Standards cross-reference
Fastener Standards Cross-Reference: DIN, ISO, ANSI/ASME and BS Designations
Drawings mix legacy DIN designations, current ISO documents and inch-series ANSI/ASME callouts. These tables line the designations up by product family — and state, row by row, where a mapping is only an approximation and where our collected sources simply do not state one. Nothing here should be read as a blanket statement that two standards are interchangeable.
How to read these tables
Each row shows the legacy DIN designation buyers still order by, the current ISO / DIN EN ISO document, and the inch-series counterpart where one exists. A designation mapping answers a sourcing question — what document does this part belong to — not a substitution question. Two visually similar fasteners made to different standards can differ in width across flats, head height, under-head geometry and thread tolerance even at the same nominal size, so always order the designation your drawing calls out. Cells marked Confirm at quotation or Not stated in our sources are exactly that: our collected sources do not establish the mapping, and we will not fill it in. Send us the designation and we will confirm against the applicable standard edition and tolerance class.
For the full argument on why equal-looking callouts are not equal, read DIN, ISO, ANSI/ASME and JIS fasteners: can you treat them as interchangeable?
Hex bolts and structural bolts
The hex bolt is the clearest case of "same part, several designations": DIN 933 (fully threaded) and DIN 931 (partially threaded) live on as ordering shorthand while ISO 4014/4017 are the current documents, and the inch series runs on ANSI/ASME B18.2.1 with ASTM material standards stacked on top. Property classes (ISO 898-1) and SAE grades are separate scales — see the qualification notes.
| Product | DIN (legacy) | ISO / current | ANSI / ASME / inch series | BS | What this mapping means | On this site |
|---|---|---|---|---|---|---|
| Hex bolt, metric, fully threaded | DIN 933 (legacy designation, still the most-ordered shorthand) | ISO 4017 (partially threaded: ISO 4014) | ANSI/ASME B18.2.1 hex cap screw (inch dimensions) | Confirm at quotation | Designation lineage, not automatic interchange: visually similar hex bolts to different standards can differ in width across flats, head height, under-head geometry and thread tolerance even at the same nominal size. Order the designation your drawing calls out. | |
| Property class 8.8 bolt (mechanical property) | DIN 933 / DIN 931 delivered in class 8.8 | ISO 898-1 Class 8.8 — 800 MPa min tensile (830 above M16), 640 MPa yield | Approximate shorthand: SAE J429 Grade 5 — NOT an exact equivalent | Confirm at quotation | Class 8.8 (≈116,000 psi) sits between SAE Grade 5 (120,000 psi) and Grade 8 (150,000 psi). The "8.8 ≈ Grade 5" shorthand is approximate because test methods and proof-load definitions differ. Never substitute on a drawing that names a specific standard. | |
| Property class 10.9 / 12.9 bolts (mechanical property) | Class 10.9 / 12.9 delivered under DIN designations | ISO 898-1 — 10.9: 1,040 MPa min tensile, 32–39 HRC; 12.9: 1,220 MPa, 39–44 HRC | Approximate region: SAE Grade 8 (150,000 psi); no source establishes an exact pair | Confirm at quotation | Higher hardness brings higher hydrogen-embrittlement exposure — susceptibility rises significantly above 39 HRC (380 HV), and class 12.9 carries an ISO 898-1 stress-corrosion caution. Strength-matched does not mean application-equivalent. | |
| Heavy hex structural bolt | Not a DIN product family — structural bolting is inch-series in US practice | High-strength metric structural bolting is specified per ISO 898-1 classes with the joint design standard governing | ASTM F3125 Grades A325 and A490 (F3125 supersedes the former A325/A490 spec designations); TC bolts per F1852 | Confirm at quotation | SAE J429 Grade 8 and ASTM A490 have similar strength levels but are manufactured to different standards and are generally not interchangeable in structural steel applications without engineering approval. | |
| Flange bolt, metric | DIN 6921 | Ordered under the DIN 6921 designation; confirm the current ISO designation at quotation | Inch-series hex flange screws run under IFI/ASME patterns — confirm the exact callout | Confirm at quotation | The integrated flange replaces a separate washer; serrated and non-serrated variants behave differently on painted or soft surfaces. |
Socket screws and set screws
Socket head cap screws are the cleanest DIN→ISO transition in the catalogue: the product did not change, the document did.
