Cummins unveils new steel alloy for engines

Cummins announced the development of a new high-temperature steel alloy in collaboration with Oak Ridge National Laboratory (ORNL). The new material will increase the durability and ultimate efficiency of Cummins’ engines and better serve the company’s customers and fleets.

Since starting its alliance with ORNL in 2018, the project to research and develop an alternative steel alloy with significantly improved high temperature oxidation resistance and strength, while maintaining affordability, has provided quick and effective results.

“The partnership with Oak Ridge National Laboratory and development of the new material shows the serious potential for improvements and efficiencies for our engines,” said Corey Trobaugh, Cummins director-applied science and technology, in a statement. “I am extremely proud of the value of work our team has provided and the future improvement it lends.”

Previous materials have limited engine efficiency gains and emissions reductions, and prohibited engineers from extracting more heat from the combustion process, due to materials degrading prematurely from oxidation, scaling, and cracking.

The new material is significantly stronger at elevated temperatures, compared to the most commonly used commercial steel, 4140, and has virtually eliminated those degradation pathways. When comparing the new alloy to 4140 steel, the novel steel alloy exhibited 85 percent greater Ultimate Tensile Strength (maximum stress a material can withstand while being stretched or pulled before breaking) and 143 percent greater fatigue strength (maximum cyclical stress that can be applied for the material to withstand at least 10 million cycles before failure) at 600 C.

Additionally, in an aggressive, long-term engine test of pistons manufactured from the new material, no cracking occurred and very little oxidation or scaling occurred.  The new medium carbon steel offers at least a 50oC increase in temperature capability as compared to current 4140 steels.  Cooperative development of the new alloy was supported by the Department of Energy’s Vehicle Technologies Office LightMAT Program.