What Does
Bend Test Mean?
A bend test is a method for measuring stiffness and yield properties of certain materials. Bend tests for ductility provide a simple way to evaluate the quality of materials by their ability to resist cracking or other surface irregularities during one continuous bend. In certain cases the bend test can determine tensile strength.
Bend tests are common in springs and brittle materials with linear failure behaviors like:
- Concrete/stone
- Wood/plastic
- Glass/ceramics
- Powder metallurgy-processed metals and materials
Bend tests are also known as bending tests.
Corrosionpedia Explains Bend Test
The bend test is a simple and cheap qualitative test that can be employed to evaluate both the ductility and soundness of a material. It is often used as a quality control test for butt-welded joints, having the advantage of simplicity of both test pieces and equipment.
No expensive test equipment is needed, test specimens are easily prepared and the test can, if required, is carried out on the shop floor as a quality control test to ensure consistency in production. A standard specimen is bent through a specified arc, and in the case of strip, the direction of grain flow is noted and whether the bend is with or across the grain.
The bend test is popular in welding. A guided bend test is used to determine how strong a weld is after it has been created. A special machine is used to perform the guided bend test. The material must be able to bend up to a specific angle, such as 180 degrees, without any cracks appearing. If this happens, the weld has passed the test. No reversal of the bend force is employed when conducting these tests.
Types of bend tests include:
- Guided-bend test
- Semi-guided bend test
- Free-bend test
- Bend and flatten test
There are no standardized terms for reporting bend test results for broad classes of materials; rather, terms associated with bend tests apply to specific forms or types of materials. For example, a bend test for ductility of welds is given in ASTM E-190.