Tube formula = 0. 00785 x block area (square mm)
= 0. 00785x0. 25xs
Outer diameter 2-2 wall thickness 2
= 0. 00785 x 0. 25 x 3. 14159 x (d2-d2+4d thickness-4 wall thickness2)
=0. 00785 x 0. 25 x 3. 14159 x 4 x (exterior-wall thickness) x wall thickness
= (extra-wall thickness) x wall thickness x 0. 02466 (kg/m)
This is how the title formula works。
Extension:
Steel having an empty section, much longer than a diameter or perimeter。
(b) circles, squares, rectangles and alien steel tubes by cross-section shape; carbon-structured steel tubes, low-alloy structure steel tubes, alloy steel tubes and composite steel tubes by mass; and transmission pipelines, engineering structures, heat engineering equipment, petrochemical industry, mechanical manufacturing, geo-drilling, high-pressure equipment steel pipes by use; it's divided into seamless steel pipes and welded steel pipes by production process, with seamless steel pipes divided into hot and cold rollers. (b) two types of welding pipe, which are also divided into straight welding tubes and screwdrivers。
The tubes can be divided into two main categories according to the method of production: seamless steel pipes and suture steel pipes, with a short suture steel pipe。
1 the seamless steel pipe can be divided into the following methods of production: hot-rolling seamless pipe, cold-deep tube, precision steel pipe, thermal amplification tube, cold voltage tube and squeeze pipe。
The seamless steel pipe is made of high-quality carbon steel or alloy steel, with thermal and cold-throwing (pushing)。
2. Welding steel tubes are divided into furnaces, electric welding (e. G. Welding) tubes and automatic arc welding tubes because of their different welding forms, and direct welding and helving tubes because their end shapes are also divided into round welding and welding (square, flat, etc.)。
Welded steel tubes are made of steel plates that are curled into tubes, welded in pairs or spirals, which are divided into welded tubes for low-pressure fluid transport, screwdrivers, direct rollers, welded tubes, etc. A seamless steel pipe can be used in various industries, such as liquid gas piping and gas piping. Welding lines can be used for water pipelines, gas pipelines, heating pipes, electrical pipes, etc。
The tube crosses a circle。
The circle corresponds to the circle of an empty centre, with a small radius (r) and a large radius (r) for the entire circle, the radius of the circle minus the radius of the hollow circle being the width of the circle. The example of life is the presence of heart tubes, donuts, rings, etc., and the removal of fan rings that are part of the circle。
Circle area: outer area - inner area = round rate x (large radius square - small radius square) = zirconium (rxr-rxxr) = zirconium (r2-r2)。
There's another way:
S-r-r-o-r-r-e-r-e-r-e-s
(r-r)x (r+r)
R = large circle radius
R = circle width = large circle radius - small circle radius
