Technological Bend Test
The technological bend test checks the formability of materials or welded joints by bending around a defined angle. It examines whether cracks form in the outer fiber zone.
Physical-Chemical Mechanism of Action
The technological bend test involves bending a material or weld seam to a specified angle, usually 90°. During bending, the outer fiber zone is subjected to plastic strain. If the material is too hard or too fine-grained, cracks can form.
Metallurgical Relevance & Welding Risks
The bend test shows whether the weld and surrounding material are sufficiently ductile. A negative result indicates excessive hardness or too fine a grain distribution, which can lead to cracks. This can impair the load-bearing capacity of the joint.
Workshop Practice & Instructions
For the technological bend test, use a specimen with a defined diameter and length. Bend it to an angle of 90°. The maximum strain in the outer fiber zone should not exceed 1.5 %. If this limit is exceeded, the weld is too hard or fine-grained and must be redone.