This specification applies to hot-rolled notch-ductile steel for general structural purposes, suitable for welding, and supplied in the following forms: (i) Plates having a thickness of 0.4 inch (10.2 mm) up to and including 2 inch (50.8 mm); and (ii) Bars having a diameter or width across flats of 0.625 inch (15.9 mm) up to and including 2 inch (50.8 mm). The supply of sections, and the supply of plates and bars outside the ranges given avove, is a matter for agreement between the purchaser and the manufacturer.. The specification covers four grades of notch ductility, designated ND I, NDII, ND III and ND IV, each of which can be supplied in two classes based on tensile strength, viz. Class A and Class B.