ring grooves cannot have repair performed by simply skim
cutting the Hub face and deepening the groove.
API 16A Hub connections differ from flanges in that the ring
groove, face, Hub O.D., and Hub edge width, all must conform
to the exact API specified dimensions and tolerances in
order to seal and function reliably. Field measurements on
all of these dimensions require special tools and skills.
New API monogrammed equipment has experienced careful
measurement and testing by the manufacturer and only
knowledgeable persons qualified to perform dimensional
inspection on Hub connections should do so.
Any groove rework beyond polishing must include weld repair
to the Hub to provide stock for repair machining.
require weld repair to existing used Hub connected
equipment, operators should consider adding corrosion
resistant material inlay to the existing Hubs at the time of
If operators expect to
connect and disconnect Hub connection equipment and store
the equipment for any extended time, the operator would do
well to specify corrosion resistant material inlay in the
ring grooves at the time of original order.