MTIS Failure Investigator · metallic failure diagnosis
Active knowledge pack seed_pack_core_metals v0.2.0 has status ai_generated_draft — outputs are unverified drafts and require expert review before reliance.
Step 8 · Diagnostic run #1

Diagnosis result

A finalised, immutable run snapshot. Mode: Standard · pack mtis_met_tax_cards v0.1.0 (ai_generated_draft) · 2026-06-20 13:29

Confidence — evidence support for this mode. This is the strength of the entered evidence in support of this failure mode. It is NOT a probability, a statistical likelihood, or a finding of fact.
Back to adaptive diagnose Root-cause method →

Candidate failure modes

Thermal-mechanical fatigue

80.0/100
High

Supporting evidence present

  • Network or surface cracks (C10)
  • crack orientation related to thermal stress (C9, C13)
  • service temperature cycles (C5)

Evidence missing

  • oxide-filled cracks (Corrosion products / deposits)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination
  • Operating-condition review
  • Corrosion-product analysis (EDS/XRD)
Explain this score (raw S / K / C / M / B)

S=0.8 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Fretting fatigue cracking

80.0/100
High

Supporting evidence present

  • Dark fretting debris (C12)
  • contact scar (C12)
  • crack at contact edge (C9, C12, C13)

Evidence missing

  • multiple shallow origins (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • Loading / stress review
Explain this score (raw S / K / C / M / B)

S=0.8 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Bending fatigue

75.0/100
High

Supporting evidence present

  • Semi-elliptical surface origin (C9, C10)
  • crack front marks (C9, C10, C13)

Evidence missing

  • final overload opposite origin (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.75 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Ammonia SCC

75.0/100
High

Supporting evidence present

  • Intergranular/transgranular cracking (C13)
  • blue/green corrosion products possible (C11)

Evidence missing

  • residual stress source (Service environment)

Suggested test to raise certainty

  • Service-environment chemistry review or sampling
  • SEM fractography
  • Corrosion-product analysis (EDS/XRD)
  • Environment chemistry review
Explain this score (raw S / K / C / M / B)

S=0.75 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Polythionic acid SCC

75.0/100
High

Supporting evidence present

  • Intergranular cracking in sensitised HAZ/base metal (C13)
  • refinery shutdown history (C8)

Evidence missing

  • sulphide/acid conditions (Corrosion products / deposits)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • SEM fractography
  • Macro / visual examination
  • Corrosion-product analysis (EDS/XRD)
Explain this score (raw S / K / C / M / B)

S=0.75 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Scuffing / scoring

75.0/100
High

Supporting evidence present

  • Longitudinal score marks (C10)
  • smeared/overheated surfaces (C10)

Evidence missing

  • rapid damage onset (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.75 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Galling

73.3/100
High

Supporting evidence present

  • Severe torn surfaces (C10)
  • seizure marks (C10)
  • high friction history (C8)

Evidence missing

  • transfer lumps (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.7333 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

VHCF

66.7/100
Moderate

Supporting evidence present

  • Internal fish-eye origin (C9)
  • little surface initiation (C10)

Evidence missing

  • fine granular area (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • SEM fractography
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.6667 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Creep crack initiation/growth

66.7/100
Moderate

Supporting evidence present

  • Intergranular cracking (C13)
  • time-dependent crack extension (C9, C13)

Evidence missing

  • creep cavities ahead of crack (Microscopy / metallography)

Suggested test to raise certainty

  • Metallographic sectioning and microscopy
  • SEM fractography
  • Metallography
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.6667 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

LME

66.7/100
Moderate

Supporting evidence present

  • Intergranular or brittle crack path (C9, C13)
  • rapid cracking during contact (C12, C13)

Evidence missing

  • liquid metal residue (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • SEM fractography
  • Macro / visual examination
  • Loading / stress review
Explain this score (raw S / K / C / M / B)

S=0.6667 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Low-cycle fatigue

65.0/100
Moderate

Supporting evidence present

  • Multiple crack origins (C9, C13)
  • plastic strain marks (C10)
  • transgranular cracking (C13)
  • rapid crack growth after cyclic plasticity (C9, C13)

Evidence missing

No critical gaps.

