Sch 1 para 5 Steel vessels
Non-alloy quality steels must meet the following requirements— (a) they must be non-effervescent and supplied after normalisation treatment, or in an equivalent state; (b) the content per product of carbon must be less than 0.25% and that of sulphur and phosphorous must each be less than 0.05% (c) they must have the following mechanical properties per product— (i) the maximum tensile strength Rm, max must be less than 580 N/mm 2; (ii) the elongation after fracture must be: if test pieces are taken parallel to the direction of rolling: or, if test pieces are taken perpendicular to the direction of rolling: (iii) the average bending rupture energy (KCV) for three longitudinal test pieces at minimum working temperature must not be less than 35 J/cm 2 . Not more than one of the three figures may be less than 35 J/cm 2 , with a minimum of 25 J/cm 2 . In the case of steels intended to be used in the manufacture of vessels the minimum working temperature of which is lower than - 10°C and the wall thickness of which exceeds 5 mm, this property must be checked.