YL
Y. Liu
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1
The wear of pipelines, used in slurry transport, results in high costs for maintenance and replacement. The wear mechanism involves abrasion, corrosion, impact, and the interaction among them. In this work, we study the effect of impact on the wear mechanism and wear rate. Results show that when the effect of impact is small, the wear mechanism is dominated by electrochemically induced surface modification, which leads to a lower wear rate in a corrosive environment than in a non-corrosive environment. By contrast, when the effect of impact is large, the wear mechanism is drastically altered. In that regime plastic deformation is important. The influence of corrosion in the high impact regime can be neglected. Our findings show the importance of including impact effect in the distinction of wear of slurry pipes
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The wear of pipelines, used in slurry transport, results in high costs for maintenance and replacement. The wear mechanism involves abrasion, corrosion, impact, and the interaction among them. In this work, we study the effect of impact on the wear mechanism and wear rate. Results show that when the effect of impact is small, the wear mechanism is dominated by electrochemically induced surface modification, which leads to a lower wear rate in a corrosive environment than in a non-corrosive environment. By contrast, when the effect of impact is large, the wear mechanism is drastically altered. In that regime plastic deformation is important. The influence of corrosion in the high impact regime can be neglected. Our findings show the importance of including impact effect in the distinction of wear of slurry pipes
The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.
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The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.
A better understanding of the wear mechanism of materials is essential to selecting suitable materials to prolong service time and reduce costs. Wear resistance is not an intrinsic material property but a response to a system including multiples parameters determined by the material, the counter body, the load condition, and the environment. Wear is a common cause of materials degradation, as well as Corrosion. When mechanical wear and corrosion co-exist, they interact with each other and, often, enhance each other, resulting in faster material failure than the situation where only a single factor exists. This thesis presents the study of the interaction between corrosion and wear with the goal of obtaining a better understanding of the wear mechanism to guide the material selection. To study the wear mechanism, a pin on disc tribometer was employed to precisely control the load, rotational speed, and corrosion environment. A potentiostat was also used to provide well-defined corrosion environment (corrosion is quantified by the current and potential). By connecting the pin on disc with a potentiostat, a well-controlled mechanical and chemical (electrochemical) system was employed to perform wear experiments. Results show that the influence of corrosion on wear is found to be much more complex than simply enhancing, as proposed at the onset of my PhD research. The new findings in this thesis show that the influence of corrosion is highly dependent on the specific situation and the corresponding wear mechanism. Corrosion may increase wear rate when the process is governed by cyclic formation and removal of surface corrosion products. Corrosion may decrease wear rate when the process is governed by the galvanic micro coupling effect. Corrosion may not influence wear rate when the process is dominated by impacting.
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A better understanding of the wear mechanism of materials is essential to selecting suitable materials to prolong service time and reduce costs. Wear resistance is not an intrinsic material property but a response to a system including multiples parameters determined by the material, the counter body, the load condition, and the environment. Wear is a common cause of materials degradation, as well as Corrosion. When mechanical wear and corrosion co-exist, they interact with each other and, often, enhance each other, resulting in faster material failure than the situation where only a single factor exists. This thesis presents the study of the interaction between corrosion and wear with the goal of obtaining a better understanding of the wear mechanism to guide the material selection. To study the wear mechanism, a pin on disc tribometer was employed to precisely control the load, rotational speed, and corrosion environment. A potentiostat was also used to provide well-defined corrosion environment (corrosion is quantified by the current and potential). By connecting the pin on disc with a potentiostat, a well-controlled mechanical and chemical (electrochemical) system was employed to perform wear experiments. Results show that the influence of corrosion on wear is found to be much more complex than simply enhancing, as proposed at the onset of my PhD research. The new findings in this thesis show that the influence of corrosion is highly dependent on the specific situation and the corresponding wear mechanism. Corrosion may increase wear rate when the process is governed by cyclic formation and removal of surface corrosion products. Corrosion may decrease wear rate when the process is governed by the galvanic micro coupling effect. Corrosion may not influence wear rate when the process is dominated by impacting.