DIN 975 Threaded Rod Equivalent: DIN 976-1, UNI 6547, ASME B18.31.1M and ISO
DIN 975 is the withdrawn German reference traditionally used for fully threaded metric rods, threaded bars and all-thread rods. It remains common in legacy drawings, catalogues and purchase enquiries, especially for HVAC suspension, cable trays, machinery and general fastening.
DIN 975 and DIN 976-1
DIN 976-1:2016-09 is the current DIN reference for metric stud bolts. It continues the product family associated with DIN 975, but should not be declared technically identical in every detail. Editions may differ in thread tolerances, product grade, marking and delivery requirements.
For new designs, specify the applicable DIN 976-1 form, size, length, material, property class, finish and tolerances. For a legacy drawing, retain DIN 975 and verify the proposed DIN 976-1 product against the original requirements.
Is there a direct ISO equivalent?
No single ISO product standard replaces DIN 975. The relevant ISO references serve different functions:
| Standard | Function |
|---|---|
| ISO 898-1 | Mechanical properties of applicable carbon/alloy steel fasteners |
| ISO 965 series | Metric thread tolerances and limits |
| ISO 261 / ISO 262 | Metric thread diameter and pitch selection |
| ISO 3506 series | Stainless-steel fastener properties where applicable |
These standards complement the threaded-rod product specification; they do not define the complete DIN 975 product.
DIN 975 vs UNI 6547
UNI 6547 is the closest Italian product counterpart commonly found in purchasing catalogues. It is frequently listed with DIN 975 for metric threaded bars. Confirm diameter, pitch, length, tolerance, material, property class and finish before treating the two references as interchangeable.
DIN 975 vs ASME B18.31.1M
ASME B18.31.1M is the closest American metric functional comparison for continuous-thread and double-end studs. It is not an automatic dimensional replacement: verify thread series, diameter, length ranges, end requirements and tolerances. Do not confuse it with ASME B18.31.3, which covers inch-series threaded rods.
DIN 975 and JIS references
JIS B 0205 covers the Japanese/ISO metric thread system, not a complete DIN 975 threaded-rod product. JIS B 1051 covers mechanical properties for carbon/alloy steel fasteners. Neither is a direct product equivalent.
Product, material and property class
DIN 975 identifies the legacy threaded-rod product, not a material grade. A callout such as DIN 975 M20 × 1000, 8.8 combines the legacy product reference, metric size and property class. Material, surface treatment, thread tolerance and inspection requirements should be stated separately.
Common commercial lengths include 1000, 2000 and 3000 mm, but length alone does not establish equivalence. A supplier should confirm straightness, end condition, thread quality, coating and cut-length tolerances.
How to select a replacement
Compare the complete specification:
- Nominal diameter and pitch.
- Full-thread length and overall length.
- Thread tolerance and end condition.
- Material and property class.
- Surface treatment and corrosion requirement.
- Straightness, marking and inspection documents.
Final recommendation
DIN 975 is a withdrawn legacy designation. DIN 976-1 is the current DIN route; UNI 6547 is the closest Italian product counterpart; ASME B18.31.1M is a related metric stud reference, not a one-to-one equivalent. For new work, use the current applicable standard and state all dimensions and properties explicitly. For legacy work, verify every critical requirement before substitution.
