High Strength Aluminum Bearing Alloy with Increased Fatigue Resistance
2022-01-0411
03/29/2022
- Event
- Content
- Aluminum-tin alloy lined bimetals have traditionally been utilized in rod and main bearing applications in light duty gasoline engines due to their combination of strength with soft-phase properties, such as embeddability and conformability. The load carrying capability of aluminum-tin alloys can be further increased by applying a polymer overlay, but recent advances in engine design, to improve efficiency and reduce CO2 emissions, have resulted in maximum specific load requirements beyond the performance limits of current aluminum-tin products. In these instances, the standard option would be to specify a lead-free bronze-based bearing solution, which has increased strength, but necessitates greater weight and brings a significant cost disadvantage over aluminum products. To address these problems, MAHLE have developed a high strength aluminum lined bimetal for use with a polymer coating, which offers a significant advantage in load carrying capability over traditional aluminum-tin alloys. The new product utilizes a AlMn1Mg1 alloy, which is roll bonded to steel and heat treated prior to bearing manufacture. Bearing fatigue testing demonstrates a 20% increase in fatigue resistance from 103 MPa validation load for the conventional aluminum-tin system to over 124 MPa for the newly developed product. A 900-hour thermal shock engine test on a Euro 6 inline 6 heavy duty diesel engines demonstrated good performance in an application which currently utilizes a bronze-based bearing solution. An evaluation of seizure behavior shows comparable performance to existing products. Overall, the new product successfully achieves the aims of increasing the load carry capability, which maintaining the benefits inherent in an aluminum substrate material.
- Citation
- Campbell, S., Morais, P., and Stearns, J., "High Strength Aluminum Bearing Alloy with Increased Fatigue Resistance," SAE Technical Paper 2022-01-0411, 2022, .