Precise detection, sizing, and quantification of HIC, SOHIC, and stepwise cracking in sour service steel test samples — providing the CLR, CTR, and CSR calculations required by NACE TM0284 and ASTM G146 with the volumetric coverage and sizing accuracy that contact UT cannot consistently deliver.
Hydrogen-induced cracking (HIC) in
sour service steel initiates internally — invisible on the surface and
inaccessible to surface NDT methods — growing as planar hydrogen blisters, step
cracks, and stress-oriented HIC (SOHIC) that progressively reduce the effective
load-bearing cross-section of the affected steel without external indication
until the damage is advanced.
Immersion ultrasonic scanning for
HIC assessment submerges the test sample in a water bath and scans it with a
focused UT beam under computer control — delivering 100% volumetric coverage of
the test section at controlled and documented sensitivity. Every laminar crack,
blister, and step crack above the detection threshold is identified, sized, and
position-reported. The resulting dataset provides the dimensional inputs
required for CLR (Crack Length Ratio), CTR (Crack Thickness Ratio), and CSR
(Crack Sensitivity Ratio) calculations per NACE TM0284 — the quantitative basis
for material accept/reject disposition.
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HIC qualification testing
for new material procurement — sour service plate and pipe
•
In-service HIC assessment
on removed samples from sour service pressure vessels and piping
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Weld HAZ hydrogen damage
assessment for SOHIC susceptibility evaluation
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Material requalification
following exposure to excursion conditions beyond original HIC design limits
•
HIC assessment as part of
fitness-for-service evaluation per API 579
•
Vendor and mill
qualification inspection for sour service materials — upstream, midstream, and
refining
•
NACE TM0284 — Evaluation of
Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking
— primary standard governing HIC test methodology and CLR/CTR/CSR acceptance
•
ASTM G146 — Standard
Practice for Evaluation of Disbonding of Bimetallic Stainless Alloy/Steel Plate
•
ISO 17025 — Laboratory
accreditation requirements — applicable to all scanning and measurement
operations
•
API 579 / ASME FFS-1 —
Fitness-for-service assessment including HIC damage morphology evaluation
•
NACE MR0175 / ISO 15156 —
Materials for use in H2S-containing environments — sour service material
qualification context