Steel Plate Products. Carbon & High Strength Low Alloy (HSLA) Structural Steel Plate. A36; A572 Grade 42, 50, 60, 65; CSA G40.21 Grade 44W, 50W, 50A; A709 Grade 36 Weight Calculators - Weight of a Steel Plate - Radisson ImpexHow to calculate the weight. The weight is easily calculated. Simply multiply the appropriate alloy density by the length, width, and thickness of the required part (see worked example below). Metric. density (g/cm³) x. T. x. W.