A Novel Process for Manufacturing High-Friction Rings with a Closely Defined Coefficient of Static Friction (Relative Standard Deviation 3.5%) for Application in Ship Engine Components

Abstract

In recent years, there has been an increased uptake for surface functionalization through the means of laser surface processing. The constant evolution of low-cost, easily automatable, and highly repeatable nanosecond fibre lasers has significantly aided this. In this paper, we present a laser surface-texturing technique to manufacture a surface with a tailored high static friction coefficient for application within driveshafts of large marine engines. The requirement in this application is not only a high friction coefficient, but a friction coefficient kept within a narrow range. This is obtained by using nanosecond-pulsed fibre lasers to generate a hexagonal pattern of craters on the surface. To provide a suitable friction coefficient, after laser processing the surface was hardened using a chromium-based hardening process, so that the textured surface would embed into its counterpart when the normal force was applied in the engine application. Using the combination of the laser texturing and surface hardening, it is possible to tailor the surface properties to achieve a static friction coefficient of ≥0.7 with ~3–4% relative standard deviation. The laser-textured and hardened parts were installed in driveshafts for ship testing. After successfully performing in 1500 h of operation, it is planned to adopt the solution into production.

Influence of Laser Parameters on the Texturing of 420 Stainless Steel

“…According to the authors, as the mechanism that removes material in this type of laser is melt ejection, the molten pool may be deposited inside the wall of the groove and on the edge of the ablated region, reducing the width of the cavity created. Regarding the depth, as expected, it tends to increase with the number of passes [18,32]. The increase in laser power has a significant impact on the width and depth (cases analysed: P64 s2000 n8 l50 and P100 s2000 n8 l50).…”

“…Laser surface texturing, in particular, has become one of the major focuses of research and studies due to the flexibility of laser sources, the relative ease of automation, high precision, the relatively low cost and maintenance, and the commercial availability of robust laser systems [18,19]. Surface texturing is a manufacturing technology used to create dimples or grooves on the material's surface [20].…”

A Review on Friction Reduction by Laser Textured Surfaces in Internal Combustion Engines

“…There is a need for surfaces that create high static friction to transfer power, and are protected against overload and failure in marine applications. For this purpose, Gora et al developed a process for laser surface texturing and chromium carbide coating [11].…”