TMT Bend & Rebend Test — Mandrel Calculator

Select the test, bar diameter and steel grade to calculate the mandrel diameter.

Maximum Mandrel Diameter for Bend Test
60 mm
3 × 20 mm = 60 mm
Bend test — Table 4
TEST CONDITION Cold bend — sides parallel
MANDREL FACTOR 3φ
Bend test: The bar is bent cold over the specified mandrel by continuous pressure until the sides are parallel. The bend-test table gives the maximum mandrel diameter.

Rebend test: The specimen is first bent to an included angle of 135°, aged in boiling water at 100°C for 30 minutes, cooled, and then bent back to an included angle of 157.5°. The rebend table gives the minimum mandrel diameter.
Reference basis: IS 1786:2008, including Amendment No. 3 (March 2017). Verify the current applicable edition/amendments and project specification before laboratory testing.