Abstract: By means of metallographic examination,X-ray diffraction,X-ray photoelectron spectroscopy,hardness and density testing,etc.,the wedge unknown material of a high speed overrunning clutch was analyzed. With comprehensive analysis to the testing results,the sample material was determined as GCr15. The testing also showed that the material was quench-hardened,and the chromized layer with depth of 6.8-8.3 μm on sample surface raised wear resistance and corrosion resistance of the material.