矩形管其實是由于其橫截面是方形而命名的，從外形來說方管與圓管最顯而易見的區別就是其橫斷面，方管是方形的圓管是圓形的。其中方管是屬于異形管。
In fact, the square tube is named because the cross section is square. From the shape, the most obvious difference between the square tube and the circular tube is its cross section. The square tube is round. The square tube belongs to the special-shaped tube.
這種橫斷面非圓形的異形管與圓管相比，有較大的慣性矩和截面模數，有較大的抗彎、抗扭能力，從結構來說更加優秀，能夠減輕自身重力和節省鋼材的優點。所以方管廣泛運用于建筑，鋼結構工程，鋼鐵建設等工程建造項目，以及電力工程，除了建筑和電力行業還運用于機械制造，農業和化學機械，起重運輸機械。
Compared with the circular tube, the non circular cross-section tube has larger inertia moment and cross section modulus. It has greater bending and torsion resistance, and is better from the structure. It can reduce the advantages of self gravity and save steel. So the square tube is widely used in construction, steel construction, steel construction and other engineering construction projects, as well as electric power engineering. Besides the construction and electric power industry, it is also used for machinery manufacturing, agriculture and chemical machinery, and heavy transportation machinery.
矩形管的分類方式多樣化，所以我們方管的細類有很多，更何況不同方管廠家的產品又會有很大的差異，如果方管按照我們方管的表面處理種類可以分為熱鍍鋅方管、電鍍鋅方管、涂油方管以及酸洗方管等等。
The classification of the square tube is diversified, so there are a lot of fine categories of our square tubes. Moreover, there will be a lot of difference in the products of different square tube manufacturers. If the square tube can be divided into hot-dip galvanized square tube, galvanized galvanized square tube, oil coating square tube and acid washing square tube, the surface treatment types of our square tube can be divided.
在玻璃幕墻材料中使用比較廣泛的是熱鍍鋅方管。
Hot-dip galvanized square tubes are widely used in glass curtain wall materials.
矩形管如果按生產工藝來劃分，則可分為熱軋無縫方管、冷拔無縫方管、擠壓無縫方管以及焊接方管等等。無縫方管顧名思義就是沒有焊縫的鋼管，無縫方管的應用挺廣的。大部分方管是由無縫圓管加工而成的，而相較于圓管，方管具有大抗拉強度，質量輕的優點。
If the square pipe is divided according to the production process, it can be divided into hot-rolled seamless square tubes, cold drawn seamless square tubes, extruded seamless square tubes and welded square pipes. Seamless square tube, as the name suggests, is seamless steel pipe, seamless square tube is widely used. Most of the square tubes are made of seamless tubes. Compared with round pipes, the square tube has the advantages of large tensile strength and light weight.