Bending Test Of Steel Bar 583612

Practical no#11

Object: Bending test of steel bars. Apparatus: UTM, test specimen, bending table pin. Theory: A bending test is a method for measuring stiffness and yield properties of certain materials. Bending 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 bending test can determine tensile strength. Procedure: 1. Take a test specimen of the steel rod. 2. Measure the diameter of the steel rod. Take at least 3 readings and calculate the mean. 3. Now place the test specimen in the bending table specimen should be kept in the bending table in such a way that the plane 4. Intersecting the longitudinal ribs is parallel to the axis of the pin. 5. Select suitable rang of scale. 6. Start the machine and start applying load continuously and uniformly throughout the bending. 7. As the load is applied on the rod it will start bending. 8. Discontinue the application of load when the angle of bent specified in the material

specimen has been achieved before rebound. 9. Take out the specimen and examine the tension surface of the specimen for cracking.

Specification for Angel in Bend Test: Bar # 3 to Bar #11 should bend up to 180 degree without crack Bar # 14 & Bar # 18 should bend upto90 degree without crack This all specification has been given in AASHTO (American Association for Sate Highway and Transportation Officials.

Bend Test Requirements: Bar No 3, 4, 5 6 7, 8 9, 10 11 14, 18

Grade 40 3 ½ db 5 db -------------------------------------------------------------------------

Grade 60 3 ½ db 5 db 5 db 7 db 7 db 9 db

Grad 75 ------------------------------------------------------------------------7 db 9 db