ASTM A736 Grade C is a kind of low Carbon, age-hardening, Ni-Cu-Cr-Mo alloy steel plates material used to fabric pressure vessels. A736 is divided into two grades or levels : A736 Grade A and A736 Grade C . jwvivian98 (at) yahoo (dot) com Skype jw-vivian (at) hotmail (dot) com Standard: ASTM A736/A736M Thickness :3mm -500mm Width :1000mm-4000mm Length :1000mm-18000mm