ASTM, EN, DIN, ASME: how they relate to ГОСТ
There are several standards for stainless steel, and they answer different questions. AISI gives a grade its number and describes the composition, ASTM sets requirements for products, EN and DIN operate in Europe, ASME in boiler supervision and pressure equipment, and ГОСТ in Russia and the EAEU.
The phrase "AISI 304 according to which standard" is incorrect in itself: AISI 304 is a grade, and the delivery standard is chosen separately, for example ASTM A240 for sheet.
Below — who invented these systems, a comparison table, what to write in the contract and how to verify certificates on acceptance.
Who invented the standards
AISI — American Iron and Steel Institute. The institute introduced the grade numbering system for stainless steel: 201, 304, 316, 430 and so on. This is a designation system for compositions, not a delivery standard for rolled steel.
ASTM — American Society for Testing and Materials. It develops standards for products, test methods and materials. For stainless steel the key documents are for sheet and strip (A240) and for pipes (A312 for seamless and welded austenitic pipes). ASTM covers both dimensional tolerances and acceptance requirements.
EN — European norms that replaced national standards. The designation is double: a material number such as 1.4301 and a product standard such as EN 10088.
DIN — the German Institute for Standardization. Some DIN standards are still in force, especially for finished products: for example, DIN 975 for threaded rod and DIN 11850 for pipes for the food industry.
ASME — American Society of Mechanical Engineers. For stainless steel it matters because it sets requirements for pressure equipment and vessels. ASME standards often refer to ASTM but impose additional requirements on materials and inspection.
ГОСТ — the Russian system. The composition is embedded right in the grade: 12Х18Н10Т reads as 0.12% carbon, 18% chromium, 10% nickel, titanium. The product range and acceptance are covered by separate standards for each type of rolled product.
| System | What it sets | Example designation |
|---|---|---|
| AISI | grade and composition | AISI 304, AISI 316L |
| ASTM | products, tolerances, acceptance | ASTM A240, A312 |
| EN | composition and products | 1.4301, EN 10088-2 |
| DIN | finished products, old designations | DIN 975, 1.4301 |
| ASME | pressure equipment | ASME materials |
| ГОСТ | grades, product range, acceptance | 12Х18Н10Т, ГОСТ 5632 |
Comparison table
A grade match and a standard match are different things. The table below lists grades, not documents: it shows that 304, 1.4301 and 08Х18Н10 describe a similar composition.
| AISI | EN | ГОСТ | ASTM (example) | Key difference |
|---|---|---|---|---|
| 201 | 1.4372 | 12Х15Г9НД | A240 | manganese instead of part of the nickel |
| 304 | 1.4301 | 08Х18Н10 | A240, A312 | base austenitic grade |
| 304L | 1.4307 | 03Х18Н11 | A240, A312 | low carbon |
| 316 | 1.4401 | 10Х17Н13М2 | A240, A312 | molybdenum, resistance to chlorides |
| 316L | 1.4404 | 03Х17Н14М2 | A240, A312 | molybdenum plus low carbon |
| 316Ti | 1.4571 | 10Х17Н13М2Т | A240 | molybdenum plus titanium |
| 321 | 1.4541 | 12Х18Н10Т | A240, A312 | titanium, heat resistance |
| 430 | 1.4016 | 12Х17 | A240 | ferritic, no nickel |
| 310S | 1.4845 | 20Х23Н18 | A240 | high heat resistance |
| 904L | 1.4539 | 06ХН28МДТ | B625 | copper and molybdenum |
How to use this. A grade match describes a similarity of composition, not full interchangeability. When you substitute a grade, the dimensional tolerances and acceptance rules change, so in a critical assembly verify the requirements.
A note on DIN 11850. This is a standard for pipes for the food industry, and it sets not only the composition but also the geometry and the surface quality. So the entry "AISI 304 DIN 11850" is a grade plus a specific product standard, not a synonym for 304.
What to write in the contract
The contract must be unambiguous. An error in one line of the specification costs more than it seems: reissued documents, downtime, a returned batch.
