Sealing connection and use method of high pressure flange

Flange Supplier-GNEE

There are three types of high-pressure flange sealing surfaces: flat sealing surface, suitable for situations where the pressure is not high and the medium is clean; concave and convex sealing surfaces, suitable for situations where the pressure is slightly higher; tongue-and-groove sealing surfaces, suitable for flammable, toxic, Situations with high medium and high pressure. The contact width between the high-pressure flange gasket and the sealing surface is very narrow (line contact), and the processing finish of the sealing surface and gasket is high. Common integral flanges include flat welding flanges and butt welding flanges. Ordinary rubber gaskets are suitable for occasions where the temperature is lower than 120°C; asbestos rubber gaskets are suitable for situations where the water vapor temperature is lower than 450°C, the oil temperature is lower than 350°C, and the pressure is lower than 5MPa. For general corrosiveness Medium, commonly used acid-resistant asbestos board.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

High-pressure flange connection is a detachable connection. According to the connected parts, it can be divided into container flange and pipe flange. According to the structural type, there are integral flanges, loop flanges and threaded flanges. In high-pressure equipment and pipelines, lens-shaped or other-shaped metal gaskets made of copper, aluminum, No. 10 steel, and stainless steel are used. The high-pressure flange has poor rigidity and is suitable for situations where the pressure p≤4MPa; the high-pressure flange, also known as the high-neck flange, has greater rigidity and is suitable for situations where the pressure and temperature are higher. High-pressure flange gasket is a ring made of material that can produce plastic deformation and has corresponding strength.

When processing flanges, we first need to understand that such a component itself may have corresponding defects during the welding process. If the welding defects of stainless steel flanges are serious, they are basically processed by hand. Mechanically polished, this polishing method is used to compensate. Relatively speaking, it may produce a series of polishing marks, which may cause more or less uneven surface, thus directly affecting the appearance of the entire equipment.

The grinding and polishing of the flange may be uneven during processing. In this way, during a series of pickling and passivation processes, it is difficult to achieve a more uniform treatment effect for workpieces with a relatively large area. Therefore, if it cannot If this effect is achieved, it will definitely take a lot of time during the processing. Relatively speaking, the material consumption for some auxiliary materials is also very high.

There is also a problem faced during the processing. There may be some scratches on the flange. These scratches are very difficult to remove. Therefore, during the overall passivation, under the conditions of corrosive media, there will often be A series of chemical corrosion occurs, resulting in some rust.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

So, once these problems occur during flange processing, how should we solve them? First of all, we must pay attention when selecting materials. We must choose different materials according to different situations, and then process them in the correct way.

As long as we understand various industries today, people will find that in such industries, we still need to use some related equipment, especially the connection between shafts. , but how to complete such a connection, you need to use parts such as flanges at this time, so that the current connection between the pipe ends can be well realized.

It can be said that such parts can be well used for the connection between some pipe ends, or for the connection between two devices, and have become connection parts used in many industries. It is precisely because of the emergence of such spare parts that people now do not have to worry about connection problems when connecting related devices.

The connection between high-pressure flange and pipeline is to first insert the pipe into the inner hole of the flange to the appropriate position, and then lap weld. Stainless steel flange is a type of flat welding flange. So, what should we pay attention to when using stainless steel flange? The staff of the flange manufacturer will introduce to you the precautions for using flanges.

1. The hardened American standard flange of chromium stainless steel flat welding flange pipe fittings after welding is larger and prone to cracks. If the same type of chromium stainless steel electrode (G202, G207) is used for welding, preheating above 300°C and slow cooling at about 700°C after welding are required. If the weldment cannot undergo post-weld heat treatment, stainless steel flat welding flange pipe fitting electrodes (A107, A207) should be used.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. When welding stainless steel flat welding flange pipe fittings, carbides will precipitate due to repeated heating, reducing the durability and mechanical properties.

3. In order to prevent eye-to-eye corrosion due to heating of the flange cover, the welding current should not be too large, which is about 20% less than that of carbon steel electrodes. The arc should not be too long, and the interlayers will cool quickly. A narrow weld bead is preferred.

4. The welding rod should be kept dry when used. The titanium-calcium type should be dried at 150°C for 1 hour, and the low-a hydrogen type should be dried at 200-250°C for 1 hour (cannot be dried multiple times, otherwise the coating will easily crack and peel) to prevent The coating of the welding rod is stuck with oil and other dirt, so as not to increase the carbon content of the weld and affect the quality of the weldment.