Essentially, the passivation process makes stainless steel more resistant to corrosion or rusting. Stainless steel is never 100% “rust”-proof, but with proper passivation it will be as close as possible.
Passivating stainless steel removes microscopic iron particles that may have been deposited during manufacturing steps as well as those within the part that are close to the surface. By removing the iron, the stainless steel’s chromium reacts with oxygen, forming an invisible, protective layer. To qualify as “stainless,” steel must have a chromium content exceeding 10.5 percent.
What Does Passivation Not Do?
In general, passivation does not discharge existing stains or rusting. That requires other methods, such as light abrasion, bead blasting, tumbling and sometimes sanding. Passivation also does not remove weld scale, black oxides and burn marks from welding.
How Does Stainless Steel Passivation Work?
Stainless steel passivation is a preventative measure that draws the free irons away from the stainless steel or titanium part that could cause corrosion.
To be classified as “stainless,” steel must have a chromium content exceeding 10.5 percent. The chromium helps the steel’s iron portion resist combining with oxygen, which is how rust is generated. stainless Steel can rust, but does so much less than other alloys.
Passivating your stainless steel will increase your parts resistance to corrosion and provide a better, more aesthetically pleasing product for your customers. Since stainless steel is expensive, passivation is well worth the investment.
How Does Chemical Passivation Work?
RP Abrasives’ chemical passivation process uses acids and deionized water to render a steel surface “passive,” and thus less susceptible to corrosion or rust due to environmental factors such as air or water. Many of our existing medical and food industry customers had requested that we provide passivation services, since they are often required within their own industries to have it done. As we began to expand our capabilities to meet our customers’ needs, we soon found that we could provide this service on its own.
We use a citric acid based solution to passivate stainless steel and titanium because it’s the most effective and environmentally friendly option available. It is very selective in removing just the free irons on or near the surface of a part.