Thinning issue of the deviation between the thickness of the small end of the long-neck butt-weld flange of the container and the wall thickness of the cylinder body
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For DN400, PN16 long-neck butt-welded flanges, the wall thickness of the smaller end is 12 mm, while the wall thickness of the cylinder body is 10 mm. Is it necessary to thin the smaller end of the flange during butt welding? The information I read states that the inner and outer diameters of the small end and the cylinder body must be identical, but the container flange specifies that the wall thickness should be 10 mm or less; it is sufficient if the deviation in wall thickness between the two is less than 0.25 times the wall thickness and also less than 3 mm. How should I decide which requirement to follow?
Check the standard specifications; there are requirements regarding the minimum thickness of the cylinder corresponding to the flange. If it is too thin, the height of the flange needs to be increased
As for the difference in wall thickness between the two, there is a transition on the surface of the weld at the outer bevel of the flange; there is no need to thin it out
Okay, thank you. But is excessive stress concentration at the welds a significant issue?
There is no need to give too much consideration to stress concentration issues in this case
A 2mm deviation allows for skipping thinning; a groove can be made directly, and the weld will cover it.
The connection between the container flange and the cylinder is always made to ensure that the inner diameter remains the same
The inner diameters are the same, while the outer diameters differ slightly; seamless tubes were used, not rolled ones
It’s impossible to do surfacing; without the right processes, it’s simply pointless
It’s not necessary; according to the design requirements, the fittings can be thicker than the pipes.