利用磁致伸缩空蚀试验机研究了高氮钢在蒸馏水、0.5 mol/L NaCl和0.5 mol/L HCl溶液中的空蚀行为, 利用SEM观察了试样表面和截面的空蚀形貌, 对静态和空蚀条件下的极化曲线进行了测量. 结果表明, 高氮钢在3种介质中空蚀8 h后的失重随着介质的腐蚀性增加而增加, 失重率曲线存在一个孕育期, 孕育期随着介质腐蚀性的增加而缩短; 高氮钢的空蚀破坏以韧性断裂为主, 在HCl溶液中, 由于H的存在, 促进了位错的滑移, 导致裂纹失稳扩展, 裂纹扩展并相互连接造成材料的空蚀抗力降低.

The cavitation erosion (CE) is a serious problem in engineering components in contact with a liquid in which the pressure fluctuates. The CE resistance of material is related to the microstructure, hardness, work hardening ability, superelasticity and superplasticity, or strain or stress induced phase transformation of material. The high nitrogen stainless steel (HNSS) is attractive for its low cost in application where a combination of good strength and toughness, high work hardening capacity, and corrosion resistance is required. These attractive properties cause the nitrogen alloyed stainless steels to be the good candidates with relatively high CE resistance. In this work, the CE behavior of HNSS in distilled water, 0.5 mol/L NaCl and 0.5 mol/L HCl solutions was investigated on the base of mass loss and polarization curve. The micrographs of damaged surface were observed by using SEM. The results showed that the cumulative mass loss of HNSS after subject to CE for 8 h was the highest in 0.5 mol/L HCl solution and lowest in distilled water. There existed an incubation period in mass loss rate curve and the incubation period shorted with the increase of the corrosive of tested solution. The plastic fracture was the dominant damage mode of HNSS subject to CE condition. The plastic deformation and dislocation motion of HNSS were facilitated by diffusion of hydrogen in HCl solution, therefore the initiation and propagation of crack were accelerated and removal of materials was accelerated by propagation and connection of cracks.