Surface Topological Investigation of Seal Bushing by Using Chromium Plating Process

According to utilization functions and environments; various plating methods have been applied on metallic manufactured products to improve some properties such as friction, wear resistance and corrosion; besides mechanical properties such as stiffness, ductility, toughness, fatigue strength, etc. The chromium plating has been commonly used plating technology at manufacturing sector providing a coating of wear resistant chromium with a micro-scaled thickness on metal products. The chromium plating is to gain high toughness, resistance of corrosion, low coefficient of friction and improve some properties of material. Chromium acid solutions consisting of one or more catalytic anions are used for chromium plating. The aim of this study is to investigate the surface roughness parameters for coated and uncoated seal bushing surfaces. The material of seal bushing is AISI 420 steel, which is included in martensitic stainless steels and has quite high tensile strength. After the heating process was applied to the seal bushing, chromium plating was implemented with different currents and periods on the surface of the material. The chromium coating was successfully deposited on a seal bushing surfaces. Experimental data was collected from three different types of the bushing surfaces. After coating process, the finishing methods, such as grinding etc. were implemented. The results indicated that coated surfaces had higher surface roughness values than the uncoated surfaces. According to the results of Wilcoxon test, there were a significant difference between Workpieces B (cutting+turning+chromium plating) and C (cutting+turning+chromium plating+grinding); Workpieces A (cutting+turning) and B.