方管是方形管材的一種稱呼，也就是邊長相等的的鋼管。304方管是帶鋼經過工藝處理卷制而成。304方管的表面覆蓋著各種保護層，將304方管和腐蝕性介質隔開，無縫方矩管就是防止304方管腐蝕有用的方法。

Square pipe is a name for square pipe, that is, steel pipe with equal side length. 304 square tube is rolled from strip steel after process treatment. The surface of 304 square tube is covered with various protective layers to separate 304 square tube from corrosive medium. Seamless square tube is a useful method to prevent 304 square tube from corrosion.

就目前來說，方管-鍍鋅方管-熱鍍鋅方管-鍍鋅方管廠-鍍鋅方矩管廠家-天津鍍鋅方管廠埋在地下的燃氣管道常用的外防腐涂層主要分為五類，有三層PE復合結構，環氧樹脂粉末，無縫方矩管采用的都是鎂合金對304方管進行保護的，無縫方矩管環氧煤瀝青和PE膠帶。

At present, the commonly used external anti-corrosion coatings for buried gas pipelines of square pipe - galvanized square pipe - hot-dip galvanized square pipe - galvanized square pipe factory - galvanized square pipe manufacturer - Tianjin galvanized square pipe factory are mainly divided into five categories, including three-layer PE composite structure, epoxy resin powder, seamless square pipe, which adopts magnesium alloy to protect 304 square pipe, seamless square pipe, epoxy coal tar pitch and PE tape.

因為三層PE復合結構，環氧樹脂粉末防腐涂層性能優異，所以也是歐美國家埋地管道中的主要防腐涂層，我國人們使用都是根據耐用年限，維護費等全 面的經濟因素考慮的，所以將三層PE復合結構防腐涂層作為選擇，一般在犧牲陰極保護法中。

Because of the excellent performance of three-layer PE composite structure and epoxy resin powder anti-corrosion coating, it is also the main anti-corrosion coating in buried pipelines in Europe and America. Chinese people use it according to comprehensive economic factors such as service life and maintenance cost. Therefore, three-layer PE composite structure anti-corrosion coating is generally used in sacrificial cathodic protection method.

采用的都是鎂合金對304方管進行保護的，304方管因為會在輸出的電流過程中遭受到破壞，所以，所選用的鎂合金犧牲陽極的設計使用年限是和管道的使用年限相匹配，這樣既不會產生浪費，也不會增加維護的費用。

Magnesium alloy is used to protect the 304 square tube. Because the 304 square tube will be damaged in the process of output current, the design service life of the selected magnesium alloy sacrificial anode is matched with the service life of the pipeline, so there will be neither waste nor increase the maintenance cost.