Sealing ring, esp. for floating or sliding seals where mild steel ring coated with tungsten carbide by plasma spraying is used to replace expensive abrasion-resistant cast iron ring

摘要

Two sealing rings in sliding contact with each other are pressed together by two holding elements made of an elastomer, e.g. O-rings pushed against the sealing rings. The sealing surface of each sealing ring is coated by plasma spraying with a metal-ceramic layer contg. tungsten carbide and nickel, and with a thickness of 0.07-0.15 mm, pref. 0.09-0.12 mm. The sealings rings are pref. made of a low carbon steel which is cleaned by shot blasting, and then coated by plasma spraying. The coating is pref. lapped, and then has a final thickness of 0.07-0.15 mm, esp. 0.09-0.12 mm. Esp. for drive units, gearboxes or bearings on vehicles used in the construction industry, where the sealing rings are exposed to abrasive earth and sand, e.g. on excavators or vehicles with endless tracks. Conventional sealing rings are made of an expensive alloy cast iron contg. several alloying elements to provide a hardness of HRC 65-70. The invention replaces this costly iron with a low carbon steel ring, which is only coated on its working surface with a hard layer, providing long working life.