The Influence of Steel Composition on the Formation and Effectiveness of Anti-wear Films in Tribological Contacts

Abstract The effectiveness of antiwear additives in laboratory tests is commonly evaluated using specimens made AISI 52100 through-hardened bearing steel. However, many lubricated machine components are steels with significantly different material compositions, which raises an important practical question whether the performance these other steel types from that established 52100. To help answer this question, paper investigates influence composition on formation and films. Four used tribological applications, namely steel, 16MnCr5 case-carburised gear M2 high speed 440C stainless tested rolling-sliding, ball-on-disc contacts three custom-made oils, one containing ZDDP two ashless additives. relative their boundary films was assessed by measuring thickness associated wear friction over 12 h rubbing at specimen roughness levels. For it found film not influenced or surface roughness. A similar tribofilm thickness, final observed all four steels. No measurable observed. By contrast, for tribofilms strongly composition, particularly higher exact trends vs relationship depended specific chemistry additive (ester-based acid-based) but general, to promoted whilst retarded formation. This behaviour attributed presence alloying elements ability extract metal cations surfaces support growth a tribofilm. In cases were thicker rougher, produced than those formed unlike ZDDP, blends generally significant wear, results indicate ensure reliable given component, should be matched present machine.