Assessing the Impact of Surface Roughness on Wear Resistance of Hydraulic Pump Components

Thesis Abstract

Hydraulic pump components are critical in fluid power systems, where their operational efficiency and longevity are significantly influenced by surface characteristics, particularly surface roughness. Excessive or uneven surface roughness has been linked to increased wear rates, leading to reduced service life, higher maintenance costs, and system inefficiencies. Despite advancements in manufacturing and finishing technologies, a comprehensive empirical understanding of how surface roughness specifically impacts wear resistance in hydraulic pump components remains limited. This study aims to systematically assess the relationship between surface roughness and wear resistance in hydraulic pump parts, with particular attention to plunger and barrel surfaces subjected to operational stresses. The core objectives are to quantify surface roughness parameters of manufacturing samples, measure their corresponding wear rates under simulated operational conditions, and identify critical roughness thresholds that significantly influence wear behavior. The research adopts an experimental design complemented by quantitative analysis. A total of 60 hydraulic pump component samples, specifically 30 machined steel plungers and 30 barrels, were prepared using controlled manufacturing processes to produce diverse surface roughness profiles. Surface roughness parameters, including Ra (arithmetic mean roughness), Rz (mean peak-to-valley height), and Rq (root mean square roughness), were measured with a contact profilometer following ISO standards. Wear testing was conducted using a custom-designed hydraulic fatigue tester that simulates real operational conditions, applying cyclical loads and fluid flow within parameters consistent with typical hydraulic system environments. Wear was evaluated through mass loss measurements using precision electronic balances, surface profilometry post-test, and microscopic analysis. Data analysis involved descriptive statistics, Pearson correlation coefficients, and regression analysis to model the influence of surface roughness parameters on wear rates, complemented by ANOVA tests to determine statistical significance. It is anticipated that the study will reveal a strong positive correlation between higher surface roughness parameters and increased wear rates, with specific roughness thresholds identified beyond which wear accelerates markedly. These findings are expected to demonstrate that optimizing surface finish processes can substantially enhance the wear resistance of critical pump components, thereby extending their service life and improving overall system reliability. Furthermore, the study aims to establish empirical models that predict wear behavior based on measurable surface parameters, contributing valuable insights for manufacturing practice and maintenance planning. This research offers a significant contribution to the body of knowledge by filling gaps related to quantitative relationships between surface roughness and wear resistance in hydraulic pump systems. It provides a scientific basis for establishing industry standards and best practices for surface finishing techniques aimed at wear mitigation. Theoretically, the study supports the application of wear and surface interaction models rooted in tribology, such as the Archard wear law, enhanced with empirical data specific to hydraulic systems, thereby refining predictive capabilities in component longevity assessments. In conclusion, the study underscores the critical importance of surface finish quality in hydraulic components and advocates for the integration of precise surface roughness control during manufacturing processes. It recommends adopting advanced surface finishing techniques, such as abrasive flow machining or laser polishing, to maintain surface roughness below identified critical levels. Future research should explore the synergistic effects of surface coatings and material properties on wear resistance, broadening the scope of maintenance technology improvements in hydraulic industrial applications.