Suggested test to raise certainty

  • Macro / visual examination
  • Loading / stress review

Contradicting: Very high cycle count with elastic stress only

Explain this score (raw S / K / C / M / B)

S=1.0 · K=1.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Wear (adhesive/abrasive)

65.0/100
Moderate

Supporting evidence present

  • Surface material loss, scoring, grooves, galling or polishing at contact surfaces (C12)
  • Wear debris in lubricant or assembly (C12)
  • Lubrication deficiency (starvation, degradation, wrong lubricant, dry running) (C8)

Evidence missing

  • Dimensional loss at contact surfaces beyond tolerance (Dimensional measurements)
  • Abrasive contamination present (sand, dust, grit) (Service environment)

Suggested test to raise certainty

  • Dimensional / wall-thickness survey
  • Service-environment chemistry review or sampling
  • Surface examination
  • Dimensional survey
  • Lubricant/debris analysis
  • Hardness
Explain this score (raw S / K / C / M / B)

S=0.65 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Fretting wear

60.0/100
Moderate

Supporting evidence present

  • Dark oxide debris (C12)
  • polished/rough contact scar (C12)

Evidence missing

  • shallow pits (Macro / visual examination)
  • stick-slip boundary (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Loading / stress review
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.6 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Plating-induced hydrogen embrittlement

60.0/100
Moderate

Supporting evidence present

  • Delayed brittle fracture after plating (C9, C10)
  • intergranular/quasi-cleavage features (C10)
  • high hardness (C14)
  • plating history (C6, C8)

Evidence missing

  • Delayed brittle fracture after plating (Coating / protection records)

Suggested test to raise certainty

  • Coating / protection system review
  • Coating system review
  • SEM fractography
  • Hardness survey
Explain this score (raw S / K / C / M / B)

S=1.0 · K=1.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Torsional shear fracture

53.3/100
Moderate

Supporting evidence present

  • Spiral fracture (C9, C10)
  • dimpled shear features (C10)

Evidence missing

  • shear lips (Macro / visual examination)
  • plastic twisting (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.5333 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

High-temperature hydrogen attack

53.3/100
Moderate

Supporting evidence present

  • Decarburised zones (C9)
  • intergranular cracking/blisters (C13)

Evidence missing

  • methane fissures (Macro / visual examination)
  • loss of strength (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Metallography
  • Macro / visual examination
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.5333 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Alpha-prime embrittlement

48.0/100
Moderate

Supporting evidence present

  • Hardness/toughness change (C14)
  • brittle fracture (C9, C10)
  • thermal exposure record (C6)

Evidence missing

  • Hardness/toughness change (Hardness)
  • phase decomposition evidence (Microscopy / metallography)

Suggested test to raise certainty

  • Hardness survey across the section
  • Metallographic sectioning and microscopy
  • Hardness survey
  • Macro / visual examination
  • Operating-condition review
  • Metallography
Explain this score (raw S / K / C / M / B)

S=0.8 · K=1.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Weld-toe fatigue

45.0/100
Moderate

Supporting evidence present

  • Crack at weld toe/root (C9, C13)
  • beach marks (C10)

Evidence missing

  • Crack at weld toe/root (Welding records)
  • lack-of-fusion or undercut as initiator (Welding records)

Suggested test to raise certainty

  • Welding record review
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.75 · K=1.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Coating cracking

45.0/100
Moderate

Supporting evidence present

  • Crack network in coating (C9, C13)
  • substrate corrosion at cracks (C11)

Evidence missing

  • Crack network in coating (Coating / protection records)
  • thermal mismatch pattern (Operating conditions)

Suggested test to raise certainty

  • Coating / protection system review
  • Operating-condition data review
  • Coating system review
  • Macro / visual examination
  • Operating-condition review
Explain this score (raw S / K / C / M / B)

