GB713-2014 Q345R Steel Plate for shipbuilding 1 grade: Q345R(ASTM Grade B) 2 Corresponding standard: GB 713-2014 Steel plates for boilers and pressure vessels 3 Category: Carbon Steel The lower limit of C content may not be required upon agreement between the supplier and the buyer and indicated in the contract. For steel plates with a thickness greater than 60mm, the upper limit of carbon content can be increased to 0.22%. According to the requirements of the buyer, the carbon equivalent can be specified, and the value shall be agreed by both parties. Carbon equivalent calculation CEV(%) C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15. Total aluminum content. Trace amounts of niobium, vanadium, and titanium may be added to the steel, and their content should be filled in the quality certificate, and the total content should not exceed 0.050%. The content of chromium, nickel and copper as residual elements should not exceed 0.30%, and the content of molybdenum should not exceed 0.080%, and the total content of these elements should not exceed 0.70%. If the supplier can guarantee, the analysis may not be carried out.