不同砂粒粒径多相流中CrMnB堆焊层的损伤行为

CrMnB堆焊涂层的抗空蚀和冲刷磨损能力明显优于传统水轮机用材0Cr13Ni5Mo,但目前对在冲蚀和空蚀共同作用下环境参数对其损伤机制影响的研究还很少.利用旋转圆盘仪,通过对CrMnB堆焊涂层在含砂水中冲刷磨损、冲刷磨损与空蚀共同作用的研究,探索了不同砂粒粒径下涂层的损伤规律和机制.研究表明,粒径的变化引起了材料损伤机制的变化;失重-粒径曲线在一定的粒径范围内有明显的转折区,小粒径和大粒径下材料的损伤形貌差别明显,大粒径时材料的损伤受空蚀影响很大,小粒径时受空蚀影响较小;在冲刷磨损作用下,小粒径时为点坑形的冲蚀破坏机制,大粒径时为犁削破坏机制;在冲刷磨损和空蚀与冲刷磨损共同作用下,小粒径时仍为点坑形的冲蚀破坏机制,大粒径时则为犁削叠加铲削破坏机制.

Damage Behavior of CrMnB Coating in Slurry of Different Particle Size

Cavitation erosion and erosion resistance of CrMnB coating was obviously better than 0Crl3NiSMo used as traditional hydraulic turbine material,but its damage process under the combination effect of erosion and cavitation was hardly investigated. The damage mechanism of CrMnB coating in slurry of different particle size was studied using a rotating disk system.The results indicate that particle size variety results in the change of damage mechanism.There is a clear transition region among a certain particle size in the curve of mass loss vs.particle size.The SEM images of specimens under the condition of big particle size are much different from that under small particle size. Cavitation erosion is important damage way for big particle size but little effect for small particle size.The damage mechanisms under small particle size and big particle size were pitting-type erosion and plowing-shoveling process, respectively.