ASTM E290 covers Bend Testing for the determination of ductility of metallic materials. This test evaluates the quality of the material by its ability to resist cracking or other surface irregularities during one continuous bend.
Bend testing is performed to determine the ductility of metallic materials, and ASTM E290 outlines the testing procedures for this. Bend testing aids in determining the ductility of a material. Bend testing a material allows the bend strength, fracture strength, and fracture resistance of that material to be determined. Bend testing welds ensures that the weld has fused properly to the parent metal and that there are no faults in the weld itself.
ASTM E290 is divided into four methods for bending the specimen:
➢ Guided Bend ➢ Semi-Guided Bend ➢ Free-Bend ➢ Bend and Flatten
These tests are performed by supporting the two ends of a specimen while loading it at the center with a mandrel or plunger. The test is completed when the designated angle of the bend, or other specified condition, has been reached. Afterwards, the specimen is visually inspected for cracks or defects, and failure is determined by the size of the cracks and imperfections allowed by the material specification.
Longitudinal edges of a rectangular test specimen may be rounded to a radius not exceeding 1.5 mm 1/16 inch) for specimens equal to or less than 50 mm (2 inches), and rounded to a radius not exceeding 3 mm (1/8 inch) for specimens over 50 mm (2 inches) in thickness.
Surface disturbances, such as orange peel, that develop during a bend test, where there is no penetration of the surface, are not considered a crack failure.