Qualify welders

[Thuhuongengineer]

Hi everybody,
Do we need to WPS for qualify welders. if any can you show me where in ASME or AWS statement it.
example, I qualify duplex welders but i can use material Carbon Steel. it mean WPS follow wrong, Pl Clarify.

 

[nickelkid]

It may help if you can clarify what you are doing…
In general, with BPV or B31 work all welding is required to have qualified procedures and a welder qualified to each procedure he is performing. I hope that helps with your duplex/ carbon steel question.

 

[LittleInch]

You really need to have a welding engineer / inspector assist you as it dpeends which welding code you use. Some have fairly wide ranges of materials , sizes and wall thickness which a particualr Weld Procedure Specification (WPS) is applicalble for, others less so. My limited knowledge of Duplex welding is that it requires an inert gas (argon) type of welding and requires high quality welders, but whether you could use a piece of C Stl in place of duplex but a WPS which is OK for duplex I don't know. Ask a specialist, but you do need to tell him which code you are working to.

In general your WPS then needs to be tested by undergoing various NDT and destructive tests to "prove" the WPS ina test, the WPQT. These tests are then approved by the relevant welding inspector from the client or your own internal inspector, again to what ever criteria it says on your welding code (B31.3, ASME IX etc). There is sometimes a time limt on the approval of the WPS Whichever welder did the weld is then automatically approved for that procedure.

Other welders then need to do a more simple test to that procedure, using either a test piece or their first production weld. That weld in then inspected by NDT by the approved welding inspector and if he passes, then he is also approved and on it goes.

This is what B31.3 says is required in general as part 328.1 and I would imagine other design codes say simialr things
" Each employer is responsible for the welding done
by the personnel of his/her organization and, except as provided in paras. 328.2.2 and 328.2.3, shall conduct the
tests required to qualify welding procedures, and to qualify and as necessary requalify welders and welding
operators.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[Thuhuongengineer]

it mean this question "CAN WE QUALIFY WELDER WITHOUT WPS". I can qualify welders duplex with material Carbon Steel but F-Number of consumable is Duplex. So Will i apply WPS-Carbon steel or WPS-Duplex.

 

[nickelkid]

Thuhuongengineer, without a WPS how would you be able to establish the minimum requirements for an acceptable weld to qualify the welder’s work? I am still a bit confused with your situation, but LittleInch elaborated on typical code requirements well. If you are not able to grasp it "have a welding engineer / inspector assist you."

 

[gtaw]

The welder is required to follow a WPS applicable to the qualification being taken. In other words, if the welder is welding carbon steel pipe with a F6 filler metal, the WPS should be for welding a P1 to a P1 with F6 filler metal.

Just because ASME Section IX permits certain practices such as substituting carbon steel in place of the duplex stainless pipe, it doesn't mean that it is a good idea.

Just about any welder that has welded carbon steel, austenitic stainless steel, or nickel based alloys will tell you they do not weld the same. Their molten weld pools have different characteristics. ASME Section IX apparently doesn't recognize the differences, but that isn't surprising. The people sitting on the committee are unlikely to spend much time behind a welding helmet. That statement isn't intended to be a swipe against the code committee members, it is a simple fact that most of the committee members are engineers that have different concerns from the welder tat is responsible for making the actual weld.

The purpose of welder qualification is to assess the welder's ability to deposit sound weld. No more, no less, but the welder deserves the right to follow a WPS that has been proven to produce acceptable results.

Best regards - Al