Not in all cases.
Depends what job you're on Kev, and to what standards the job is getting done to.
For example - Offshore drilling - The Chief Engineer on a rig/drillship would be where the buck stops - but in practice he would be leaving the QC side up to the welder himself to ensure the work is up to standard and all welding procedures followed.
On offshore construction jobs on a production platform, a certain percentage of work would be done by the platform's Q.C. dept - all depending on what is being done.
On onshore jobs - like down at Wilton etc - yes inspection would be done by a QC department.
I understand all of that perfectly well my good friend.
In all instances, the welder isn’t ultimately responsible for the completed work, it’s someone above and you’ve highlighted quite succinctly that differing organisations manage delegated responsibility differently.