Cavitation erosion resistance of sewer pipe materials

Abstract

A cavitating high-pressure water-jet provided the means by which a range of materials (plastics, clay and concrete) were eroded. The measured erosion resistance was a proxy for an initially unknown combination of other properties: strength, fracture toughness, impact resistance, hardness, surface roughness, and limiting service temperature. To ascertain the cause of damage to sewers during high-pressure water-jetting, information about which material properties contributed to the measured erosion resistance under a standard high-pressure water-jetting test were found. The experimental work, and published literature, provided a database of physico-mechanical, physico-chemical, thermal and tribological material properties each of which in turn were correlated with the measured jetting resistance. The properties best correlated with the jetting resistance were: maximum service temperature (R2  =  0ṡ93), elastic modulus (R2  =  0ṡ90), surface roughness (R2  =  0ṡ89), density (R2  =  0ṡ87), and thermal conductivity (R2  =  0ṡ87). The correlation coefficient between jetting resistance and impact resistance (R2  =  0ṡ56) lay just outside the top 10, suggesting that this was not an impact problem but a more complex combination of strength, roughness, and heat dissipation despite actual failures ultimately resulting from fracture (for which toughness was nevertheless also poorly correlated (R2  =  −0ṡ38)). Traditional mechanical wear, abrasion, and erosion resistance parameters (Taber abrasion (R2  =  −0ṡ24), limiting pressure-velocity (R2  =  −0ṡ57), and wear index (R2  =  −0ṡ23)) failed to correlate with the jetting resistance.