How Electropolishing Improves Corrosion Resistance

Category 04 · Improve Part Life and Performance

Corrosion Resistance

An electropolished surface outperforms passivation alone by up to 30× — proven through 888–1,000 hours of ASTM B-117 salt spray.

30× vs. passivation
Salt spray comparison. Left, a passivated stainless part under ASTM B-117 salt spray showing heavy rust — weaker protection, rust forms over time. Right, the same part electropolished, still bright, with a chromium-rich passive film and no flash attack. Centre: 30× vs. passivation, 888–1,000 hours ASTM B-117.
Why it outlasts passivation
Up to 30× improvementindependent ASTM B-117 testing: 888–1,000 hours with no rust
Chromium-rich surfacedissolving the iron-rich layer leaves a stronger passive film
Defects removed, not cleanedthe cracks and inclusions where rust starts are gone entirely
No flash attacksafe on sulfurized grades like 303, where nitric passivation risks damage

✓ Meets ASTM B912 — and satisfies passivation requirements in the same operation. Auger (AES) analysis of Able-polished 316L shows chromium enrichment 20–25 Å deep with Cr/Fe ratios above 1.5 — the surface chemistry behind the salt-spray results.

Where corrosion starts — 8 common sources on "stainless" parts
  • Carbides from machining and stamping
  • Embedded scale
  • Grinding compounds
  • Sulfonated lubricants
  • Steel totes and pans
  • Contaminated buffing wheels
  • Polishing compounds
  • Heat effects from welding
Every one of these leaves iron or contamination in the surface — and every one dissolves along with the surface layer during electropolishing.
Compare: passivation vs. pickling vs. electropolishing
Point of comparison Passivation Pickling Electropolishing
Removes surface contaminants ✓ Yes ✓ Yes ✓ Yes
Typically includes pre-cleaning / degreasing ✓ Yes ✓ Yes ✓ Yes
Effective for sizing ✗ No ✗ No ✓ Yes
Microscopic precision ✗ No ✗ No ✓ Yes
Consistent, uniform results ✓ Yes ✗ No ✓ Yes
Improves fatigue life ✗ No ✗ No ✓ Yes
Improves corrosion resistance ✓ Yes ✗ No ✓ Yes
Deburrs the metal surface ✗ No ✗ No ✓ Yes
Removes microcracks ✗ No ✗ No ✓ Yes
Removes heat tint ✗ No ✓ Yes ✓ Yes
Removes oxide scale ✗ No ✓ Yes ✓ Yes
Improves microfinish ✗ No ✗ No ✓ Yes
Cleans welds effectively ✗ No ✓ Yes ✓ Yes
Passivates parts ✓ Yes ✗ No ✓ Yes
One pass replaces separate deburr, clean, and passivation steps. On corrosion specifically: electropolishing is up to 30× more effective than passivation alone — 888–1,000 hours of ASTM B-117 salt spray with no rust (see the case files above) — and carries no flash-attack risk on sulfurized grades like 303. Source: Able technical guide, Passivation, Pickling or Electropolishing.
Where it matters most
MarineOil & gasFood & beverageAerospaceMedical
The full story — problem & solution
The problem

Embedded free iron, surface imperfections, and contamination left by machining become initiation sites for corrosion — even on stainless steel. Passivation removes contaminants chemically but leaves the damaged surface profile in place.

How electropolishing solves it

Electropolishing removes the entire affected surface layer — contaminants and the imperfections that harbor them — leaving a chromium-rich, passive surface that outperforms raw and passivated parts in salt spray testing, and can be specified to meet passivation requirements in one step.

From the field

“At SPM, we machine a lot of medical and dental components. Corrosion resistance, as well as cosmetic appearance, is of the utmost importance. Without hesitation, we turn to Able to help us with our electropolishing needs. There are times when parts come back from a process, such as heat treatment, and they are darker than the customer would like. Our solution is electropolishing — the customer gets a more corrosion resistant product, and a more aesthetically pleasing one.”

— Cassandra Haupers, VP, Swiss Precision Machining Inc.
Case files — open any for the full story & photos
— The case library —

Real jobs, real parts

Every case file we have — open any for the full story and photos.

Showing 8 of 52 case files

Send us the part. Samples are free.

Attach a print, tell us the alloy and the problem, and Able’s engineering team will process free samples — typically in 24–48 hours — with a documented recommendation before you commit a lot.

Or call (888) 868-2900 · 2001 S. Kilbourn Ave, Chicago, IL 60623

Learn About the Electropolishing Difference


Electropolishing 101 Webinar

Electropolishing 101
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Learn everything you need to know about electropolishing as part of a private, interactive webinar. Let us know your availability and your part issues and our electropolishing experts can get you on our schedule.

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Try Electropolishing for Free: Sample Request

Try Electropolishing for Free:
Sample Request

Send us your parts and we’ll electropolish them for free – we’ll even pay for the shipping! Samples are processed and returned in a few days.

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Medical Device Manufacturing

Medical Device Manufacturing

From implantable devices to surgical instruments, electropolishing is a single-process treatment that results in biocompatible, safe and ultra clean parts.

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Aerospace

Aerospace

We offer aerospace vendors and original equipment manufacturers our signature metal finishing services to increase fatigue-resistance for their metal parts, rendering them capable of withstanding the stress and corrosion that comes with long-term use.

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Pharmaceutical

Pharmaceutical

Our strict adherence to industry standards ensures that pharmaceutical components are electropolished in accordance with ASTM B912 and ASME BPE specifications. These products are clean and smooth, corrosion resistant and contaminant free.

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Automotive

Automotive

Corrosion resistance and microfinish improvement are essential for critical automotive parts, making electropolishing an increasingly beneficial option for automakers.

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Consumer Appliance

Consumer Appliance

Our metal finishing services help increase corrosion resistance for these parts, and by removing the outermost layer of metal withelectropolishing the durability and longevity of these appliance components is increased.

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Food & Beverage

Food & Beverage

Electropolishing materials for this industry eliminates the buildup of bacterial biofilms, as well as keeping the equipment free of contaminants like Salmonella. Electropolishing delivers the level of sanitation required by a number of regulatory agencies.

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Hydraulics & Pneumatics

Hydraulics & Pneumatics

From robotics to mobile equipment, the uses of electropolishing in the hydraulics and pneumatics industry are many. By helping prevent premature part failure, electropolishing reduces downtime and increases the life cycle of these components.

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Electronics

Electronics

Improving conductivity and performance is just one benefit electropolishing offers for electronics parts. The surface finish is improved by as much as 50%, removing imperfections from the material without material removal.

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