Development of New Alloy Steel and its Application for both high Fatigue Strength and high Machinability by Utilizing New Inclusion Morphology Control Technology

摘要

Diesel products are faced with emission regulations, fuel efficiency improvements, and increasing horsepower. To address these issues, the fuel injection pressure will be increased. To achieve high pressure fuel injection, high fatigue strength material is required. In order to keep high production efficiency of the parts, good machinability of the material is also required. However, good fatigue performance and good machinability usually contradict each other as a general rule. As a result of our study, an alloy steel with both good machinability and high fatigue strength has been developed by morphology control of the inclusions. The new morphology control technology for inclusions in the steel is applied to the diesel Common Rail product. The common rail has achieved high fatigue strength performance. Furthermore, its machinability is equal to or greater than that of general steel.