DIN 50139 is a legacy German test method for evaluating tube end flanging performance on steel tubes. It is commonly referenced when a buyer needs a simple, destructive formability check to see whether a tube end can be flanged without unacceptable cracking or splitting.
DIN 50139 has been withdrawn and later superseded by newer EN/ISO documents for tube flanging tests. If you need help mapping a customer or drawing note that still cites DIN 50139 to a current method and suitable test tooling, you can contact our team.
DIN 50139: Testing of steel — flanging test on tubes
DIN 50139 is a short, older DIN document (published as DIN 50139:1965-11) focused on the flanging test for tubes. In practice, it is used to assess whether a steel tube end can be formed into a flange using a defined tool arrangement and forming sequence, while observing for cracking and other formability-related failures.
Because it is a withdrawn standard, DIN 50139 is most often encountered as a legacy requirement in older specifications, drawings, and long-life industrial assets (for example, piping or tube-based components that remain in service for decades).
Quick definition
Standard type: Test method (tube formability / tube end forming).
What it evaluates: The ability of a steel tube end to undergo plastic deformation during flange formation, typically judged by visible cracking or splitting and the achieved flange formation.
What it is not: A material specification or acceptance standard by itself; it is a method that supports product requirements and manufacturing controls.
What This Standard Covers
DIN 50139 addresses the flanging test applied to tubes, historically presented as “Testing of steel; flanging test on tubes.” The method is associated with controlled forming of the tube end using dedicated tooling, followed by inspection of the formed end for defects that indicate limited ductility or poor forming quality.
In many procurement and QA contexts, a flanging test is used as a quick process capability check for tube lots, heat batches, or incoming material when tube end forming is a critical manufacturing step.
Why This Standard Matters in Testing
Tube end flanging is common in assemblies where a flared or flanged end is needed for joining, sealing, or mechanical retention. A standardized flanging test supports consistent pass/fail decisions and helps reduce the risk of in-service leakage, pull-out, or crack growth that can originate from forming defects.
For lab managers and production teams, this type of method is often part of a broader forming-quality and mechanical-property picture (for example, used alongside tensile tests, hardness checks, or additional tube formability tests).
Common Materials, Product Types, or Applications Covered
DIN 50139 is associated with steel tubes where end flanging is relevant. Typical use cases include general tube products that undergo secondary forming operations at the end of the tube (such as creating a flange for assembly integration), where ductility and forming behavior are important.
Because tube geometry and manufacturing route strongly influence formability, matching the test setup to the tube size range and the cited edition is important when DIN 50139 is invoked in legacy documentation.
Common Test or Verification Workflow
A typical workflow for a tube flanging test includes:
- Cutting and preparing a tube test piece to the required length and end condition.
- Forming the tube end into a flange using a defined tool set (commonly involving a forming mandrel or conical tool and a controlled forming stroke).
- Inspecting the formed flange for cracks, splits, and other visible signs of inadequate formability.
- Reporting the result as a pass/fail outcome (and, where required by the controlling specification, recording key dimensions or observations).
Revision sensitivity: When DIN 50139 is cited, the exact edition, tooling geometry assumptions, and acceptance criteria are often controlled by the calling drawing/specification or by the superseding EN/ISO method used for compliance.
Equipment Commonly Used for This Standard
DIN 50139-style flanging tests typically rely on a stable force application system and dedicated forming tooling sized to the tube dimensions.
Common equipment: Universal testing machines (UTMs) or equivalent press frames, compression platens/adapters, tube-end flanging tooling (mandrels/cones and supports), and basic dimensional and visual inspection tools.
Practical quoting considerations: Tube outside diameter and wall thickness range, expected forming force, tool material, and how the tube is supported/aligned during forming usually drive the equipment configuration more than the standard number itself. If you are sourcing a machine or a tool set for repeated tube flanging work, you can request a detailed quote based on your tube sizes and target throughput.
How to Read This Designation or Revision
Common citation: DIN 50139.
Known edition in DIN standard records: DIN 50139:1965-11.
Status: Withdrawn. DIN catalog records indicate it was replaced by DIN EN 10235:1994-01 and later by DIN EN ISO 8494 (tube flanging test).
When a customer specification still calls out DIN 50139, it is good practice to align on the intended test intent (flange formation and defect evaluation) and then confirm which current EN/ISO document (and acceptance criteria) the buyer wants to use for compliance and reporting.
Related Standards, Methods, or Frameworks
DIN catalog replacement references commonly associated with DIN 50139 include DIN EN 10235 and DIN EN ISO 8494 (metallic materials — tube — flanging test). Where a contract or drawing transitions from DIN 50139 to a newer method, the controlling document should define which edition to use and what constitutes acceptance.
Talk with us about matching DIN 50139 intent to today’s test setup
If you are working from a legacy DIN 50139 callout and need help selecting tooling, confirming the right superseding method to cite, or configuring a UTM/press frame for your tube sizes, talk with our team and share the tube dimensions and the requirement text from your drawing or specification.