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Pipe Layout of Elbows and How to Select the Threaded Bolt Material of Elbow Connection

Bent pipe is actually a kind of pipe, but it is curved, not straight, but we can use its bending advantage to do corresponding application operations. In many cases, because the pipeline is curved, it is more flexible to transport liquid. So how should this type of pipeline be arranged?


1. When laying the pipeline in the trench, if the foundation of other materials is not specified in the design, it should be laid on the undisturbed soil. After the pipeline is installed, the pads used for laying the pipeline should be removed in time.

2. When the pipeline crosses the highway, a casing should be installed. The inner diameter of the casing should be at least 150 mm larger than the outer diameter of the pipe. If there is a joint in the casing, the elbow can only be crossed after passing the pressure test.

3. When the pipe section is buried, it should be bent naturally according to the terrain, and a fixed pier should be set at the end of the straight pipe section to prevent the deformation pressure from being transmitted to other original parts and causing damage.

4. When the bent pipe is laid underground, the thickness of the soil on the top of the pipe should meet the following requirements: when buried under a roadway, it should not be less than 1m; when buried under a non-driving road, it should not be less than 0.6m; when buried under a paddy field, it should not Less than 0.8m.


In fact, there are many ways to lay pipes for bent pipes. You must choose a suitable pipe layout method according to different terrain, temperature and surrounding environment, and check some details after pipe layout.


The selection of elbow material should have certain hardness and corrosion resistance, because it will determine the overall quality and performance of the pipeline. When connecting, bolts are often used in a certain project, but due to the influence of materials, the bolt material must be better The material of the upper pipe, then how to choose the material of the connecting bolt?


1. It is not suitable to use when the temperature is too high, because the solid stainless steel thread is easy to deform under high temperature. Although it does not rust, if the thread seam is dirty, it is easy to cause the thread to deform when bending the pipe bolt.

2. If the temperature exceeds the temperature of the material: -196℃ to 400℃, the high temperature type should be selected if the temperature exceeds the range. If the temperature is lower than 500℃, 35CrMo can also be used. Normal temperature can be used. High temperature may cause leakage.

3. Among the stainless steel bolts, 304 and 316 are low-strength bolts, which must be determined according to the strength of the elbow. When selecting bolts, not only the temperature but also the working pressure must be considered.


The material of the elbow connecting bolt must first be able to withstand the harsh environment, and then its performance must be determined according to the performance of the pipeline, and the appropriate bolt material must be selected to improve the construction quality.