Farmeru2019s copper ltd. maintains an extensive inventory of cast iron, class 40, in solid and rectangle bar. cast iron possesses the highest strength, hardness, resistance to wear and heat treat response for an unalloyed gray iron. it is widely used for bearing and bushing applications in the hydraulics industry. tensile strength runs from 27,000-40,000 psi depending on section size. typical cast iron u2026 Class 40 gray cast iron flat has a wide variety of uses and can be cut to any size to suit your application's needs. Tdc 40, cast iron, grade 1. tdc 40 is a heavy-duty, cat iron body, grade 1 door closer that is ansi/bhma certified and ul rated. Astm a48 class 40 gray cast iron astm a48 no. 40 is a middle grade of gray cast iron in usa. there is no equal grade for other countries. in china, it could be taken as the grade between ht250 and ht300, or between gg25 and gg30.