方管，是方形管材的一種稱呼，也就是邊長相等的的鋼管。在抗彎、抗扭強度相同時，重量較輕，所以廣泛用于制造機械零件和工程結構。方管廣泛用于建筑，機械制造，鋼鐵建設等項目，在造船，太陽能發電支架，鋼結構工程，電力工程，電廠，農業和化學機械，玻璃幕墻，汽車底盤，機場,鍋爐建造，高速路欄桿，房屋建筑，壓力容器，石油儲罐，橋梁，電站設備，起重運輸機械及其他較高載荷的焊接結構件也有大量使用。

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. 

方管規格尺寸

Square Pipe Specification and Dimension

方管的規格標示方法：主要是以邊寬*邊寬*管壁厚度表示。如16×16×0.4～1.5則表示邊寬為16mm，管壁厚度為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.

方形鋼管規格尺寸

Specification and Dimension of Square Steel Pipe

方管分類

Square tube classification

按生產工藝分：熱軋無縫方管、冷拔無縫方管、擠壓無縫方管、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.

按材質分： 普碳鋼方管、低合金方管。普碳鋼分為：Q195、Q215、Q235、SS400、20#鋼、45#鋼等；低合金鋼分為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.

按斷面形狀分類：(1)簡單斷面方管——方形方管、矩形方管(2)復雜斷面方管——花形方管、開口形方管、波紋形方管、異型方管

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

按表面處理分： 熱鍍鋅方管、 電鍍鋅方管、涂油方管、酸洗方管

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

按用途分類——裝飾用方管、機床設備用方管、機械工業用方管、化工用方管、鋼結構用方管、造船用方管、汽車用方管、鋼梁柱用方管、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

按壁厚分類—— 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

方管重量計算

Square tube weight calculation

方管重量計算公式：重量={（長-壁厚）×2÷1000+（寬-壁厚）×2÷1000}×7.85×壁厚×長度。常用規格理論重量見下表。

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.

備注：以上單位為kg/m，其中壁厚和邊長的單位為毫米，即mm。

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