Tenneco Inc.`s Powertrain Business Unit stated that it has developed an innovative material with superior wear resistance that can greatly reduce the cobalt content, helping engine manufacturers alleviate problems such as limited cobalt quantities and large fluctuations in cobalt prices. .
Heavy-duty high-temperature applications such as heavy-duty turbocharger exhaust relief valve bushings, EGR valves, and high-performance engine seats all need to rely on cobalt to make them wear-resistant in the high-temperature operating range, so these products You can benefit from this innovative material. Tests show that with another sintered steel formulation, the cobalt content in Tenneco sintered materials can be significantly reduced, while the wear resistance will not be affected.
Gian Maria Olivetti, Vice President of Global Engineering Department of Tenneco Powertrain, said: "The shortage and controversy surrounding the mining of cobalt mines and the volatility of cobalt prices mean that the dependence on cobalt must be reduced. Among valve seats and other temperature-affected components, cobalt is still the most effective anti-wear material, but we have extensive experience in powder metallurgy, so we have developed an alternative product, which is a low cobalt content The sintering formula has similar wear properties to the best materials at present. "
Jens Wellmann, Product Manager, Turbocharged Components, Tenneco Powertrain, explained that in EGR valves, turbocharged exhaust pressure relief systems or exhaust valves, the temperature range of bushing applications is from minus 0 ° C to 1000 ° C, This wide range of temperature changes poses challenges to the friction properties of the material. Especially in the low temperature range of 400 ° C, the performance of materials with high cobalt content is better than typical materials without cobalt. Therefore, you need to know "why is the material with high cobalt content and low wear rate?" And "how much cobalt is needed to achieve this effect?"
Tenneco first studied two well-proven existing sintered products: FM-8100 (steel-based cobalt-free sintered material) and FM-T95A (weight-based, 54% cobalt-based sintered material), which can be used It is comparable to casting materials for friction applications. Between these two extreme materials, Tenneco evaluated the wear properties of five materials with different cobalt contents at different temperatures. Research on wear samples shows that, compared with sintered materials without cobalt, Tenneco sintered materials with cobalt form a wear-resistant friction layer at a lower temperature, which answers why the wear rate of materials with high cobalt content Low problem.
By comparing such samples, the researchers conducted the same test on materials with a cobalt content of 17% to 35%, and obtained the answer to the question of how much cobalt is needed to achieve this effect. Based on the test results, Tenneco has developed a new material called FM-T88A, which is a sintered steel with a cobalt content of 17%. It also meets production and quality requirements, including manufacturable and mixed metal powders, and sintering. Craftsmanship, processable materials, and quality assurance.
To verify the results of the initial test, Tenneco collaborated with a mainstream global automaker to conduct tests to compare the wear resistance of FM-T88A with mass-produced materials. The test was conducted on a test platform that simulates the installation of a turbocharger exhaust pressure relief bushing at a temperature of up to 800 ° C. Wellmann said: "The results show that the wear resistance of FM-T88A is significantly reduced at 200 ° C compared to materials without cobalt, which is equivalent to the wear resistance of materials with high cobalt content. At other temperatures, The properties of the new material are very similar to those with high cobalt content. "
Olivetti said: "50% of the world's cobalt mines are currently used to make batteries for electric vehicles, and the demand for this material is increasing year by year. By minimizing the content of cobalt used in high temperature resistant sintered materials, it can help alleviate cobalt. The problem of limited and cobalt price fluctuations, while providing a sturdy product. "