ASTM F136 Titanium: What It Means and How to Verify It

What F136 fixes, how to read a 3.1 report, and a worked example built on real certificates.

The Tremun Team

Two bars of titanium can look identical and polish to the same colour. One is ASTM F136. The other is industrial Grade 5. Only a document tells them apart. This guide shows what the standard fixes, how to read that document, and when to refuse it.

We are a titanium supplier, so the worked example uses our own published documents. A mill report describes the bar. A lab test on finished pieces checks the jewellery. We publish both, so you can apply every check in this guide to us first.

For metal comparisons, read Titanium is better than steel und Why titanium is the best material for piercing jewellery.

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Is F136 implant grade titanium good for piercings?

Yes, with conditions. ASTM F136 is one of the titanium standards in the APP minimum standard for initial jewellery. But the letters “F136” on a website prove nothing alone. The claim is only as good as the certificate behind it.

Design, polish and threads come later, in the workshop. A good certificate cannot rescue a poor finish. A good finish cannot replace a missing certificate.

What is ASTM F136? What the standard specifies

ASTM F136 is a material specification for Ti-6Al-4V ELI bar and wire for surgical implants. Its alloy code is UNS R56401, and the trade often calls it “Grade 23”. The standard fixes the chemistry, the minimum strength and the annealed structure of the metal.

Read the oxygen line first

Oxygen is the main difference between F136 and ordinary Ti-6Al-4V, sold as Grade 5. F136 allows a maximum of 0.13% oxygen. Grade 5 allows up to 0.20%, and so does ISO 5832-3. Only the certificate shows which limit your metal meets.

Chemistry in weight per cent. Hydrogen may reach 0.015% in very thin material (0.813 mm or less). Mechanical minimums for annealed bar and wire in jewellery sizes, such as 4 mm bar.

Editions: what the year means

The year after the number is the edition, such as F136-13 or F136-26. F136-26 has been the active edition since February 2026. A mill report cites the edition in force when the bar was made, so older editions remain common. Check that an edition is named, and note it in your records.

F136 vs G23, Grade 5 and ISO 5832-3

“Implant grade” is not a standard at all. It only counts when a named specification follows it.

Decision rules from this table:

• F136 named: accept, then check the values against the F136 limits above.
• ISO 5832-3 named: accept, then check the values against ISO 5832-3 limits. ISO 5832-3 is not ELI. It allows oxygen up to 0.20% and iron up to 0.30%. F136 limits are tighter for oxygen, iron and yield strength.
• Only “Grade 23” or “G23”: not enough. ASTM B348 Grade 23 is the same alloy family under an industrial bar specification, with slightly different limits. It has no implant requirements and a different alloy code, UNS R56407. Request the implant standard.
• “Grade 5” or “Ti-6Al-4V” with no implant standard: reject for initial piercings. ASTM B348 Grade 5 is an industrial bar specification, and APP does not list it.

One report can name several standards at once. A single bar can meet F136, ISO 5832-3 and B348 Grade 23 together. That is normal, and you will see it in our own reports below. What matters is that an implant standard is on the list.

Why EN 10204 3.1, not 2.2

The chain. Each melt of titanium gets a heat number. That melt becomes bar lots, and a bar lot becomes jewellery batches. The heat number links the paper to the metal. Without it, a certificate is only a general statement.

The test report for that melt is an inspection document, often called a mill certificate. The European standard EN 10204 defines four types.

In short, request a 3.1 report with a heat number. A 2.2 only describes the product type, not your metal.

Three layers of proof: ingot, bar, finished piece

Proof can exist at three points between the melt and the polished piece. The ingot is the large block the mill melts first. It is then worked down into bar, and the bar is machined into jewellery.

The bar report is the minimum you should accept. The ingot and finished-piece layers add depth.

How to read a 3.1 certificate, point by point

Read every 3.1 report in the same order. The figure below shows where each point usually sits on the page. Each legend item tells you what to look for and what to do.

Anatomy of a 3.1 certificate

The 10 points to check

1. 1Certificate issuer: check the producing mill’s name and letterhead. A reseller may add a cover page, but the mill’s own report must follow.
2. 2Document type: find “EN 10204 3.1”, printed clearly. A 2.1 or 2.2 is not enough.
3. 3Spezifikationen: confirm a named implant standard with its edition year, such as ASTM F136-13. ISO 5832-3 or B348 Grade 23 may appear as well.
4. 4Heat number: match it on every page. It must be present, readable and identical each time.
5. 5Product form and size: check the bar or wire diameter fits your pieces, such as 1.6 mm or 4.00 mm. Codes such as h7 describe how exact the diameter is.
6. 6Condition and melting route: look for “annealed”. The melting method is often listed too.
7. 7Chemical analysis: compare each measured value with the limits of the named standard. Values often come from the top and bottom of the ingot.
8. 8Mechanical results: check tensile strength, yield strength and elongation against the minimums (F136: 860 MPa, 795 MPa, 10%). Each value needs its unit.
9. 9Metallurgy: look for an alpha-beta structure, and a statement such as “free of alpha case” or “no continuous alpha case”.
10. 10Signature and date: confirm a signature or stamp of the inspection representative, and a date.

