Yes, but you have to be careful when finishing the toe area the weld bead. Fitters and welders tend to turn a grinder on edge to clan the toe of the weld and if not careful create undercut.
Don't grind the cap below flush with the base metal.
Generally speaking it is permissible to grind welds flush, but, as previously noted - excercise caution.
If you have previously carried out surface examinations such as PT or MT, they may have to be repeated.
Whereas welders and fitter generally make more money, it is common to use lower cost labor to grind finish welds. Beware!! Without proper training and policing, they will readily grind beyond flush or beyond the minimum wall.
Sec VIII Standard Hydrostatic Test UG-99 (a) A hydrostatic test shall be conducted on all vessels after:
(1) all fabrication has been completed, except for operations which could not be performed prior to the test such as weld end preparation, cosmetic grinding on the base material which does not affect the required thickness...
qcrobert,
If you're planning on grinding welds flush after hydrotest, I would get a buy in from both your AI and the customer inspector. Please heed all of the warnings above, 'cause these kind of things can go south quickly.
I always took "cosmetic grinding on the BASE material" to mean clean-up of spatter etc., taking "base material" as intended to exclude welds. I have always done all required grinding of WELDS, aesthetic or functional, BEFORE hydrotest. You may find AIs who will accept weld grinding post hydro, but for sure it's a question you'd want to ask before the fact.
"I always took "cosmetic grinding on the BASE material" to mean clean-up of spatter etc., taking "base material" as intended to exclude welds. "
Sounds logical. A defect extending upto certain depth below surface of the reinforcement can become exposed when you grind off the reinforcement. As far I understand, grinding reinforcement flush is desirable to prevent fatigue falure but should be done before any test.
