Electropolishing: Improve Fatigue Life of Metal Parts

Category 04 · Improve Part Life and Performance

Fatigue Life Improvement

Electropolishing removes the surface micro-cracks where fatigue failures begin — with proven life gains up to 50%.

Extends cyclic part life
How electropolishing extends fatigue life — surface micro-cracks removed, S-N curve showing +50% cycles to failure, crack initiation and propagation sequence
Applications that benefit: valve springs, wire forms, stampings, precision tubes, machined parts
Where fatigue cracks start — 6 common origins
  • Machining & grinding — smeared metal hides micro-cracks and adds surface tensile stress
  • EDM recast — a porous, microcracked layer carrying tensile residual stress
  • Heat treating — decarburization and surface oxidation weaken the skin
  • Burrs & sharp edges — stress concentrations where cracks nucleate
  • Surface inclusions & pits — built-in initiation sites
  • Corrosion pitting in service — pits become crack starters under cyclic load
Every one of these lives in the first few thousandths of the surface — exactly the layer electropolishing removes.
Compare: recast-removal methods — pickling vs. etching vs. electropolishing
Criterion Acid pickling Chemical etching Electropolishing
Removes recast layer Partial / incidental Inconsistent Complete, incl. microcracks
Removal control Aggressive / uneven Widely varying ±.0002″, precise
Fatigue impact Neutral–negative Neutral–negative Improved
Pitting / intergranular risk High Moderate–high Low
Leaves part passivated ✗ No ✗ No ✓ Yes
Recast microcracks are fatigue initiation sites under cyclic load. Only electropolishing removes the layer and its microcracks with bounded removal while improving finish and fatigue life. Source: Able technical evaluation, EDM Recast Removal — Process Comparison.
Where it matters most
Medical implants & stentsAerospaceAutomotiveHydraulics
The full story — problem & solution
The problem

Micro-cracks and surface imperfections act as stress concentrators. On parts that cycle — springs, flexures, stents — those defects propagate into fatigue failure long before the base material reaches its limit.

How electropolishing solves it

By dissolving the imperfection layer where cracks initiate, electropolishing removes the stress risers themselves. It greatly improves the life of components that function as springs and is standard practice on Nitinol and other cyclically-loaded medical alloys.

From the field

“Phenomenal.”

— Engineer, after cycle-life testing electropolished 17-7 PH extension springs — EP was added to the spring specification
Case files — open any for the full story & photos
— AN ADDED BENEFIT —
Fatigue life isn’t the only thing the pass buys you.

Springs, wire forms and shafts usually need passivation anyway — and the surface that resists crack initiation is the same surface that resists corrosion pitting, which becomes an initiation site of its own under cyclic load. One operation covers the crack origins, the passive layer, and the finish.

Corrosion Resistance →Microfinish Improvement →

Deburr→Clean→Passivate→1 pass
electropolishing
3-in-1Deburred, defect-free and passivated in one pass.

Electropolishing can eliminate the separate deburr, clean and passivation steps a part would otherwise need — outperforming passivation and pickling across the board.

● Fewer handling steps   ● Shorter lead time   ● Lower cost per part
— 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
Webinar

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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