Research of the Carrying Capacity of Bainitic Ductile Iron Gears Cao Renzheng Guan Zhuo ABSTRACT This paper is through the investegation of the result of life test over one hundred and thirty pairs of Bainitic Ductile Iron gears, perfectly prored that the tooth strength of gears made from this mate- rial is the highest of all sort ductile iron gears.Thereby it possesses a broad developing prospect. Authors have Conducted the pitting and bending durability test of gear tooth with tow sort materials of possessing ourselves,features ducctile iron -Copper-Malybdenum and Vanadium-Tiandium Bainitic and abtained the respective functions of S-N curve with reliability R=0.99 and the relevant value of fatigue limit stress om.Therefore it would supply the system datum to the design and manufacture of this sort gears and also would offer a referance for the "principle for the calcu- lation of tooth strength of spur and helical gears”of“ISO”When it augment the inadequate datum of fatigue limit stress of ductile iron gears. Authors arc applying this datum abtaining from above test to tackle the practical are problem of gears in the industry also abtaining a good effects 70一 。 ， 一 一 一 一 ，一。 “ 一 ‘ ” 位 爪 “ 节