Dimple Jacket Proof Test

[MDS N SONS]

We are fabricating a pressure vessel to Section VIII Div 1 which will have a dimple jacket. We plan to proof test per UG-101(m). It will be an embossed plate, plug welded to a plain plate. Welds are being looked at per UW-19(c)and the plain plate as a stayed surface per UG-47. We will calculate the required burst pressure per UG-101(m)(2)(-a)adjusted per UG-101(k) for max temp, to obtain the 150 PSI MAWP we need.

My question is the size of the sample for the proof test. 17-7 states not less than 5 pitches an 24" x 24", but 17-7 is concerning welding qualifications. 17-5 sends you to UG-101 but mentions the test may be part of the test in 17-7.

UG-101(m) mentions a full size sample. We are struggling with UG-101(d) which allows the proof test of similar geometry to be used. Is the 24" x 24" sample enough for the proof test if we maintain the same material specs, thicknesses and dimple spacing? If so would the proof test sample need to be rolled to the same radius as the vessel or can it be flat? Thanks in advance.

 

[r6155]

You can use flat. Note that the formula in UG-47 is for flat,like UG-34
The sample must be with the same thicknesses and materials as the original design.

Regards

 

[IdanPV]

Hi,

Stick to UW-19(c)(2) and 17-5(a) - both stated that the MAWP shall be established using proof test in accordance with UG-101(m)(2).
Both of them require 5 pitches in each direction and size of at least 600mm.

Note that for the calculation you shall use E=0.8.
For the Tensile strength, you can use UG-101(j)(3) and use an excess stock material.
My suggestion, when cutting the parts for the test cut the parts for tensile test as well. That will give you the opportunity to use excess stuck to determine the tensile strength.