• ByRouging Solutions Editorial Team  ·  19 August 2026

Medical Device Surface Finishing: ASTM F86 Compliance Explained

ASTM F86 for medical devices covers the surface preparation and marking of metallic surgical implants. The passivation itself is normally specified to ASTM A967, the same spec the rest of the industry uses. That is why implant work and pharma equipment work share so much chemistry.

What changed this year is the regulatory frame around that work. FDA's Quality Management System Regulation took effect on 2 February 2026, and it rebuilt 21 CFR Part 820 around ISO 13485. If your surface finishing records were written to the old clause numbers, they now reference a structure that no longer exists.

What Does ASTM F86 Actually Cover?

ASTM F86 is the practice the medical device industry uses for preparing and marking implant surfaces. It sits across alloys, so titanium and 316L stainless implants are both in scope. It sets out the condition a finished surface should be in before it reaches a patient.

For stainless steel, the passivation is normally specified to ASTM A967. That spec defines the chemical treatments and the tests used to accept them. Our guide to ASTM A967 walks through those treatment types and acceptance tests in detail.

ASTM standards are sold, so this article describes what they govern without reproducing the text. Buy the current edition before writing a procedure against it, and check the revision year, because acceptance criteria move between editions.

Why Does Surface Condition Matter on an Implant?

Because free iron on a stainless surface is where corrosion starts, and an implant has no maintenance window.

Machining, grinding and forming embed iron particles into a stainless surface, and so does handling the part with carbon steel tooling. Those particles sit on top of the chromium oxide film. In a chloride-bearing environment, and body fluid qualifies, they start pitting.

Passivation removes that surface iron and lets the chromium oxide layer re-form evenly. It is a cleaning step with a metal purpose, and it decides whether a part stays passive or corrodes at a scratch.

We work through this across implant, instrument and equipment manufacturing on our medical industry page, on site or at our own premises.

What Changed in FDA's Rules on 2 February 2026?

Part 820 was rebuilt. FDA changed the device current good manufacturing practice (CGMP) rules to line up with the global standard. The revised part is now called the Quality Management System Regulation.

The final rule states that it is "effective February 2, 2026". FDA says it is harmonizing "primarily through incorporating by reference the quality management system requirements of ISO 13485" (Federal Register, 89 FR 7523).

The practical consequence catches people out. Part 820 holds six sections (21 CFR Part 820). They are scope, definitions, incorporation by reference, the quality system rule, control of records, and labeling and packaging controls. The detailed CGMP clauses that procedures used to cite are no longer there.

So a work instruction citing an old clause number now points at nothing. The obligation did not disappear. It moved into ISO 13485, which the revised Part 820 incorporates by reference.

What Does the QMSR Expect From a Surface Process?

A documented system, and evidence that the process does what you say it does.

Section 820.10 requires a manufacturer to "Document a quality management system that complies with the applicable requirements of ISO 13485". On a surface finishing line it reaches every step. The method, the chemistry, the concentration, the temperature, the contact time and the acceptance test all have to be specified and recorded.

For Indian manufacturers exporting to the United States, one line in the regulation deserves attention. A device offered for import "is subject to refusal of admission" if it appears adulterated under the Act. So a quality system failure on a surface process becomes a border problem.

Our passivation service is delivered against a written procedure and a record set for exactly this reason. We reply within 24 hours.

What Do Indian Manufacturers Answer To at Home?

CDSCO, the Central Drugs Standard Control Organisation, under the Medical Devices Rules, 2017, which asks for the same kind of evidence.

The Fifth Schedule carries the quality management system requirement, and a Notified Body audits the manufacturing site by "examination of objective evidence" (Medical Devices Rules, 2017). Devices sold into Europe add EU MDR as well.

Which authority you deal with depends on the risk class. Class A and Class B devices are licensed by the State Licensing Authority, with a Notified Body carrying out the site audit. Class C and Class D sit with the Central Licensing Authority.

So a surface process can face three regimes at once, and they share one habit. Each wants to see that the treatment was specified, carried out and recorded. A passivation record is exactly the kind of objective evidence all three look for.

