低冲蚀角下40Cr冲蚀与空蚀耦合磨损特性研究
Exploring Characteristics of Coupled Erosion and Cavitation Wear of 40Cr in Low Impact Angle

基于CFD理论,数值模拟了低冲角下(冲蚀角α<40°)冲蚀和空蚀耦合磨损的流场特性,并将数值分析结果与实验结果进行对比,研究了40Cr在低冲角下耦合磨损的失效特性。研究发现:1)耦合磨损的破坏程度随着冲蚀角的增加先增大后减小降,在临界角α=30°时磨损最严重,此时耦合磨损流场的溃灭冲击压强达到了最大的1×107Pa,在这种高强度冲击的反复作用下,材料更容易发生疲劳失效;2)当α<30°时,40Cr材料表面的磨痕主要为微切削犁沟,并有少量的针孔状蚀坑;3)当α>30°时,材料表面的磨痕主要为瞬时高温氧化和疲劳剥落引起的夹杂着白色氧化铁颗粒的蚀坑。40Cr试件失重量随冲蚀角变化趋势与三次样条曲线吻合得很好。
Based on the CFD theory, the flow field characteristics of coupled erosion and cavitation wear were numerically simulated in different impact angles (α<40°), and the simulation results were compared with the experimental results in order to study the failure characteristics of coupled wear of 40Cr in the low impact angle. The simulation results show: 1) the damage extent of the coupled wear increases first and then drops as the impact angle changes, and the collapse impact pressure of coupled wear reaches a maximum of 1×107 Pa when the impact angle is about 30°, the materials are more prone to fatigue failure in this kind of repeated impact; 2) the failure of 40Cr is mainly micro-cutting furrows and some pinhole-like pits when the impact angle α<30°; 3) the honeycomb pits are mixed with white iron oxide particles caused by fatigue spalling and high-temperature oxidation when α>30°. The trend between the weight loss of 40Cr specimen and its impact angle coincides with the cubic spline very well