Electropolishing is an electrochemical finishing process for stainless steel. The easiest way to understand it is as plating run backwards.
The principle
In electroplating, the part is the cathode and metal deposits onto it. In electropolishing, the part is the anode and metal dissolves off it. Because current density is highest at the microscopic peaks on the surface, those peaks dissolve preferentially. The surface levels out from the top down.
Two things result. The surface gets smoother and brighter. And because the process preferentially removes surface contaminants and embedded iron, it leaves behind a cleaner, more uniform passive layer, which improves corrosion resistance.
Electropolishing vs mechanical polishing
| Mechanical polishing | Electropolishing | |
|---|---|---|
| Mechanism | Physical abrasion | Electrochemical dissolution |
| Uniformity | Hard to reach recesses evenly | Uniform, reaches internal geometry |
| Residual stress | Introduces stress and smearing | Stress free, no smeared metal |
| Batch work | Labor scales with part count | Scales well |
They are often combined: mechanical polishing to level the surface, then electropolishing to finish it.
Where it is used
Foodservice equipment and kitchenware, where cleanability matters. Medical components, where the passive layer matters. Decorative stainless hardware, where appearance matters. All three benefit from the same mechanism.
FAQ
Which is better, electropolishing or mechanical polishing?
For complex geometry, batch work, and corrosion performance, electropolishing. For heavy leveling of a rough surface, mechanical first. Most demanding parts get both.
Does it really improve corrosion resistance?
Yes. It removes surface defects and free iron and leaves a more uniform passive film.
Which grades can you process?
Common austenitic grades such as 304 and 316. See stainless steel electropolishing. Request a quote.