程度析出细长针状下贝氏体和板条状马氏体。
The plate spring of special dump truck is in bad working condition,such as fracture and wear often occur,and the frequent replacement increases the cost of user.In view of this situation,the cryogenic treatment process test was carried out for 50 CrVA plate spring steel.The orthogonal test scheme was designed for impact specimens with different treatment processes,and the optimal process group was obtained by extreme difference analysis,then three groups were selected for Rockwell hardness test.The fracture surface of the impact specimen was observed,the fracture mechanism was analyzed,and the microstructure was observed by scanning electron microscope.The results show that under the condition that the hardness of 50 CrVA spring steel does not decrease compared with the control group without cryogenic treatment,the process group optimized by the test scheme is cryogenic temperature of-196℃,cooling time of 24 h and cryogenic time of 3 times.The impact toughness is 1.86 J·cm-2 higher than that of the control group,and the hardness is 0.16 HRC higher than that of the control group.The impact fracture is dimpled fracture mechanism and belongs to ductile fracture.Under the influence of cryogenic temperature,cooling rate,cooling time and cryogenic times,slender needle-like lower bainite and lath-like martensite are precipitated in different degrees.
作者
高源
陈峙
闫献国
成俊秀
GAO Yuan;CHEN Zhi;YAN Xian'guo;CHENG Junxiu(School of Mechanical Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China)
出处
《热加工工艺》
北大核心
2019年第24期119-122,共4页
Hot Working Technology
基金
山西省自然基金面上青年项目(201701D221134)
太原科技大学博士启动金资助项目(20162026).
关键词
50CrVA板簧钢
深冷处理
正交试验
冲击韧性
洛氏硬度
50CrVA plate spring steel
cryogenic treatment
orthogonal test
impact toughness
Rockwell hardness
