The hardness requirement of the surface of the floating oil seal ring is relatively high, and higher hardness can improve the wear resistance. The material of the floating seal ring is generally high-chromium alloy cast iron. After heat treatment, the hardness of the working end surface is HRC60-72, and the depth of the hardened layer is 0.8~1mm; the metallographic structure is alloy carbide + tempered martensite.

Another important factor affecting the seal is the surface roughness of the floating ring. If the surface roughness of the floating seal ring is large, it will cause increased wear and weakened wear resistance. Under the condition of boundary lubrication, there is enough space to store lubricating oil, which can reduce friction and prolong the service life.