How to read the numbers. Compare each value with the limit of the named standard. Read the value as printed, and do not round it yourself. Certificates may print decimals with a point or a comma. Values near a limit are explained below, with our own numbers.

Alpha case is a hard, brittle, oxygen-rich surface layer. “Free of alpha case” is the statement you want.

Other lines you may see

Mill reports often carry extra lines. They are not required by F136, but they tell you how carefully the bar was checked.

• Eddy-current test: an electrical test that finds cracks and flaws at or just below the bar surface, without touching it.
• 100% visual inspection: every bar was looked at, not only a sample.
• Annealing temperature and time: for example, 788 °C for 1 hour.
• “Cannot be reproduced except in full”: the mill wants you to read the whole report, never a single page.
• “Free of mercury and radioactive contamination”: a standard statement about the material.

Tremun’s certificates, opened line by line

Our Zertifikatsseite publishes the documents below. One document shows a packing list with eight heats of bar. Full mill reports are published for the four 1.6 mm heats, from 2014 to 2018. The 2026 heat, 30553DG, has its own declaration with the full mill report attached. Two independent lab tests on finished pieces complete the set.

You can read the original reports in full, with their issuers, on our certificates page. The table gives the key values from each report, copied as printed. Where a report gives top and bottom values, we show a range.

What the table shows

Every value sits inside F136. That holds for all seven sets of results, across two bar sizes.

• Oxygen: 0.05% to 0.13%. The F136 maximum is 0.13%.
• Iron: 0.077% to 0.17%. The maximum is 0.25%.
• Aluminium and vanadium: 5.50% to 6.41%, and 3.55% to 4.06%. Both stay inside their ranges.
• Carbon, nitrogen and hydrogen: carbon 0.009% to 0.028%, nitrogen below 0.016%, hydrogen 0.0009% to 0.006%. All are far below their limits. The full values are in the reports.
• Tensile strength: 1001 to 1062 MPa. The minimum is 860 MPa.
• Yield strength: 888 to 924 MPa. The minimum is 795 MPa.
• Elongation: 11% to 22%. The minimum is 10%.

The values also vary from heat to heat, as real measurements do.

Values near a limit. A limit is a pass line. A value exactly on the line conforms, and a value beyond it does not. Two of our values sit on a line. Aluminium is 5.50% in the 2025 lab test, the lower end of 5.50–6.50%. Oxygen is 0.13% at the top of the 2026 ingot, and 0.12% at the bottom. Both conform.

Every lab result also carries some measurement uncertainty. So do not adjust a printed value up or down yourself. For a lab test, the lab’s own conformity statement is what counts. Both of our lab reports state that the chemistry conforms to ASTM F136.

What else the reports record

The four older mill reports cover 1.6 mm bar, and the 2026 report covers 4.00 mm bar. Diameters carry tolerance codes: h7 on the 2016–2018 bar and h8 on the 4.00 mm bar.

The four 1.6 mm mill reports are signed and dated by the mill. The 2026 declaration attaches its mill report in full. Each mill report includes the ingot chemistry from top and bottom. The reports for heats 8V37036, PVD3696, PVD4439, PVD5351 and 30553DG state that the bar is free of alpha case. Several also record eddy-current testing.

The editions follow the rule above. The 2014 report cites ASTM F136-13 and ISO 5832-3 (1996). The 2016–2018 reports add ASTM B348 Grade 23. The 2026 documents cite ASTM F136-13 (R2021), B348 Grade 23 and ISO 5832-3:2021. Heat 30553DG was melted in March 2024, before F136-26 became active. So a 2026 declaration that cites the 2013 edition is what the edition rule predicts. The 2016 report also names a French and a British implant standard, NF S94-080-1 and BS 7252-3.

The 2026 report also lists a surface roughness of Ra ≤0.8 µm. That value describes the bar as delivered, before any polishing. It says nothing about the finish of a piece. Your loupe check covers that.

What an independent test of finished jewellery adds, and what it cannot prove

A mill report describes the bar. A finished-piece test checks the jewellery after every step in the workshop.

We sent finished jewellery to an independent laboratory twice, in 2023 and in 2025. The samples were finished posts, barbells and rings, not bar. The lab measured metals with an ICP-OES spectrometer, a standard instrument for metal analysis. Other instruments measured carbon, oxygen, nitrogen and hydrogen, partly at a partner laboratory. Both reports state that the chemistry conforms to Ti-6Al-4V under ASTM F136.

