Most of the square tubes are steel tubes, which are unpacked, flattened, curled, and welded to form round tubes, which are then rolled into square tubes and then cut to the required length. Generally, there are 50 pieces per pack of Shen'ao square tubes. Most of the large sizes in stock are 10*10*0.8-1.5~~500*500*10-25. The square tubes are used for structural square tubes, decorative square tubes, and construction square tubes. , mechanical square tube, etc.

The formula for calculating the weight of a square tube is: (side width a+side width b-2.8584×wall thickness)×wall thickness×0.0157×length, pay attention to the calculation unit (the unit of side width and wall thickness is millimeters, and the length is meters). This method is also suitable for the calculation of KQJ and KQF hollow steel. This method is relatively simple and easy to remember, and is commonly used in industrial and mining enterprises.
The length of the square tube section is a, the width is b, the back of the wall is c, the length of the square tube is l, and the density of the square tube is p, then
Weight=(ab-(a-2c)(b-2c))×l×p
=2c（a+b-2c)×l×p
=2clp(a+b-2c)
Substitute the above numbers into the above formula to find the weight of the square tube. But pay attention to the units of each value
Delivery weight calculation formula and allowable deviation
(1) Side length*4*wall thickness*7.85*length
(2) 4*wall thickness*(side length-wall thickness)*7.85*length
Generally (1) commonly used. For example, the length of 40MM*20MM*1.5MM square tube is 850MM, which is:
(20+40)*2*1.5*7.85*850=0.012 tons