SA285 is a pressure vessel carbon steel plate utilized for applications requiring low or intermediate tensile strength. This grade is used in the manufacture of storage tanks and low pressure, temperature controlled vessels. Request Info. Mechanical Properties A285 Gr C:Tensile:55 to 75 ksi.ASTM A285 Grade A|A285 Gr.A|A285GrA Vessel Steel Plate Gangsteel is specialized in supplying ASTM A285 steel plate in A285 grade A. For more information of A285 grade A steel plates, please check them in following:A285 grade A Chemical Composition. Grade. The Element Max (%) C. Si. Mn. P. S. A285 grade A. 0.17. 0.08-0.45. 0.98. 0.035. 0.035.