PetroStreet

We had a case at our site.
During field inspection of welding works, it was found that some of the unapproved / unbranded electrodes were being used. MTCs were found to be fake and not belonging to the original company. About 20 high thickness welds were made with those electrodes.
As a solution, we decided to perform welding on a dummy piece with the same electrodes and check as welded chemical composition and to conduct a destructive testing afterwards in order to be sure about the mechanical properties.
Is this the right approach?

Your valuable inputs are appreciated.

Sounds OK to me. By destructive testing you mean " Tensile Testing" of weld?

Approach seems to be good. Take care of the following things:
1. Ensure that the sample piece must be made in full with the same unapproved electrodes.
2. As welded chemical composition must be checked very carefully. Readings shall be taken during filling once and as well as on final capping pass. Thorough chemical analysis may be made by giving a sample so that carbon % may also be seen.
3. Your inspector shall be 100% present during the sample welding activity.
4. Destructive testing shall include tensile, bend and impact (if reqd. in case of low temp. service). Get hardness readings also.

In addition to what mechcolor has written, I think it is advisable to take some strict action against the Contractor involved. Also have a check on other welding works. This type of violation does happen in construction projects and need to be addressed in a way so that it should not be repeated again.
We encountered these such problem recently and give cut out to all the weld joints made with unapproved electrodes.

Thanks all for the inputs.
Yes Nabeel, along with Tensile we would be performing bend, impact, chemical composition and micro vickers hardness tests also.