With the progress of technology, people's requirements for the quality of HVAC engineering are correspondingly improved, and the requirements for the cleanliness of ventilation pipeline engineering and the saving of equipment and materials are also gradually improved; The common duct materials of ventilation duct engineering mainly include galvanized stainless steel duct, stainless steel duct and composite stainless steel duct. Let's take a brief look:

不銹鋼風管質量較好，適用性強，但價 格高。目前市場上較廣的不銹鋼風管是鍍鋅板的。鍍鋅板不銹鋼風管，基本是不銹鋼不銹鋼風管的特性，但是價 格相對只有不銹鋼風管的三分之二甚更低。

The quality of stainless steel air duct is good, the applicability is strong, but the price is high. At present, the stainless steel air duct widely used in the market is galvanized sheet. Galvanized stainless steel duct is basically the characteristics of stainless steel duct, but the price is only two-thirds or even lower than that of stainless steel duct.

不銹鋼風管主要是在風管鐵皮上鍍上一層鋅，對鐵皮起到保護的作用。鋅鍍層經鈍化處理、染色或涂覆護光劑后，能顯著提高其防護性和裝飾性。

The stainless steel air duct is mainly plated with a layer of zinc on the iron sheet of the air duct to protect the iron sheet. The protective and decorative properties of zinc coating can be significantly improved after passivation, dyeing or coating with light protecting agent.

復合不銹鋼風管一般應用在外界環境較為普通，對風管要求不太高的場所。由于鐵皮容易在各種環境下發生化學反應，造成腐蝕、生銹。而鋅在干燥的空氣中幾乎不發生變化。通風管道工程在潮濕的空氣中，鋅表面會生成致密的堿式碳酸鋅膜。

Composite stainless steel air duct is generally used in the place where the external environment is common and the requirements for air duct are not too high. Because the iron sheet is easy to have chemical reaction in various environments, causing corrosion and rust. Zinc is almost unchanged in dry air. Dense basic zinc carbonate film will be formed on the surface of zinc in humid air.

在濟南通風管道加工工程施工時選擇的通風管是可以用白鐵制作的，通風風管分圓型和矩形兩種，可根據用戶的不一樣需求出產各種形狀、各種規格型號的通風管道。

In the construction of Jinan ventilation pipe processing project, the selected ventilation pipe can be made of white iron. The ventilation pipe can be divided into round type and rectangular type. According to the different needs of users, various shapes, specifications and models of ventilation pipes can be produced.

白鐵做通風管道的方形彎頭容易些，先畫出扇形，把雄的咬縫做好后量下2條曲線的長，和方管的另一邊，就成2塊曲面料的尺寸，當然不要忘加咬縫余量，如做大的方管，可先在地上放扇形，各條線盡可能放長，畫好后覆上白鐵皮拓樣就比較方便，也省料。在實踐中公式意義不大，有時需要求證放樣的精度會用一點。建議買本怎樣畫展開圖的書看。

It's easier to make square elbow of ventilation duct with white iron. First, draw a fan. After the male seam is finished, measure the length of the two curves and the other side of the square tube to form the size of two curved fabrics. Of course, don't forget to add the seam allowance. For example, for large square tube, first put a fan on the ground, and each line should be as long as possible. After drawing, it's more convenient to cover with white iron sheet. In practice, the formula is of little significance. Sometimes it is necessary to verify the accuracy of lofting. It is suggested to buy a book on how to draw unfolded drawings.

白鐵之所以備用做通風管道，與它自身優異的性質是分不開的，因為白鐵表面含有鋅層，所以管道的性質比較穩定，可以防止油水的侵蝕，從而保護管道的質量，而且白鐵是不會生銹的，所以美觀性也很好，白鐵表面比較光滑，作為管道使用，表面的雜質會比較少，在餐廳使用可以保證餐廳的美觀性，而且表面也不會有油污的殘留物，所以不會影響餐廳的美觀性。而且白鐵的價 格比較便宜，質量較輕，安裝的時候比較簡單。

The reason why white iron can be used as ventilation pipe is inseparable from its excellent properties. Because the surface of white iron contains zinc layer, the property of the pipe is relatively stable, which can prevent the erosion of oil and water, so as to protect the quality of the pipe. Moreover, white iron will not rust, so its beauty is also very good. The surface of white iron is relatively smooth, and there will be less impurities on the surface when it is used as a pipe, In the restaurant can ensure the beauty of the restaurant, and the surface will not have oily residue, so it will not affect the beauty of the restaurant. Moreover, the price of white iron is relatively cheap, the quality is relatively light, and the installation is relatively simple.