The flange sealing face is the pressure boundary at every bolted joint — and its condition directly determines the integrity of that boundary. A raised face (RF) with pitting, radial scratches, or plastic deformation from previous gasket contact, or a ring-type joint (RTJ) groove with dimensional non-conformance or surface damage, cannot form the leak-tight seal that process safety requires. Conventional visual inspection of flange faces is limited to surface-visible defects and dimensional gauging of gross non-conformance.
Raised Face (RF) Flange
Inspection
Surface Profile and Damage Assessment
3D laser scanning of the RF sealing face captures the complete surface
profile — identifying radial scratches that cross the gasket sealing zone,
pitting on the seating surface, raised areas from previous gasket adhesion or
mechanical damage, and overall face flatness deviation from the nominal
machined profile. Surface profilometry data is reported against ASME B16.5 and
ASME PCC-1 seating surface finish requirements.
Near-Surface UT Inspection for Subsurface Defects
PAUT with high-frequency, focused focal laws directed into the flange
face material detects subsurface pitting, delaminations, and manufacturing
discontinuities below the seating surface that cannot be identified by surface
inspection alone. Where a seating surface has been repeatedly machined to
restore a corroded or damaged face, residual wall thickness beneath the seating
surface is measured to confirm adequate material remains for continued service.
Ring-Type Joint (RTJ) Groove
Inspection
RTJ Groove Dimensional Verification
The RTJ groove must conform to precise dimensional tolerances — groove
width, depth, included angle, and surface finish — to achieve the seating and
sealing performance required by the applicable flange standard. 3D scanning and
precision gauging of RTJ grooves identifies dimensional non-conformance, groove
damage, and surface condition that would compromise ring gasket seating.
Groove Cracking and Fatigue Damage
RTJ grooves in high-cycle service — subject to pressure fluctuations,
temperature cycling, and repeated joint make-up — can develop fatigue cracking
at the groove root radius. PAUT with appropriate near-surface focal laws
inspects the groove geometry for root cracking and subsurface damage,
particularly at the stress concentration locations that conventional surface
methods cannot interrogate through the groove profile.
Reports include surface profile measurements and deviation from ASME
B16.5 / ASME PCC-1 requirements, 3D face condition maps, subsurface UT findings
with depth and lateral extent, RTJ groove dimensional data, and condition
classification with recommended action — accept for service, machine and
re-inspect, or replace. Reports are structured for use as inspection records in
bolted joint management systems and regulatory inspection documentation.