HRB400 (III.) grade steel bar;  straightening;  Mechanical properties

The fine-diameter steel bars used in the project are all disc circular before entering the field, and need to be straightened before use. The mechanical properties of the 400,6,8 mm diameter steel bar with a diameter of 10,400,5 mm in the newly launched HRB400(III.) grade steel bar were experimentally studied. Through the comparative analysis of the test results, it is concluded that the strength (yield strength and tensile strength) of HRB<> (III.) grade fine diameter steel bar after straightening is slightly reduced or basically flat. In terms of ductility, the elongation δ<> increased slightly, and the uniform elongation δgt decreased slightly, but the performance indicators still met the requirements of the standard specifications and had a certain surplus. In engineering applications, the influence of straightening process on the properties of HRB<> (III.) grade fine diameter steel bar can be ignored, and at the same time, uniform elongation δgt is used instead of elongation δ