Welding of A-36 and A516 Gr 70 1

[ukmet]

As I observed on almost all vessels manufactured in our vicinity on ASME Sec VIII Div. 1, A-36 and A-516 Gr.70 are no welded directly on pressure part. e.g, as for lifting eye (A-36) not welded with shell but a pad is welded with shell. Same is for saddles or some internal baffle plates. What could be the reason? What role does CE (carbon equivalent) have in all this scenario?

 

[fegenbush]

Many manufacturers do not keep Mill Test Reports (MTR) for A36 material. Without the material traceability, the material cannot be welded to the pressure boundary. By putting a pad of traceable material and welding to that instead, it is not necessary to trace the material for appurtenances like saddles or lifting lugs.

Carbon equivalent doesn't really play a role unless you consider the traceability to be proof that the material is weldable to ASME Section VIII Div 1.

 

[metengr]

Lifting lugs and saddles are not considered pressure retaining material or components. Therefore, all you need to do is to prove the material is weldable by Code simply by qualifying a weld procedure.

 

[JStephen]

The items in question may be to distribute load and reduce stresses, not to separate materials.

 

[ukmet]

fegenbush can you further elaborate your last sentence

metengr as your respective opinion, A-36 and SA-516 Gr 70 will not qualify a welding procedure as the difference in strengths? and what do you say about the point made by Jstephen?

 

[innovation2]

Both of the materials you list can be welded to the pressure boundary but you need to have an MTR. I specify SA-36 flat bar all the time for vacuum rings and SA-516 Gr70 is an excellent PVQ steel. I use it all the time for pressure boundaries and lifting lugs. SA-36 is typically not used in pressure boundaries but is found in all kinds of structural shapes (flat bar, round bar, plate, etc.) You will run into MDMT issues using SA-36 when thicker since it is a curve A material, it is exempt to -20F up to 1/2" thick.

 

[metengr]

metengr as your respective opinion, A-36 and SA-516 Gr 70 will not qualify a welding procedure as the difference in strengths? and what do you say about the point made by Jstephen?

ukmet - I am not sure about the first statement regarding SA 36 and SA 516, both are considered weldable and belong to the same P-No grouping under Section IX. The second part of your statement, I agree with JStephen.

 

[GenB]

Nothing is wrong with A36 material plate used as shell or heads it was a good choice in the pass, better materials came along and now A36 is not used as press.part The preferred A516 happens to be near the cost of A36 and with greater advantage.