Weld-on bending test
The weld-on bending test according to SEP 1390 (STAHL-EISEN test sheet of the Association of German Ironworkers ) is a test for the ability of a steel material to absorb cracks.
According to DIN 18800-7, steel specimens with a thickness greater than 30 mm are tested, provided they are welded components and the seams are subjected to tensile or bending stress.
Sample preparation
- A sample of 200 × 500 mm is cut out of the raw material.
- The sample is marked with the material and batch before it is cut off (e.g. hard stamp).
- Milling a groove of approx. 250 mm in the middle of the surface.
- Place a weld bead on the groove. ( Manual arc welding )
Bending test
The sample is now placed upside down (weld bead below) on two support rollers. A pressure body now deforms the steel sample up to an angle of 60 °.
A test has passed if:
- the material is still in one piece
- the crack formation is not greater than 80 mm to the right and left of the weld bead.
Equivalence criteria for the weld-on bending test
In the new version of DIN 18800-7: 2008, equivalence criteria have been formulated which make it possible to dispense with the costly and time-delayed weld-on bending test:
For thicknesses greater than 30 mm or ≤ 80 mm:
- S235: For normalizing rolled grades (addition + N) or thermomechanically treated (addition + M)
- S275 and S355: as fine-grained steel, normalized rolled grades (addendum N) or as cold-tough variants (addendum NL) or thermomechanically treated grades (addendum M) or as cold-tough variant (ML)
For thicknesses> 80 mm:
- S235: like thicknesses greater than 30 mm or less than or equal to 80 mm
- S275 and S355: as fine-grain steel, however, only low-temperature variants (addition NL) or (addition ML)
Individual evidence
- ↑ Beuth Verlag: DIN 18800-7: 2008, element (506), table 100