Comparing the Cavitation and Slurry Erosion Wear Resistance of 16Cr-5Ni Stainless Steel With 13Cr-4Ni CA6NM Stainless Steel

Abstract

In the current work, 16Cr-5Ni stainless martensitic cast steel was evaluated in cavitation and slurry erosion tests under different thermal aging treatments (TATs) using an ultrasonic vibratory cavitation apparatus and an in-house-designed jet slurry tribometer. The steel was homogenized at 1100 °C for 40 h and then thermal ageing was performed at 475 °C, 550 °C, and 625 °C for 4 h. The cavitation test results showed a lower wear-rate was obtained under TAT at 475 °C, followed by TAT at 550 °C, and a higher wear-rate was found under TAT at 625 °C. A good correlation was established between hardness and the maximum erosion rate in the cavitation results. In the slurry tests, the jet stream contained a fixed mass fraction of 1.25 wt% sand. The evaluated impingement angles were 45 deg and 90 deg, and better performance was obtained under TAT at 475 °C and TAT at 550 °C. The results for the thermal aging of 16Cr-5Ni were compared with those of traditional CA6NM (13Cr-4Ni) steel, which is widely used in the manufacturing of turbine runners. Under every condition evaluated, 16Cr-5Ni presented a cavitation erosion resistance value higher than that of CA6NM, and the slurry erosion resistance of both steels was very similar when 16Cr-5Ni under TAT at 475 °C or 550 °C was compared with CA6NM. Therefore, 16Cr-5Ni stainless martensitic cast steel could be another alternative to the promising results obtained for the manufacturing of turbine runners.