Corrosion-erosion of nitrogen bearing martensitic stainless steels in seawater-quartz slurry

摘要

AISI 410S stainless steel was nitrided at 1473 K in N2 atmosphere, direct quenched and tempered at temperatures between 473 and 873 K. Martensitic cases with circa 0.52 wt.% N at the surface were obtained. Corrosion-erosion tests were carried out in slurries composed by quartz particles and tap or substitute ocean water. The concentration of solids, the impact angle and the pH of solution were fixed, while the temperature, surface changes and mass losses were monitored during the tests. Quenched and tempered ATSI 410 and 420 stainless steels were used as comparison materials. The results showed that the erosion resistance and the corrosion-erosion resistance of the nitrided steel tempered at 473 K were higher than those of the AISI 410 and 420 steels tempered at the same temperature. This behavior was due to the higher hardness and better intergranular, pitting and generalized corrosion resistance of the nitrided alloy. The synergism between corrosion and wear was more important in the AISI 410 and 420 samples.