How to judge any finished-piece test. Check five things. The sample must be finished jewellery, not bar. The report must name the standard it checks against. It needs measured values, not only “conforms”. It needs a date and a signature. And it must be the complete report, with all its pages.

Traceability you can see

Documents only help if they connect to the metal. Here is how that link looks in our published documents.

The packing list. One box of Ti-6Al-4V ELI bar is listed by diameter and heat number. It holds eight heats in four diameters, from 1.6 mm to 4 mm.

The tagged bundles. Photos show the bar bundles with hand-written tags. Each tag gives the diameter, heat number, length and weight. For the four 1.6 mm heats, the same heat number then appears on the published mill report.

Then keep your own record. For each delivery, note the date, supplier, product and the documents you received. A simple spreadsheet is enough. If a client or an inspector raises a question, you can answer with a document.

Warning signs: when to refuse a certificate

Each sign below means the document cannot show what it should. None of them proves fraud on its own.

• No heat number, or different numbers on different pages.
• No named specification. Only “titanium”, “G23” or “implant grade”.
• The wrong specification. B348 bar presented as F136 material.
• The wrong document. A 2.1 or 2.2, or a simple “certificate of conformity”.
• No validation. No signature, stamp or date.
• An altered copy with no original. Re-typed lines, changing fonts, cropped or blurred pages.
• No measured values. Only “conforms” or “pass”, or numbers without units.
• Values copied from the standard. Every element matches the printed maximum or minimum.
• One old document for everything. The same undated report for every size and every year.

One warning sign is enough to pause the order. With two or more, send your questions before any further order.

Questions to send a supplier

Question 6 matters for chains and coated pieces. Only the titanium part can be F136. Any other metal or coating needs its own documentation.

Expect written answers before you place an order.

What we publish. Here is how Tremun answers all ten questions.

• Question 1: our titanium is ASTM F-136 (Ti-6Al-4V ELI), sourced in France.
• Question 2: we publish five complete mill reports, with all their pages and the ingot chemistry.
• Question 3: yes. Our certificates page is open before you register.
• Question 4: our certificates cover our titanium stock, not individual orders. Today we cannot tell you which heat covers a specific order. Ask us and we will send any report on that page as a complete PDF.
• Question 5: every titanium product page names the standard: ASTM F-136.
• Question 6: product pages declare any other material. Chains with niobium links and pieces with a PVD coating state it.
• Question 7: product pages name the finish where one is stated, such as “Mirror polish”.
• Question 8: product pages state the thread type and “Autoclave safe”.
• Question 9: a lifetime warranty covers every piece.
• Question 10: yes, from 2023 and 2025.

The 60-second check before you order

What the certificate does not cover: surface and finish

Die APP minimum standard for initial jewellery makes this point itself. A certificate shows the grade of the material, not the origin of each piece. APP also advises buying from a reputable supplier.

The certificate also stops at the bar. Even a lab test on finished pieces checks chemistry, not finish. APP expects a mirror polish on every surface that touches tissue. Look for no tool marks, sharp edges or leftover polishing paste. Posts should be internally threaded or threadless.

Check a few pieces from each new delivery, not only the first order. Write the result in your supplier record, next to the delivery date.

Where F136 meets APP standards and EU rules

France. The Public Health Code (article R1311-4) requires anything that goes through the skin to be sterile or sterilised before use. Initial jewellery is included. A ministerial order of 3 December 2008 requires studios to inform clients about risks, including allergy to jewellery metals. These rules do not name an alloy.

APP. The Association of Professional Piercers is an international non-profit association based in the United States. For initial jewellery, it accepts titanium to ASTM F136, ASTM F1295, ISO 5832-3 or ASTM F67.

REACH nickel rule. REACH Annex XVII, entry 27 covers posts inserted into pierced parts of the body. They must release less than 0.2 µg/cm² of nickel per week. The reference test is EN 1811. The rule measures release from the finished product, not the alloy name.

General Product Safety Regulation. Regulation (EU) 2023/988 applies since 13 December 2024. Each product needs a type, batch or serial number, plus the manufacturer’s contact details. Imported products also need the importer’s details. Check that each delivery carries this information before you sell or fit the pieces.

Every EU country. REACH and the GPSR apply in all EU member states, including Spain and France.

Legal status. “Implant grade” describes the bar standard, not the legal status of the piece. F136 is a professional standard, not a legal requirement.

How to explain F136 to a client

Clients often want absolute promises: no nickel at all, and no reaction ever. Avoid both.

Avoid absolute health promises, and any approval or medical label the piece does not hold. Promise only facts you can show.

Demand the documents

Demand a named specification and a signed 3.1 report for each heat. Prefer a supplier who shows both openly, before you register. Then check the finish yourself, with a loupe, on every delivery.

FAQ