Causes of lateral cracks in elbows
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Following the direction of the elbow, a through-crack occurred at the exact center of the side surface of the elbow itself; however, the crack was only present on this side as shown in the diagram, while the other side remained intact. This kind of problem has occurred 3 times; after each replacement of the elbow, it can only function properly for about 2 years. Operating temperature: 80–430°C, pressure: below 0.2 MPa, material: 20#. Could everyone help figure out what the reason is?
This post was last edited by CHANGBAISHI on 2019-11-28 07:30. If it’s not the thickness reduction at the cracks, it’s likely due to stress factors. Consider using those elbows with a \"larger\" R-value, or try elbows with a greater thickness; if there is wear, it might be related to impurities in the medium. For reference.
Excuse me, on the first floor, 1: Based on this situation, what examinations and assessments have you carried out? 2. Are the pipe fitting quality documents in line with the order requirements? 3 Is the direction of the pipelines before and after this section related to the location of the crack? What makes medium 4 special is that a low pressure does not mean a slow flow rate, nor does it determine the direction of the fluid’s flow. 5 is indeed demanding; a 2-year operational life is sufficient. It is also possible to avoid analyzing the reasons: thicken the fittings and increase the radius of curvature (do not use 1.5); the photos appear blurry
The maximum temperature for 20 steel is 450 degrees. Up to 480 degrees, for 2 years. Excellent quality
When a large range of temperature changes is encountered, stress levels are high, leading to deformation and potentially cracking. What is the straight length of the pipeline? Is there a U-shaped bend or expansion joint for buffering in the middle?
The temperature is too high and the temperature difference is significant; moreover, the elbow should be thicker than the thickness of the pipe, which is normal for steam pipelines.
Try switching to another pipe fitting supplier; for reference only
This post was last edited by Lù Xíng Tiān Xià on 2019-12-10 08:34. A detailed stress analysis should be conducted on this piping system. Even after multiple replacements, the same problem persists; it might be due to excessive stress or improper pipeline setup.