Which Passivation Route Suits Implant Alloys?

Citric acid handles most implant stainless work, and it does so without the hazards nitric brings.

NASA's own testing supports the substitution. Its work on citric acid passivation of stainless steel documents the process and the control plan behind it (NASA NTRS). A later NASA and DoD study tested citric against nitric on stainless alloys and concluded that the citric process "performs as well as, or better than, the nitric acid passivation process according to the testing employed" (NASA NTRS).

That study also found process parameters mattered. Corrosion performance for one alloy improved as bath temperature rose, so the optimum conditions were set per alloy. That dependence is the point worth carrying into implant work. A treatment proven on 316L is not automatically valid on 17-4 PH or a cobalt chrome part. Run the acceptance test on the alloy you actually ship.

Our comparison of citric and nitric acid passivation sets out the trade-offs. Waste handling is one of them, and it weighs more in a small shop.

How Do You Prove the Surface Is Clean?

With a test that produces a record. Run it on the finished part, because a coupon nobody kept proves nothing about what shipped.

Choose the test your spec calls for, and keep the record with the lot. Our inspection and monitoring work exists to produce that evidence in a form an auditor accepts.

What About Marking and Traceability?

ASTM F86 addresses marking as well as surface preparation, and the two interact more than people expect.

A mark applied by an aggressive method can disturb the passive layer at exactly the point where the metal has been worked hardest. Laser marking, electrochemical etching and stamping each leave a different surface behind. The sequence matters. Mark first, then passivate, so the final treatment covers the marked area.

Depth matters too. A deep stamp raises a burr and work-hardens the metal round it. Both give corrosion somewhere to start, and neither is fixed by passivation afterward.

Where a fine finish is needed before marking, our mechanical and electropolishing work sets it up.

What Records Should the Lot File Hold?

Enough for a stranger to rebuild the run without asking you a question.

Six items cover most audits, and an auditor who finds all six stops looking:

1. The written procedure, with its revision number and date.
2. The chemical used, its batch number, and the supplier certificate.
3. Bath conditions: concentration, temperature and contact time, as measured.
4. The rinse step, including water quality, because a poor rinse undoes the treatment.
5. The acceptance test, naming the method, the part tested and the result.
6. The operator and the date, so the record ties to a person and a shift.

Keep these with the lot. A separate binder on another floor defeats the point, because an auditor who has to hunt for a rinse record will assume it was written later.

One habit saves argument. Photograph the test result and file it with the number, because a written "pass" carries less weight than an image of the part.

Where Indian Manufacturers Get Caught

Five patterns account for most of the surface-related findings we are asked to investigate.

The first is a procedure written against superseded clause numbers, which now reads as though it references nothing. The second is passivation validated on one alloy and applied to a family. The third is a test run once at qualification and never repeated at release.

Fourth is carbon steel tooling used on stainless in the same shop, which quietly puts back the contamination the treatment just removed, and it is the hardest of the five to spot, because nothing looks different until it corrodes in service. Fifth is a record that proves the chemical was used but not that the surface passed, which is the version an auditor rejects.

Our post on common passivation failures covers the mechanisms behind several of these.

A Fictional Example of a Rejected Lot

The following scenario is fictional, and the numbers in it are illustrative, with no client data involved.

An implant shop near Ahmedabad passivates a lot of 316L bone screws using a settled citric process, then laser-marks them to fix a readability complaint. The ferroxyl test at release is run on a screw pulled from the lot before marking, and it passes.

Three months later, a customer audit asks how the marked surface was verified. There is no answer, because the marking happened after the last surface test. The lot is quarantined. The screws did not corrode, but the record cannot show the marked area was passive.

The fix costs a day. Mark before the final treatment, take the release sample from a marked part, and the lot ships on time with a record nobody can argue with.

If your surface procedures still cite the pre-2026 clause numbers, or you are qualifying a passivation route on a new implant alloy, talk to our team. Bring the procedure and the last release record, because those two documents usually show where the gap is.

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