| Product | DIN (legacy) | ISO / current | ANSI / ASME / inch series | BS | What this mapping means | On this site |
|---|---|---|---|---|---|---|
| Socket head cap screw, metric | DIN 912 (superseded designation) | DIN EN ISO 4762 — the current document; order whichever designation your drawing calls out | Inch-series socket cap screws run under ASME B18.3 — confirm the exact callout at quotation | Confirm at quotation | Our sourcing treats DIN 912 as the equivalent national designation of ISO 4762: dimensions are taken "according to ISO 4762". Drawings that name one designation should keep it. | |
| Socket set screw, metric | DIN 913 (flat point) within the DIN 900-series set screw family | Confirm the current ISO designation for your point style at quotation | Confirm at quotation | Confirm at quotation | Point style (flat, cone, cup, dog) is part of the designation — the callout is incomplete without it. | |
| Structural bearing bolts (EU practice) | Not applicable | BS EN 15048 (non-preloaded structural bolting) named in our collected screw standards | Not applicable | BS EN 15048 — the designation our sources state | Preloaded connections use a different part of the standard family — confirm which connection class your joint uses. |
Nuts: hex, lock and flange
Nut standards split into geometry (which pattern) and material grade (which strength). The inch series fixes geometry in ASME B18.2.2 and strength in ASTM A563/A194; the metric series carries both in the DIN/ISO designation.
| Product | DIN (legacy) | ISO / current | ANSI / ASME / inch series | BS | What this mapping means | On this site |
|---|---|---|---|---|---|---|
| Hex nut, metric | DIN 934 (legacy designation) | ISO 4032 — the paired current designation in our sourcing | ASME B18.2.2 hex nut pattern; heavy hex is the wide-body inch counterpart pattern | Confirm at quotation | Pattern and strength are separate decisions in the inch system: ASME B18.2.2 fixes the geometry, ASTM A563 the grade. Two nuts of the same size can be very different nuts depending on grade. | |
| Nylon insert lock nut, metric | DIN 985 (legacy designation) | ISO 10511 was the paired ISO; the current norm is DIN EN ISO 7040 — order whichever your drawing calls out | Confirm at quotation | Confirm at quotation | The polymer insert has a temperature and reuse ceiling; for high temperature or repeated installation the all-metal Stover type is the upgrade path. | |
| Serrated hex flange nut | DIN 6923 (metric) | Ordered under the DIN 6923 designation in our sourcing | IFI 100/107 inch-series counterparts; SAE Grade 5 serrated flange nut is the grade-specified inch member | Confirm at quotation | The flange spreads load without a separate washer and the serrations resist mild vibration at the cost of marking the surface. Match the mating screw strength to the nut grade. | |
| Heavy hex nut, structural (inch) | Not applicable — inch-series product family | Not applicable | ASME B18.2.2 heavy hex with ASTM A563 grade (A325 Type 1 pairs with A563 C/C3/D/DH/DH3 or A194 2H; A490 Type 1 with DH/DH3 or 2H) | Confirm at quotation | Structural RFQs name both the pattern and the grade (for example "heavy hex nut, ASTM A563 Grade DH, 1"-8 UNC") — geometry alone does not buy the right nut. |
Washers: plain, fender, spring and hardened
Washer designations map cleanly across systems as long as you match the function first — bearing (plain), load spreading (fender), vibration (spring) or structural hardness (F436).
