Electrolytic polishing of stainless steel
General details and applications:
Electrolytic polishing is an electro-chemical process used mainly for chromium and nickel-chromium steel types.
Carbon steel types, low-alloy steels and other ferrous materials can, in principle, also be treated with this process, although the same decorative effects cannot be achieved as with nickel-chromium steels.
Electropolishing is a metal-eroding process in which the product acts as the cathode. It is possible to work with high and low current densities in this electrolyte.
The condition of the material and the surface structure are decisive factors for achieving an optimal electropolished effect. Alloying elements, material properties as a result of processing (hardness, etc.) also have a perceptible impact on the erosion of metal during electropolishing. The suitability of the material surface and structure can only be determined on the basis of appropriate sampling.
Electropolishing is a fine finishing process which is not intended to remedy dispersions of unpolishable materials, rolling defects, mechanical damage, etc. Coarse or rough surfaces should preferably be pretreated using appropriate mechanical methods.
The process of electro-chemical metal erosion causes erosion to take place at the points with the most favourable current flow. This fact makes electropolishing particularly suitable for precision deburring and light rounding-off work, especially when high current densities are employed. The shape and the connection of the flash to the workpiece are the determining factors for deburring. By using constructive cathodes it is possible to effect defined metal erosion, although only within the range of a macro-erosion.
Our programme also includes special finishing processes for apparatus engineering and electropolishing for the inside surfaces of tanks.
Fields of application:
Articles for the medico-technical sector:
Components for medical technology are subjected to electrolytic polishing to achieve an absolutely plane surface in microprofile.
The objective of having such a smooth surface is to prevent the adhesion of diverse medicinal liquids with which the electropolished parts may come in contact. As a result, the parts are easier to clean and/or sterilize. The optical effect also plays an important role.
Components in this sector, e.g. handles for saucepans and frying pans, are made mainly of stainless steel sheet. After the mechanical production process these parts have sharp edges and an unattractive appearance. Electropolishing deburs the parts and provides them with an attractive, high-gloss surface.
Screws, bolts, nuts and other small components made of stainless steel are usually electropolished for optical reasons. Apart from achieving a bright surface, this treatment also protects against later corrosion, because miniscule steel particles from previous tooling are removed during the process.