Comparison and analysis of responses of four materials applied in ocean engineering to the treatment of waterjet cavitation
In order to compare cavitation erosion resistance of four materials used in ocean engineering,an experimental work was carried out using a cavitating jet erosion experimental rig conforming to the ASTM G134-2023 standard with clean water as the circulating medium and its temperature maintained constant.Materials of A1070,NW2200,CAC402 and SUS316L were selected for comparative experimental study.The mass loss of the target specimens was measured.The morphology of target specimen surfaces was observed.The grain boundary orientations were inspected.The cross-sectional hardness was measured and analyzed.At a cavitation number of 0.14 and an inlet pressure of 20 MPa for the cavitation erosion chamber,the optimum standoff distance of 16.0 mm was obtained.The results show that under the condition of 19.0 mm standoff distance,the cumulative mass loss of A1070 specimen is reduced by about 14%compared to the standoff distance of 16.0 mm(the cavitating waterjet acting time is 5 min).For the SUS316L,NW2200 and CAC402 specimens,they enter the cavitation erosion stabilization stage after elapse of about 320,110 and 70 min,respectively,and the corresponding cumulative mass loss rate is 0.14,0.30 and 0.45 mg/min,respectively.The electron backscatter diffraction analysis indicates that while the jet cavitation causes cavitation erosion,it causes presence of small-angle grain boundaries near the impacted surface where there appears relatively high stress at the same time.The hardness near the specimen surface increases as the cavitation action time extends,and the material removal makes the hardening effect extend into the specimen.The research can provide reference for the design and manufacturing of marine equipment components.
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