方管，是方形管材的一种称呼，也就是边长相等的的钢管。在抗弯、抗扭强度相同时，重量较轻，所以广泛用于制造机械零件和工程结构。方管广泛用于建筑，机械制造，钢铁建设等项目，在造船，太阳能发电支架，钢结构工程，电力工程，电厂，农业和化学机械，玻璃幕墙，汽车底盘，机场,锅炉建造，高速路栏杆，房屋建筑，压力容器，石油储罐，桥梁，电站设备，起重运输机械及其他较高载荷的焊接结构件也有大量使用。

Square pipe is a form of address for square pipe, that is, steel pipe with equal side length. When the bending and torsion strength are the same, the weight is lighter, so it is widely used in manufacturing mechanical parts and engineering structures. Square pipes are widely used in construction, machinery manufacturing, steel construction and other projects, such as shipbuilding, solar power bracket, steel structure engineering, power engineering, power plant, agricultural and chemical machinery, glass curtain wall, automobile chassis, airport, boiler construction, high-speed rail, building, pressure vessel, oil storage tank, bridge, power plant equipment, lifting and transportation machinery and other high-load projects. Welded structural parts are also widely used. 

方管规格尺寸

Square Pipe Specification and Dimension

方管的规格标示方法：主要是以边宽*边宽*管壁厚度表示。如16×16×0.4～1.5则表示边宽为16mm，管壁厚度为0.4-1.5mm。

Specification marking method of square pipe: mainly expressed by edge width * edge width * wall thickness. If 16 x 16 x 0.4-1.5, the width of the edge is 16 mm and the thickness of the tube wall is 0.4-1.5 mm.

方形钢管规格尺寸

Specification and Dimension of Square Steel Pipe

方管分类

Square tube classification

按生产工艺分：热轧无缝方管、冷拔无缝方管、挤压无缝方管、焊接方管。

According to the production process: hot-rolled seamless square pipe, cold-drawn seamless square pipe, extruded seamless square pipe, welded square pipe.

按材质分： 普碳钢方管、低合金方管。普碳钢分为：Q195、Q215、Q235、SS400、20#钢、45#钢等；低合金钢分为Q345、16Mn、Q390、ST52-3等。

According to material quality: plain carbon steel square pipe, low alloy square pipe. Common carbon steel is divided into Q195, Q215, Q235, SS400, 20 # steel, 45 # steel, etc. Low alloy steel is divided into Q345, 16Mn, Q390, ST52-3 and so on.

按断面形状分类：(1)简单断面方管——方形方管、矩形方管(2)复杂断面方管——花形方管、开口形方管、波纹形方管、异型方管

Classified by section shape: (1) Simple section square pipe - square pipe, rectangular square pipe (2) Complex section square pipe - fancy square pipe, open square pipe, corrugated square pipe, special-shaped square pipe

按表面处理分： 热镀锌方管、 电镀锌方管、涂油方管、酸洗方管

According to surface treatment: galvanized square pipe, galvanized square pipe, oiled square pipe, pickled square pipe

按用途分类——装饰用方管、机床设备用方管、机械工业用方管、化工用方管、钢结构用方管、造船用方管、汽车用方管、钢梁柱用方管、特殊用途方管

Classification by use - square pipes for decoration, machine tools and equipment, square pipes for machinery industry, square pipes for chemical industry, square pipes for steel structure, square pipes for shipbuilding, square pipes for automobiles, square pipes for steel beams and columns, square pipes for special purposes

按壁厚分类—— 超厚壁方管、厚壁方管和薄壁方管

Classification by Wall Thickness-Ultra-Thick Wall Square Tube, Thick Wall Square Tube and Thin Wall Square Tube

方管重量计算

Square tube weight calculation

方管重量计算公式：重量={（长-壁厚）×2÷1000+（宽-壁厚）×2÷1000}×7.85×壁厚×长度。常用规格理论重量见下表。

The formulas for calculating square tube weight are as follows: weight={(length-wall thickness)*2_1000+(width-wall thickness)*2_1000}*7.85_wall thickness*length. The theoretical weight of commonly used specifications is shown in the table below.

备注：以上单位为kg/m，其中壁厚和边长的单位为毫米，即mm。

Note: The above units are kg/m, and the units of wall thickness and side length are mm, that is mm.