Hardness Test of Coal Mill Gear

Rockwell hardness tests were carried out on the surface and center of the intermediate shaft sun wheel at different points.

The microhardness gradient curve of the non-worn surface of the sun gear teeth is shown in the figure.

According to the national standard metal material Vickers hardness test method, the microhardness of the non-segregation area and the segregation area of the sun gear material were tested and compared with the analysis results.

According to the microhardness test in Table 5 and the results in Figure 9, the hardness of the gear surface and the center part are basically the same, which indicates that the tooth part of the intermediate shaft has not undergone surface hardening and is in accordance with the results of metallographic structure analysis.In addition, the results of micro Vickers hardness test show that the hardness of segregation zone of gear material is significantly higher than that of non-segregation zone.