Aerospace and orbiting satellite

1. 1. M50NiL bearing steel
2. The speed requirement of aircraft engine was increasing during the 25 years from 1955 to 1980, and its dn value has reached 2.5 million. After the 90s, the high speed and high temperature of aircraft engine had higher requirements for the used bearings. However, even though the special used high temperature bearing steel is adopted, such as M50, 18-4-1, and various derived steels from 14Cr-4Mo, such as CRB-7 and GB-42, the current bearing steel, can continue to work when the temperature was significantly higher than the engine bearings. While another very important limiting factor, which refers that the bearing ring is crisp and easy to break at ultra high speed, is to find out a bearing steel type with toughness of M50 bearing steel and better breakage. MRC bearing corporation of NTN carried out a series of research work based on the support of U.S. Air Force and finally chose M50NiL. In addition to the improved fracture toughness, M50NiL has very good microstructure and fatigue strength comparing with other bearing materials with high-temperature hardenability. Since one of the causes is the large carbides particles containing in M50iL, this steel type is not sensitive to fatigue crack. Nowadays, NTN Corporation is in the leading position of the country as the bearing made from M50NiL has been used in 12 types of consistent aircrafts.