full penetration weld

[212197]

We are carrying out full penetration weld joints in one of our project. But the customer specification does not call for carrying out volumetric NDE (i.e. RT/UT) of weld joints.So we are not carrying out RT/UT of weld joints.

But QC engineer is asking if you are not carrying out volumetric NDE, how you will ensure that the joint is full penetration weld joint?

We replied that we have done the weld configuration as per drg (i.e. root face, root gap, weld edge angle). Also back chipping is done.
All this is adequate to prove that the joint is full penetration weld joint.

Experts are requested to comment on how to ensure that the joint is full penetration weld joint without carrying out volumetric NDE.

 

[r6155]

UW-9
(b) Welding Grooves. The dimensions and shape of the
edges to be joined shall be such as to permit complete fusion
and complete joint penetration. Qualification of the
welding procedure, as required in UW-28, is acceptable
as proof that the welding groove is satisfactory

UW-26
(b) Each Manufacturer or parts Manufacturer shall be
responsible for the quality of the welding done by his organization
and shall conduct tests not only of the welding
procedure to determine its suitability to ensure welds
that will meet the required tests, but also of the welders
and welding operators to determine their ability to apply
the procedure properly

Remember the jointt Efficiency “E” that defines the thickness of pressure parts.

Regards

 

[Vikko]

In my point of view from what you said, the QC engineer is asking something unecessary, or maybe, his justification for NDT request is too weak. But he could find many other more important excuses (than the full penetration) to ask for such tests... in any case I would not perform any additional test, if it is not absolutely prescribed by the applicable standard of the design (he should at least tell from which rule of ASME VIII-1 or any other standard you are using the design, he found volumetric tests are necessary on the joint).

Full penetration welding can be established by the drawing sketch or even just by seeing the welding bevels and chamfers of the parts before welding, no need for NDT/NDE. (More than this what you can do for example is if you have visual access on the back side of the weld, you can simply verify it by visual inspection, and see if both the corners of the 2 pieces in a typical butt joint are melted together forming one part or not, no need to do any particular test).

Testing is usefull in general to ensure that there are no defects in the welded joint, for example one typical defect is lack of penetration. But there are many other possible defects. So if you want to ensure that no defects are in the joint, you shall do tests and you cannot avoid it. But there are many different type of tests that can be done (UT/RT/PT/MT/VT/ET/AT/TT/LT/ST/...) So you do not do all the possible tests on any single joint, just follow what the applicable code or design standard ask you to do: the code usually establish a set of rules, depending on many different things, like the sizes, diameters, materials, thicknesses, the joint efficiency, and so on, to know when, where and what kind of tests you shall do to comply.

 

[212197]

Thanks a lot r1655 & Vikko,

your response will help a lot.