Purpose and Benefit of Bend Testing
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.