4 * Thickness * (side length - thickness) * 0.00785

Among them, the side length and wall thickness are in millimeters (mm), and the value is directly substituted into the above formula, which is the weight of the square tube per meter, in kilograms.

For a 30 x 30 x 2.5 mm square pipe, the weight per meter can be calculated according to the above formula: 4 x 2.5 x (30-2.5) x 7.85=275 x 7.85=2158.75 grams, that is, about 2.16 kg.

When the wall thickness and side length are in millimeters, 4x wall thickness x(side length - wall thickness) calculates the volume of the square tube per meter length, in cubic centimeters (cm3) as a unit, multiplied by the specific gravity of iron 7.85 grams per cubic centimeter, resulting in the weight of the square tube per meter in kilograms.