The paper present the investigation on the effect of temperature, time and current density on surface roughness in electropolishing process on 316L stainless steel. The cathode material under study was 316L stainless steel. The electrolyte was composed of sulfuric acid, phosphoric acid, and DI water. Full factorial design method was used. ANNOVA technique has been used to assess the quantitative influence of the different process factors of the EP. The surface roughness will be obtained up to 0.03 µm in this experiment whose surface roughness before electropolishing is 0.17 µm hence surface roughness reduction is 0.14 µm.
Keywords: Electropolishing, design of experiment, full factorial design, surface roughness.
1. Introduction …show more content…
Lee and Lai (2003) have reported that the electropolishing is very effective technology to improve the corrosion resistance of SS 316 stainless steel. The electrolyte used in this study is phosphoric acid, sulphuric acid, glycerin, and distilled water. They found that the electrolyte gap was 5mm and polishing time was 5 min produced better surface finish. The surface roughness improvement by more than threefold was seen. These values may be different for different variables such as electrolyte and cathode material. Further the result on corrosion resistance was also interesting. They found significant 60-80% improvement of corrosion resistance after electropolishing . Kao and Hocheng (2003) have reported using grey relational analysis optimizing the electropolishing of 316L stainless steel with multiple performance characteristics. Electrolyte was used phosphoric acid, sulphuric acid, glycerin, and water .
2. Methodology of experiment
2.1 Work material
The work material used for electropolishing experiment were 316L stainless steel. The specimen size was 40mm (length), 20mm (width), and 1mm (thickness). The chemical composition of 316L stainless steel shown in Table 1.
Table 1 Chemical composition of 316L stainless steel
Ele. C Si Mn S P Cr Ni
% Wt 0.027 0.621 1.146 0.017 0.028 16.357 10.552 …show more content…
The influence of EP parameters on the surface roughness is using main effect plot as shown in Fig.2. The surface roughness decrease with increase in temp. When time increase from 9 min to 12 min there is decrease in surface roughness but from 12 min to 15 min there is no change in surface roughness. In third case, when current density increase from 0.0054 A/mm2 to 0.0058 A/mm2 , there is decrease in surface roughness but from 0.0058 A/mm2 to 0.0062 A/mm2 again surface roughness will be