Hi, I would please ask you which of the options in bold is correct (I would opt for the first):
I have been engaged in defining engineering non-destructive testing procedures employed to detect defects and gauge corrosion resistance of welds on pipelines and structures.
I have been engaged in defining engineering non-destructive testing procedures employed to detect defects and gauge corrosion resistance of welded pipelines and structures.
I have been engaged in defining engineering non-destructive testing procedures employed to detect defects and gauge corrosion resistance in welded pipelines and structures.
I have been engaged in defining engineering non-destructive testing procedures employed to detect defects and gauge corrosion resistance of welds on pipelines and structures.
I have been engaged in defining engineering non-destructive testing procedures employed to detect defects and gauge corrosion resistance of welded pipelines and structures.
I have been engaged in defining engineering non-destructive testing procedures employed to detect defects and gauge corrosion resistance in welded pipelines and structures.