ASTM methods

Why it matters

A number like "yield strength 350 MPa" means little without the method behind it. Specimen shape, gauge length, test speed, temperature, conditioning and how each property is calculated all change the result. Standard test methods fix those choices so that a lab in Ohio and a lab in Osaka get comparable numbers, customers can write specifications, and auditors can check your work. Materials scientists read, follow and cite standards every week.

Who writes standards

• ASTM International (https://www.astm.org) publishes over 12,000 standards written by volunteer committees of producers, users and academics. Metals testing lives mostly in committee E28, plastics in D20.
• ISO (https://www.iso.org) publishes international standards, adopted nationally (for example as EN ISO in Europe).
• Industry and government bodies add their own: SAE/AMS for aerospace materials, ASME for pressure equipment, military specifications, and customer specifications that call up ASTM or ISO methods.

Standards are copyrighted and most are sold, not free. Many universities and employers subscribe; check your library before buying. ASTM's site shows each standard's title, scope and summary free, which is often enough to choose the right one. Checked on 2026-10-23.

Reading a designation

Take ASTM E8/E8M-24, the tension test for metals:

• E is the category (miscellaneous subjects, which includes most metals test methods); D is used for plastics and many other materials.
• 8 is the number.
• /E8M means the standard covers both inch-pound and SI units in one document.
• -24 is the year of the last revision. A trailing year in parentheses, like (2019), means it was reapproved without changes; a superscript epsilon marks an editorial change.

Always record the exact edition you used. Contracts and specifications often call up a specific year.

Common methods in a materials lab

Use this list only to know where to look. The documents themselves define the details.

The structure of a test method

Most ASTM methods follow the same outline, so once you have read one you can navigate any of them:

1. Scope: what materials and conditions the method covers, and what it does not.
2. Referenced documents: other standards you also need (for example, E4 for force verification of the machine, E83 for extensometers).
3. Terminology, summary and significance and use.
4. Apparatus: required equipment and its calibration.
5. Test specimens: dimensions, tolerances, how to take them from the product.
6. Procedure: speeds, temperatures, conditioning, the exact sequence.
7. Calculation of each property.
8. Report: the information you must include.
9. Precision and bias: how much results vary within and between labs.

The report section is your checklist. The precision and bias section tells you whether a difference between two results is real or within normal lab scatter.

Following a method in practice

• Work from the current controlled copy your lab holds, not an old PDF.
• Many labs write a short work instruction that applies the standard to their own machines. The standard wins when they conflict, unless the customer specification says otherwise.
• Any deviation (a different specimen size, a missed conditioning time) must be recorded in the report, not quietly absorbed.
• Calibration matters: load cells, extensometers and thermocouples are verified to their own standards at set intervals.
• Accredited labs work to ISO/IEC 17025, which audits exactly this: methods, calibration, records and competence.

Common mistakes

• Citing a standard without the year, or using a superseded edition.
• Using the wrong specimen geometry and comparing results with data from another geometry.
• Skipping conditioning for plastics, whose properties depend on temperature and humidity.
• Reporting fewer specimens than the method requires, or leaving out failed tests without a stated reason.

Safety and training

Running tests means operating machines, furnaces and chemicals covered by your lab's procedures. Follow your institution's training and supervision before running any method for real. The activity below is a paper exercise.

Recap

• Standards fix the choices that change results; always cite designation and year.
• ASTM and ISO methods share a structure: scope, apparatus, specimens, procedure, calculation, report, precision.
• Record deviations, keep calibrations current, and use the report section as your checklist.

Try it

Open the Do tab to find a method on the ASTM website and draft a test plan and report outline that follow it.