DIN 50137 is a withdrawn DIN standard that describes a ring expanding (ring mandrel) test used on steel tubes to evaluate ductility and reveal manufacturing defects that appear during expansion.
This method is commonly referenced in tube and hollow-section quality programs where an expanding operation (or service deformation) is a concern. If you need help mapping an older DIN 50137 callout to a current requirement, talk with our team.
DIN 50137:1979-06 — Testing of steel; ring expanding test on tubes
DIN 50137 (edition 1979-06) is a mechanical test method for steel tubes based on expanding a short ring specimen with a mandrel to assess plastic deformability and to expose defects that can open up as cracks during expansion.
The standard is withdrawn. For most current specifications and audits, it is important to confirm whether the purchaser accepts a replacement standard and which edition is contractually controlling.
Quick definition
Ring expanding test for steel tubes: a ring cut from a tube is expanded using a mandrel, and the tube material is evaluated based on its behavior during expansion (commonly including crack appearance and any required expansion target set by the invoking specification).
What this standard covers
DIN 50137 covers a ring expanding test applied to steel tubes. The intent is to check ductility/expandability and to help identify production defects in the tube wall that may become visible when the ring is expanded.
DIN 50137 itself is a test method, but the acceptance criteria (for example, what constitutes a “pass” for a given product) is often defined by the product specification or purchasing requirement that cites the test.
Why this standard matters in testing
Tube products may be required to tolerate local plastic deformation during fabrication steps such as flaring, forming, or expansion into joints. A ring expanding test provides a practical way to screen for inadequate ductility and for discontinuities that can propagate as cracks under expansion.
When DIN 50137 is cited on legacy drawings or long-lived equipment programs, the most important practical step is ensuring the lab and customer align on the replacement standard and the required reporting/acceptance basis.
Common materials, product types, or applications covered
Typical products: Steel tubes where expandability and freedom from expansion-induced cracking are important.
Typical uses: Receiving inspection, supplier qualification, process change validation, and comparative evaluation of tube lots intended for forming or expansion operations.
Common test or verification workflow
Most workflows using this method follow a practical sequence: cut a ring from the tube end, perform controlled mandrel expansion on a compression-capable test frame or press, and evaluate the ring for cracking or other specified indications.
Common outputs: Pass/fail against specified acceptance criteria, notes on crack appearance/location, and basic specimen identification tied to the tube heat/lot.
Equipment commonly used for this standard
DIN 50137 generally points to a compression-capable loading system and a dedicated ring-expansion tool set designed to expand a ring specimen with a conical mandrel in a controlled, aligned manner.
Common equipment: Universal testing machine (or equivalent press/test frame), compression platens, ring-expanding fixture with conical mandrel, and guarding appropriate for sudden fracture.
Quoting caution: Fixture geometry, mandrel angle/finish, alignment features, and how the lab defines/records the expansion endpoint should be matched to the customer’s controlling replacement standard and any product-spec acceptance language.
How to read this designation or revision
Common citation: DIN 50137:1979-06.
Status: Withdrawn DIN standard. If DIN 50137 is referenced in a contract, the parties typically need to agree whether testing is performed to the legacy document or to an accepted replacement.
Related standards, methods, or frameworks
DIN 50137 has been replaced by later European/international documents for similar ring expanding testing of tubes. Commonly referenced replacements include DIN EN 10236 and DIN EN ISO 8495 (confirm the exact edition required by the invoking specification).
Get help selecting a DIN 50137 replacement setup
If you are configuring a test frame and ring-expansion tooling for tube expandability testing, you can request a detailed quote for a system matched to your force range, specimen geometry, and reporting needs.