28Cr铸铁冲蚀磨损过程中碳化物及基体的作用机理

利用高速液/固双相流冲蚀磨损试验机模拟不同试验条件,对改性28Cr高铬铸铁进行了不同冲蚀速度下的抗冲蚀磨损性能研究,着重讨论了该材料奥氏体基体的形变强化机理.研究结果表明:改性28Cr高铬铸铁材料中的高硬度相碳化物发挥了优越的抗磨削作用,同时保护了基体;在34m/s和45m/s冲蚀速度下,后者的冲蚀磨损量及增加速度远大于前者的,同时相变马氏体的相对体积分数从试验前的16 3%分别增加到42 2%和73 6%,冲蚀磨损过程中亚表面变形层内基体产生的相变和位错密度增加等形变强化是该材料耐冲蚀性能优异的另一重要原因.

Mechanisms of Carbide and Matrix of 28Cr Cast Iron During Erosion-Wear Process

The erosion-corrosion tester with high speed of liquid-solid two-phase flow was used to simulate different wearing conditions. The erosion-wear resistance of the newly developed 28Cr cast iron was investigated with varying erosion velocities, and the strain hardening mechanism of the austenitic matrix of the iron was emphatically discussed. The results show that the carbide of 28Cr cast iron can protect the austenitic matrix effectively, and stand against the cutting action from the slurry particles because of its high hardness. The mass loss of the iron at the erosion velocity of 45 m/s is larger than that at 34 m/s. In addition, the relative volume fraction of martensite increases from 16.3% to 42.2% at the velocity of 34 m/s, and to 73.6% at 45 m/s, respectively. It is suggested that the strain hardening, including phase transformation and higher dislocation density, may be another main factor of the excellent wear resistance of the 28Cr cast iron.