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针对球铁的汽蚀特性进行了研究,认为球铁中的石墨是球铁的汽蚀破坏源。汽蚀过程为:汽蚀冲击力首先击碎汽蚀面上的石墨并留下坑点和孔洞;孔洞底部基体组织发生变形以及汽蚀面下出现脱体现象;基体组织萌生裂纹;汽蚀裂纹扩展汇交形成层状剥蚀。球铁比普通灰铁具有较优的抗汽蚀性的主要原因,是由两种铸铁不同的石墨形状和结晶过程引起的。回火马氏体球铁具有最优的抗汽蚀性,脱体现象仅发生在1～2个共晶团的间距内,裂纹扩展受马氏体片的掉列方向影响;铁素体球铁具有最差的抗汽蚀性,在铁素体环中裂纹容易形成和扩展。提高球铁抗汽蚀能力的方法就是要消除铁素体环。
The cavitation characteristic of ductile iron was studied, and it is concluded that the graphite in ductile iron is the cavitation damage source of ductile iron. The cavitation process is as follows: the cavitation impact force firstly breaks down the graphite on the cavitation surface and leaves pits and holes; the matrix structure at the bottom of the hole is deformed and the phenomenon of detachment occurs under the cavitation surface; matrix tissue initiation crack; cavitation crack Extend the intersection to form layered erosion. The main reason that ductile iron has better resistance to cavitation than ordinary gray iron is caused by the different graphite shapes and crystallization processes of the two cast irons. Tempering martensitic ductile iron with the best anti-cavitation, off phenomenon occurs only in 1 ~ 2 eutectic spacing, the crack growth by the martensite film out of the direction of influence; ferrite ball Iron possesses the worst resistance to cavitation and cracks are easily formed and expanded in ferrite rings. The way to improve the cavitation resistance of ductile iron is to eliminate ferrite rings.