During the pressure test with a casing at 12 kilograms, the steel pipe inside collapsed
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The inner tube is made of 304 material with dimensions of 377*6, while the outer tube is a carbon steel tube with dimensions of 480*10. The pressure test for the interlayer was conducted at 12 kilograms. The 377*6 steel tube showed local bulging; I’m not sure as to the reason for this. Please help analyze it!
If it’s a local issue, then it’s a quality problem. Also, for conditions like these, it is advisable to inquire about the external pressure resistance parameters of this pipe material, for reference.
The poster had better calculate it according to GB150.3
Because your tube is relatively long and lacks reinforcing rings in the middle, this results in instability under external pressure. I just simulated the strength calculation of the inner tube as you suggested, and the results show that external pressure instability occurs when the tube length exceeds 980.
When testing the casing for pressure, pressure should be applied to the inner tube simultaneously to prevent it from becoming unstable and deforming.
It seems to be a matter of the design choice regarding the wall thickness of the inner tube. Choosing a wall thickness for the inner tube that can withstand internal pressure is fine under normal circumstances; however, the issue of external pressure was not taken into account
Can welding a support ring at the boss to reinforce it solve this problem? ?
So what level should this pressure be at? Are there any regulatory requirements? Is it determined by the design?
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