Abstract：The annular cracking phenomenon was occured on the 20Mn2 semi-trailer axle in the straightening process after quenching and high temperature tempering. The microstructure and composition of the specimens in the annular cracking region were analyzed by means of optical microscope（OM），scanning electron microscopy（SEM） and energy dispersive spectrometer（EDS）.The test results showed that the annular cracking of the semi-trailer axle was related to a large number of aggregated inclusions near the inner wall of the steel tube.
2019, Vol. 37 
