As most ventilation pipes are thin-walled products, warpage and deformation will occur in the process of production and use. So what is the reason for this phenomenon?

通風管道變形的原因主要有以下四點：

The main causes of ventilation duct deformation are as follows:

1、鎂水泥在自然養護條件下其體積是一個連續膨脹過程，其線膨脹率為0.1-0.2%，體積膨脹率約為1%。

1. Under natural curing conditions, the volume of magnesium cement is a continuous expansion process, with linear expansion rate of 0.1-0.2% and volume expansion rate of about 1%.

2、菱鎂礦在服燒過程中不可避免地產生局部過燒，使一部分MgO呈死燒狀態，過燒的MgO水化過程很慢，當已形成強度的水泥石中的MgO再遇水進行水化時，生成Mg(OH)2，體積膨脹120%。

2. During the service burning process of magnesite, it is inevitable to produce local overburning, resulting in a part of MgO in a dead burning state. The hydration process of overburned MgO is very slow. When the MgO in the cement stone with formed strength is hydrated again with water, Mg (OH) 2 is generated, with a volume expansion of 120%.

3、輕燒氧化鎂中游離CaO水化時體積膨脹90%，而鹵片中存在著SO42-，當Ca(OH)2轉化成石膏時，固體體積將增加2倍以上，導致制品變形，這也是限制輕燒氧化鎂中游離CaO含量、鹵片中SO42-含量的原因。

3. The volume of free CaO in lightly burned magnesia expands by 90% during hydration, while there is SO42 - in halogen tablets. When Ca (OH) 2 is converted into gypsum, the solid volume will increase by more than twice, resulting in product deformation, which is also the reason for limiting the content of free CaO in lightly burned magnesia and the content of SO42 - in halogen tablets.

4、MgO-Mg-C12-H2O系統水化過程是一個強烈的放熱反應過程，而生產的管道體積又大，若環境溫度較高，則反應升溫過程，板材本體溫度過高，反應不充分，造成較大的結晶應力和熱膨脹應力，使制品體積膨脹。

4. The hydration process of mgo-mg-c12-h2o system is a strong exothermic reaction process, and the volume of the produced pipeline is large. If the ambient temperature is high, the reaction temperature will rise. The plate body temperature is too high and the reaction is insufficient, resulting in large crystallization stress and thermal expansion stress, resulting in the volume expansion of the product.

以上就是通風管道的主要變形原因，了解這些變形原因可以幫助我們更好的解決問題，只要及時解決，是不會影響正常的工作的

The above are the main deformation reasons of the ventilation duct. Understanding these deformation reasons can help us better solve the problem. As long as it is solved in time, it will not affect the normal work