In order to study the change of contact characterizations of end faces in mechanical seal running-in

taking into account the difference between real micro contact area and micro contact cross-sectional area of end faces of mechanical seals

the expressions of the micro-contacting areas related to the critical elastic and plastic deformations were revised.The expressions of elastic contact area ratio

elastic-plastic contact area ratio and plastic contact area ratio for mechanical seals were derived.Running-in tests of B104a-70 mechanical seals were made with water as test medium.Test temperature was 20℃. Test pressure was 0.5 MPa. Spring pressure was 0.15 MPa. Rotating speed was 2900 r·min-1.The results showed that the end face of the soft ring tended to be smoothened rapidly and its wear rate decreased quickly in running-in.The contact characterizations between end faces of mechanical seals changed greatly.The normalized real contact area increased from 0.00348 to 0.00567. The elastic contact area ratio increased from 0.716 to 0.822.The elastic-plastic contact area ratio decreased from 0.231 to 0.128. The plastic contact area ratio decreased from 0.053 to 0.050.