Electropolishing of Stainless Steel in Laboratory and Industrial Scale

Abstract

Transposing the process scale from laboratory to industrial conditions is a difficult issue that applies to many sectors of the industry. As far as electropolishing of stainless steel is concerned, the limitations connected with a significant increase in the area of electropolished surface should be considered, along with the possibility of defects that may emerge. This paper compares the results of electropolishing of stainless steel in the laboratory and in industrial conditions. For the analyzed conditions, it was determined that the best results, both in laboratory and industrial conditions, were obtained at temperature of 35 • C and current density of 8 A·dm −2 . High temperatures resulted in the emergence of defects on the surface, in particular for industrial samples. The defects were visualized by metallographic images with Nomarski contrast and atomic force microscopy. X-ray photoelectron spectroscopy tests were used to analyze the composition of the passive layer on the electropolished surfaces.

A multi-factorial mathematical model for the selection of electropolishing parameters with a view to reducing the environmental impact

“…In order to achieve the same final total level of weight loss of samples for both baths, Solution B had to be operated for over 1200 A min longer, which accounted for nearly 30% of the total operation time. The weight loss analyses in laboratory conditions produced very similar results to those obtained in industrial conditions using the same process bath 32 . Thus, it is possible to predict the expected weight loss in industrial conditions, even for electropolished elements of a much larger surface area.…”

Electrochemical Polishing of Austenitic Stainless Steels

“…The review of literature on the surface processing of metals revealed that elements made from chromium and nickel steel may be electrochemical polished with baths that contain sulphuric acid (VI), orthophosphoric acid (V) [44], triethanolamine [45][46][47] and ethylene glycol, oxalic acid, and acetanilide [21]. Stainless steel may also be electrochemical polished in a solution consisting of sulphuric acid (VI) and citric acid, as well as of sulphuric acid (VI), phosphoric acid (V) and lactic acid [48,49].…”

“…Surface defects were presented after the electropolishing process in industrial conditions [46]. A bath containing H 3 PO 4 and H 2 SO 4 and triethanolamine contaminated in industrial conditions was used for the tests, and the iron ions contamination was about 3% by wt.…”

Surface Treatment Technology of Metals and Alloys

“…Technology of Metals and Alloys. All the presented subjects are multidisciplinary, and include shot peening treatment [1], electropolishing [2], low-pressure carburizing [3], oxi-nitrocarburization [4], abrasive blasting [5], hydrothermal treatments [6], laser cladding [7], plasma modification [8], low-temperature vacuum carburization [9], plasma electrolytic oxidation [10], and thermoreactive deposition [11].…”

“…It was found that the best results, both in laboratory and industrial conditions, were obtained at a temperature of 35 • C and a current density of 8 A•dm −2 . It was also noted that high temperatures resulted in the emergence of defects on the surface, in particular for industrial samples [2].…”