Non-metallic inclusions in gear materials are rated according to the national standard.The non-etched microstructure of the metallographic wear surface of the axial specimen is shown in the figure.
Sampling in the fracture area, polishing non-corrosive state observed under the microscope, rating results of non-metallic inclusions show that non-metallic inclusions in gear material are mainly oxides non-metallic inclusions of “granular + Chain shape”. No other non-metallic substances are found, and the metallurgical quality is good, which is consistent with the conclusion of micro-morphology of the drawing.