Seal head straight edge
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Why do ellipsoidal or other types of end caps have straight edges?
This question has already been asked in the forum; please search first before posting a new thread. Here are the reasons: 1. To eliminate stress concentration at the edges of the end cap; 2. To facilitate welding during assembly with the cylinder body
What was said on the second floor is correct; the advantage for welding lies in the ease of using butt joints and automatic welding methods.
Note: Edge stress cannot be eliminated. The main purpose is to prevent the overlap of edge stress and welding residual stress.
I think what was said upstairs is correct; it’s mainly to prevent edge stress from overlapping with welding residual stress, as well as to facilitate alignment.
The second floor, right? The third floor is about the same. One aspect is to facilitate welding, while the other is to offset the weld from high-stress areas, allowing the stress at the edges to decrease.
As a supplementary note, when the nominal diameter DN of the head is less than or equal to 2000 mm, the height of the straight edges should be 25 mm; when DN is greater than 2000 mm, the height of the straight edges should be 40 mm
To prevent the overlap of edge stress and welding residual stress
Straight edges: Avoid the accumulation of peak stress from the transition zone and welding stress from cylinder assembly
Straight-edge sections are provided to prevent the weld joint where the head meets the cylinder from overlapping with the area subject to edge stress. Not only can welding defects occur at the circumferential welds, but welding residual stresses are also inevitable; when these combine with edge stress, it has a very adverse effect on the structural integrity. Therefore, straight-edge sections are included in the heads to improve their stress conditions.