Examining new innovations in alloy development
How new innovations in alloy development are advancing slide bearing technologies for combustion engines
In today’s high-performance combustion engines for trucks and passenger vehicles, efficiency and durability are paramount. With over 200 years of industry expertise, Wieland has developed two advanced CuNi6Sn6 alloys – Wieland L66 and Wieland L67 – to push the boundaries of sliding bearing performance. Although these alloys share the same chemical composition, they are processed differently to meet distinct production volumes and application requirements. This article examines the material science behind these alloys, their optimised manufacturing processes, and the resulting advantages in friction, mechanical properties, and design flexibility.
MICROSTRUCTURAL EXCELLENCE
Wieland L66 and Wieland L67 are derived from CuNi6Sn6, a monometallic alloy renowned for its excellent wear resistance and consistent performance. The exceptional tribological properties are achieved through a specialised heat treatment that triggers controlled microstructural transformations. One important phenomenon is spinodal decomposition, which refines the alloy’s microstructure at a very fine scale. This process enhances hardness and abrasive resistance while preserving ductility—a critical balance for sliding bearing applications.
For the rolled product, Wieland L66, delivered as a sheet, the bending process used to form sliding bearing bushes capitalises on the alloy’s inherent strength and can even achieve slightly enhanced mechanical properties. Wieland L66 exhibits impressive benchmarks: a hardness of 255HB, a tensile strength of 810MPa, a yield strength of 735MPa, and an elongation of at least 7%. These values underscore its capability to withstand extreme combustion pressures while maintaining peak performance.
In contrast, Wieland L67 is produced as an extruded tube that is subsequently cut to length and processed further. Although Wieland L67 shows slightly lower mechanical values—with a hardness of 205HB, a tensile strength of 680MPa, a yield strength of 615MPa, and an elongation exceeding 9% – its tribological characteristics remain exceptional and comparable. The phenomenon of spinodal decomposition ensures that both Wieland L66 and Wieland L67 maintain their structural integrity throughout the product lifecycle. As the surface layer wears, a new layer with the same high-performance properties is immediately available, guaranteeing consistent long-term performance.
PROCESS OPTIMISATION
The distinct manufacturing routes for Wieland L66 and Wieland L67 reflect the company’s commitment to innovation and cost-effective production – by leveraging state-of-the-art production facilities and equipment, Wieland ensures that every component produced meets the highest standards of quality, durability, and reliability.
The rolled sheet form of Wieland L66 is ideally suited for bending processes that facilitate large-scale production. This method enables efficient handling and consistent quality control, resulting in slightly enhanced mechanical properties. Sliding bearing bushes manufactured from Wieland L66 are perfectly suited for high-volume applications in engines that require robust performance under extreme combustion pressures. The economical production process ensures that customers benefit from both high quality and cost-effectiveness at scale.
Wieland L67 is produced from an extruded tube, allowing for subsequent cutting and precision machining. This process offers maximum geometric freedom, enabling the creation of highly complex oil grooves and intricate features. The ability to machine Wieland L67 to exact specifications makes it the material of choice for exclusive applications and premium engine designs. When intricate geometries are required, Wieland’s advanced machining capabilities deliver sliding bearing bushes that precisely meet these specialised demands—even when production volumes are lower. This versatility underlines the strength of Wieland L67 in delivering bespoke, high-performance solutions.
FRICTION PERFORMANCE
A key performance metric for sliding bearings is the friction coefficient. Both Wieland L66 and Wieland L67 exhibit friction values slightly below 0.1, which is notably competitive among high-performance bearings. In many conventional systems, friction values tend to hover around or just above 0.1. Therefore, the lower friction values of Wieland’s alloys contribute significantly to reduced wear and lower energy losses during engine operation. This reduction in friction not only improves overall efficiency but also extends the service life of the sliding bearings—vital for engines operating under severe conditions.
ADVANTAGES AND APPLICATIONS
The exceptional performance of Wieland L66 and Wieland L67 in sliding bearing applications is the result of a comprehensive approach that integrates advanced material science with optimised production techniques. The monometallic nature of these alloys means that as the surface layer wears over time, a new layer with identical properties is immediately available. This ensures that sliding bearing bushes maintain their high structural integrity throughout the product lifecycle.
Both Wieland L66 and Wieland L67 are engineered for high-performance internal combustion engines—whether diesel or gasoline. Their advanced mechanical strength and excellent wear resistance allow these sliding bearing bushes to operate reliably under the severe conditions imposed by modern engines. Wieland’s products are trusted by leading global Tier 1 suppliers and OEMs, which further validates the long-term reliability and quality of the company’s solutions.
Wieland takes immense pride in its Made-in-Germany approach, combining time-honoured engineering expertise with cutting-edge technology. Its German production facilities not only deliver consistent quality but also ensure that components meet the rigorous demands of modern combustion engines, durably and reliably.
Wieland’s advanced CuNi6Sn6 alloys, Wieland L66 and Wieland L67, represent a evolution in sliding bearing technology. By harnessing the benefits of controlled spinodal decomposition and leveraging unique production routes – from high-volume bending of Wieland L66 to bespoke extrusion and precision machining of Wieland L67 – the company delivers slide bearing solutions with exceptional mechanical properties and tribological performance.
Dr Joachim Fischer holds the role of technical marketing engineered products at Wieland.
