Theory
A simple bend test gives satisfactory means of obtaining ductile. Ductility is judge by mean of non breaking of metal under the condition of test for wires and steel metals simple bend test for wires and steel metals. Simple bend test is used as an orbitary measured of relative flexibility for ductile materials in the form of rod, such as reinforcement bars of concrete. A cold bend test is used to determine wheather or not the rod can be bend shaping without cracking and serves as on acceptance test for this form of ductility.
Objectives
1. To observe the appearance of bent portion.
2. To interpret the observation.
Reference
Test procedure as per I.S. 1599
Apparatus
1. Roller with loading device
2. Specimen
3. Scale
Diagram
Procedure
Two types of tests performed in bending test
A. Simple bend test
1. Adjust the two parallel roller supports at a distance D + 3a between these rollers.
2. Lay the test piece on them.
3. Bend it by middle by mean of a gradually applied load by means of a mandrel such that α = 900
4. Observe the bend portion, cracks on the specimen and ductility of bar.
B. Free bend test
1. Lay the above bend specimen directly on the ends of the two legs of the test piece.
2. Apply the steady pressure on the specimen until the legs become parallel to each other.
Precaution
1. Any lateral displacement of the specimen is prevented by ensuring exit loading.
2. The initial radious of the curvature of the bend is kept constant while bending.
Observation
The specimen is free from any cracks and damage.
Conclusion
The specimen shows good ductility and therefore it can be recommended as reinforcement.
