What is the difference between elongation A and AGT?
The breaking elongation A is the ductility index of the reinforcement, but it is only the resident elongation of broken region rather than the ductility of the reinforcement.Total elongation rate of maximum load Agt denotes the elongation up to ultimate load without reduction of cross section.
Usually elongation, A, has double the value of Agt.
The ductility of Agt > 5% is required for the finished hollow-bar,not for the steel tube it is manufactured from and which is given on the mill certificate of the steel mill.
（By Titan I ASTM A370）