The minimum set in an order or specification:
- Grade — 08Х18Н10, AISI 304, 1.4301. Specify one system, not a mixture.
- Product standard — ГОСТ for sheet or pipe, ASTM A240, EN 10088-2.
- Grade standard — ГОСТ 5632 or ASTM A240, if it does not follow from the product standard.
- Type of rolled product and size — sheet 2×1250×2500, pipe ⌀38×1.5, round bar ⌀20.
- Delivery condition — cold-rolled, hot-rolled, calibrated, heat-treated.
- Surface — 2B, BA, mirror, №4 ground.
- Tests — which ones are needed, if the standard allows a choice.
- Form of documents — quality certificate per batch, language, and a notarised translation if necessary.
| What to specify | Bad | Good |
|---|---|---|
| Grade | "stainless steel" | AISI 316L |
| Standard | "to ГОСТ" | ГОСТ 9941, grade 03Х17Н14М2 |
| Size | "thin pipe" | ⌀38×1.5×6000 |
| Surface | "ordinary" | ground |
| Accuracy | not specified | increased |
Certificates and acceptance
A certificate is the document that links the batch to the requirements of the standard. If a batch runs under two systems, the certificate will reference both, and it must be read line by line.
Verification procedure:
- Write out from the specification the grade, standard, size, accuracy, surface and delivery condition.
- Find the references to standards in the certificate. If it names a document that is not in the specification, that is a reason to ask a question.
- Check the composition. The mass fractions of the elements must fall within the grade limits of the standard specified.
- Check the mechanical properties and the test results.
- Check the dimensions by measuring: the tolerances come from the agreed product standard, not from a convenient document.
- Check the scope of application. A document for sheet does not confirm a pipe.
A common mistake is to assume that an ASTM certificate automatically covers ГОСТ requirements, or vice versa. These are two different sets of requirements, and they do not fully coincide. The second mistake is to accept an imported pipe against a certificate for sheet: the grade matches, but the product standard is different.
What is important to remember about substitutions. If the specification says 12Х18Н10Т and AISI 321 arrives, the composition is close, but formally it is a different grade. For non-critical structures the substitution is usually acceptable; for pressure equipment it is not.
Frequently asked questions
What is the difference between AISI and ASTM?
AISI is a grade designation system; it describes composition. ASTM is an organisation that issues standards for products, tolerances and tests. So "AISI 304" says what the steel is made of, and "ASTM A240" says by what rules the sheet was made and accepted.
Which standard does AISI 304 follow?
For sheet and strip it is most often ASTM A240, for pipes — ASTM A312. In Europe the equivalent is EN 10088-2 with material number 1.4301. In Russia a close composition is 08Х18Н10, and the standard for the rolled product is chosen by type of product.
What does AISI 304 (DIN 1.4301) mean?
It is the same grade in two designation systems: American and German. The notation is convenient for correspondence with European suppliers, but for a delivery you need to add the product standard — sheet, pipe or round bar.
How does DIN 975 differ from DIN 11850?
DIN 975 is the standard for threaded rod, DIN 11850 for pipes for the food industry. Both belong to the German system, but they describe different products. The grade in them may be the same, while the requirements for geometry and surface differ.
Is ASME mandatory if there is ASTM?
No. ASME is applied to pressure equipment and vessels: it refers to ASTM and adds its own requirements for materials and inspection. If a product does not fall under ASME, ASTM or EN is enough.
Can 12Х18Н10Т be replaced by AISI 321?
The composition is close, so for non-critical structures the substitution is usually acceptable. But formally it is a different grade and a different standard. For critical assemblies and aggressive media, verify the requirements of the standard and the batch certificate.
What should I do if the certificate is in another language?
Request a translation of the relevant fields: grade, standard, batch number, composition, mechanical properties, dimensions. For acceptance it is important to understand what exactly the document confirms. If the contract stipulates the language of the documents, the supplier is obliged to comply.
Place an order with a clear standard
On the GCX exchange an order fixes the grade, type of rolled product, size, surface and shipment week — the characteristics are carried into the trade without renegotiation. AISI 201, 304, 316L and 430 are traded.