Do conical heads and cones with seams require 100% PT?
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According to GB150, if a convex head has seams, in addition to RT testing as specified in the drawings, 100% PT testing is also required. Then, for conical heads with seams, is 100% PT testing necessary for the cone portion as well? In which standard can it be reflected?
I haven’t seen any national or industry standards regarding this, but some engineering companies include such a requirement in their design documents: all joints of convex end caps that are formed by first assembling panels together must be inspected using 100% MT or PT testing
Convex heads do not include conical heads; conical heads are also subject to non-destructive testing, just like the cylinder.
Conical heads do not belong to the category of convex heads; however, for conical heads with flanges, the formation of the transition zone is similar to that of elliptical or disc heads, and therefore additional surface inspection requirements are applied to their welds. A tapered head without flanges can be treated as a cylinder.
There is a way: in the drawings, don’t specify a conical head – instead, use the term \"cone\"... Additionally, the standards for heads do include conical heads
Although 25198 is not as strict as 150, it is better not to use a conical head
As stated on the 3rd floor, the cone should meet the requirements of the cylinder (this is generally the case)
That means that for conical heads with flanges, 100% surface inspection is required for the transition section, while for cones without flanges, the requirements applicable to cylinders apply. Thank you!
I understand it this way: although the standards do not provide specific requirements for conical heads, designers can proceed with the design based on actual conditions and specify the inspection requirements.
The key design drawings don’t come with any explanations; those of us in manufacturing can only follow the standards——we’re looking for a basis for this
The original poster has a misunderstanding of the standards. Please note the phrase “assemble first, then shape”; if shaping is done first and then assembling, it is another approach ； A conical head, if without edge removal, should be considered as being formed first and then joined.