Precautions for flexible metal hose and the passivation film formed

Next, we will focus on several important precautions for the flexible metal hose. Only when we understand these precautions can we use flexible metal hoses safely. Secondly, let us finally understand what is the use of the oxide film formed on the surface of the flexible metal hose.

Here is the content list:

l Precautions for flexible metal hose

l The flexible metal hose oxide film

 

 

Precautions for flexible metal hose

1. When choosing a metal flexible metal hose, please choose a metal flexible metal hose with a loose flange at one end as far as possible for ease of installation.

2. The surface of the metal flexible metal hose should be protected during electric welding at the construction site to prevent welding slag and arc ignition from burning the metal flexible metal hose.

3. Distorted installation of the metal flexible metal hose is strictly prohibited.

4. There should be no bending along the root of the metal flexible metal hose.

5. The medium through which the flexible metal hose passes must not be corrosive to the flexible metal hose material, and the chloride ion content in the medium should be ≤25PPM

6. Strictly follow the correct installation method of flexible metal hose.

7. Mechanical damage to the flange sealing surface of the flexible metal hose is strictly prohibited.

 

 

The flexible metal hose oxide film

 The metal of the flexible metal hose reacts with oxygen in the atmosphere to form an oxide film on the surface. The iron oxide formed by the metal of flexible metal hose on ordinary carbon steel continues to oxidize, which causes the rust of flexible metal hose to expand continuously, and finally forms holes in the flexible metal hose. Paint or oxidation-resistant metals (such as zinc, nickel, and chromium) can be used for electroplating to ensure the carbon steel surface of the flexible metal hose. If the protective layer of the flexible metal hose is damaged, the steel below will begin to rust.

The corrosion resistance of stainless steel flexible metal hose depends on the content of chromium. When chromium is added to 10.5%, the atmospheric corrosion resistance of flexible metal hose steel will increase significantly, but when the chromium content is higher, the corrosion resistance can still be improved.The reason is that when the steel of the flexible metal hose is alloyed with chromium, the type of oxide on the surface of the flexible metal hose is changed to a surface oxide similar to that formed on pure chromium metal. The tightly adhered chromium-rich oxide of flexible metal hose protects the surface and prevents further oxidation. This kind of oxide layer is extremely thin, and the natural luster of the stainless steel surface can be seen through the flexible metal hose, which gives the stainless steel flexible metal hose a unique surface. Moreover, if the surface layer is damaged, the exposed steel surface of the flexible metal hose will react with the atmosphere to repair itself, re-form this "passivation film" and continue to play a protective role.

If you have any questions about the precautions of flexible metal hoses and Exhaust Flexible Pipe, please call Wuxi Xishan Huanyu Metal Hose Co., Ltd., we are very happy to answer your questions.