| Product | DIN (legacy) | ISO / current | ANSI / ASME / inch series | BS | What this mapping means | On this site |
|---|---|---|---|---|---|---|
| Plain flat washer, metric regular series | DIN 125 Form A/B | ISO 7089 — the counterpart our sourcing names | USS and SAE flat washers are the inch-series regular-series counterparts (per their pages: "metric counterpart DIN 125 / ISO 7089") | Confirm at quotation | The 200 HV plain washer serves assemblies up to property class 8.8; class 10.9/12.9 joints need a hardened washer so the nut face does not embed. | |
| Fender washer, large OD, metric | DIN 9021 | ISO 7093 — the large-series counterpart our sourcing names | Confirm at quotation | Confirm at quotation | Step up from DIN 125 over slotted/oversized holes or soft sheet; over a normal clearance hole in solid material the extra diameter adds nothing. | |
| Helical spring lock washer | DIN 127 (DIN 7980 high-collar under socket cap screws) | Ordered under the DIN 127 designation in our sourcing | ASME B18.21.1 — the inch-series counterpart our sourcing names | Confirm at quotation | Suits slight-to-moderate vibration. Neither system's spring washer is a substitute for a properly selected locking method in high-vibration joints. | |
| Hardened structural washer | Not a DIN product family in our sourcing | F436M is the metric variant of the inch standard | ASTM F436 — Type 1 carbon steel HRC 38–45, Type 3 weathering; mandatory with F3125 A325/A490 and over slotted holes | Confirm at quotation | Never substitute a plain unhardened washer where F436 is specified — the plain washer embeds under preload. This is the most common field error. |
Threaded rod and studs
Threaded rod shows the sharpest version-status lesson in the catalogue: the withdrawn standard is still the best-known designation.
| Product | DIN (legacy) | ISO / current | ANSI / ASME / inch series | BS | What this mapping means | On this site |
|---|---|---|---|---|---|---|
| Fully threaded rod, metric | DIN 975 — formally withdrawn, absorbed into DIN 976-1; still the trade's most-ordered designation | DIN 976-1 — the current document to cite on new specifications (6g thread to ISO 965-2, product grade A to ISO 4759-1) | Stud bolting runs under ASME B18.31.2 with ASTM A193 materials (our collected sources) | Confirm at quotation | Same physical product, different document status. Order by DIN 975 if your installed base uses it; cite DIN 976-1 on new specs — it adds end-marking and length-tolerance clauses the legacy designation never carried. DIN 976-2 is NOT partially threaded rod — it covers interference-fit (MFS) studs. | |
| Stud bolt, high temperature/pressure (inch) | Not applicable — inch-series product family | Not applicable | ASTM A193 Grade B7 stud bolts (the grade our sources tabulate); mating nuts per ASTM A194 | Confirm at quotation | Grade B16 is a separate grade outside our current range — register it in your RFQ and we will confirm availability. | |
| Fully threaded rod, Chinese standard | GB/T 15389-2025 is NOT an equivalent adoption of DIN 975:1986 — our sources state the 1994 version had been adopted non-equivalently and the 2025 revision supersedes it | Treat GB/T 15389 and DIN 976-1 as separate designations, not substitutes | Confirm at quotation | Confirm at quotation | When a drawing and a supply-region standard differ, name both in the RFQ and let the tolerance class decide — do not assume the mapping. |
Coatings and surface finish callouts
Coating standards convert across systems more cleanly than fastener geometry — but test methods differ slightly even where the performance figure matches, so the substitution should be documented.
| Product | DIN (legacy) | ISO / current | ANSI / ASME / inch series | BS | What this mapping means | On this site |
|---|---|---|---|---|---|---|
| Zinc flake coating | Not applicable | ISO 10683:2018 — and BS EN ISO 10683:2018 is the identical British adoption (same technical content) | ASTM F1136 Grade 3 is closely equivalent (both minimum 720 h salt spray, chromate-free) but test methods differ slightly | BS EN ISO 10683 — identical to ISO 10683:2018 per our sources | If the drawing calls for ISO 10683, confirm with the customer that ASTM F1136 is acceptable and document the substitution. Coating callouts also need friction class, mating condition and sealer requirements to hold installation torque consistent. | |
| Zinc-nickel and PTFE coatings | Confirm at quotation | Confirm the exact ISO callout for your environment at quotation | Confirm at quotation | Confirm at quotation | Coating selection is environment-driven — see the coating selection article before fixing a designation. |
Where a designation is missing
These tables cover the families and designations our sourcing has already traced. If your drawing names a standard we have not tabulated — a JIS callout, an ASME part outside the inch families above, or a national designation we list as Confirm at quotation — put the full callout in your RFQ. We confirm it against the current standard edition and tolerance class before quoting, and we would rather mark a cell open than guess at a substitution.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support