Purpose and Benefit of Bend Testing
Bend testing is an easy qualitative test mostly and mainly used for the evaluation of both the material soundness and ductility. At Applied Technical Services, we frequently assess the quality of butt-welded joints using this method. The bend test is performed by using a sample coupon that is bent in three point bending to a specified angle.
Failure of a sample coupon is revealed on the exterior part of the bend when it is plastically deformed exposing weld defects or embrittlement of the material. A bend test is performed by wrapping a coupon around a mandrel of a specified diameter through a specified angle, and is the kind of test typically identified in a welding qualification specification and/or welder procedure. The bend angle may be from 90° to 180° depending on the requirements specified.

The diameter of the mandrel that the test specimen is bent over is identified in the test specification or standard and it differs with the material’s ductility and strength. When testing for welder qualification or for butt/groove welding procedure, sample may be oriented parallel or transverse to the welding direction. The transverse face bend specimen will disclose any defects on the face such as lack of sidewall fusion or excessive undercut close to the cap, opposite to the root bend in which it identifies lack of penetration or root fusion. There is also a side bend test, typically conducted on thicker materials. 

Common Reasons to Request This Method:
Performed to Following Standards:

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