S=0.75 · K=1.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Ratcheting

44.4/100
Moderate

Supporting evidence present

  • Incremental dimensional growth (C12)
  • local thinning (C11)

Evidence missing

  • ovalisation (Macro / visual examination)
  • bulging (Macro / visual examination)
  • fatigue may follow (Loading & stress)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Loading / stress review or analysis
  • Dimensional / thickness survey
  • Macro / visual examination
  • Loading / stress review
Explain this score (raw S / K / C / M / B)

S=0.4444 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Plastic collapse

41.7/100
Moderate

Supporting evidence present

  • Gross deformation before rupture (C9)

Evidence missing

  • hinge lines (Macro / visual examination)
  • collapse shape consistent with limit load (Loading & stress)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Loading / stress review or analysis
  • Macro / visual examination
  • Loading / stress review
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Intergranular brittle fracture

41.7/100
Moderate

Supporting evidence present

  • Faceted grain-boundary surface (C10)

Evidence missing

  • rock-candy morphology (Macro / visual examination)
  • grain-boundary precipitates or cavities (Microscopy / metallography)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Metallographic sectioning and microscopy
  • SEM fractography
  • Macro / visual examination
  • Metallography
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Torsional fatigue

41.7/100
Moderate

Supporting evidence present

  • Helical or 45-degree crack path (C9, C13)

Evidence missing

  • shear-mode initiation (Macro / visual examination)
  • final torsional overload zone (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Chloride SCC

41.7/100
Moderate

Supporting evidence present

  • Branched transgranular cracks in austenitic stainless steels (C13)

Evidence missing

  • chloride deposits (Corrosion products / deposits)
  • heat-transfer concentration sites (Macro / visual examination)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination of the fracture and component
  • Metallography
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Droplet impingement erosion

41.7/100
Moderate

Supporting evidence present

  • Impact pits (C7)

Evidence missing

  • leading-edge roughening (Macro / visual examination)
  • directional erosion pattern (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Loading / stress review
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Tribocorrosion

41.7/100
Moderate

Supporting evidence present

  • Wear scar with corrosion products (C11)

Evidence missing

  • repassivation damage (Macro / visual examination)
  • accelerated loss versus wear/corrosion alone (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Type II hot corrosion

41.7/100
Moderate

Supporting evidence present

  • Pitting-like hot corrosion (C11)

Evidence missing

  • sulphate deposits (Corrosion products / deposits)
  • attack at temperature/deposit-prone zones (Corrosion products / deposits)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination
  • Corrosion-product analysis (EDS/XRD)
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Nitridation / chlorination

41.7/100
Moderate

Supporting evidence present

  • Nitride/halide products (C11)

Evidence missing

  • internal attack (Macro / visual examination)
  • embrittlement or accelerated wastage (Dimensional measurements)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Dimensional / wall-thickness survey
  • Macro / visual examination
  • Dimensional / thickness survey
Explain this score (raw S / K / C / M / B)

S=0.4167 · K=1.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Corrosion (general/pitting/crevice)

34.4/100
Low

Supporting evidence present

  • General wall thinning or measurable metal loss (C11)
  • Pitting or crevice attack on surfaces (C11)

Evidence missing

  • Corrosive service environment (chlorides, acids, moisture, seawater) (Service environment)
  • Corrosion products/deposits present (rust, scale, oxide) (Corrosion products / deposits)
  • Protective coating or cathodic protection breakdown (Coating / protection records)

Suggested test to raise certainty

  • Service-environment chemistry review or sampling
  • Corrosion-product / deposit analysis (EDS / XRD)
  • Coating / protection system review
  • Corrosion product analysis
  • Dimensional/thickness survey
  • Environment chemistry
Explain this score (raw S / K / C / M / B)

S=0.4762 · K=0.6667 · C=0.0 · M=0.3333 · B=1.0

Override score:

Slurry erosion

30.0/100
Low

Supporting evidence present

  • Thinning/grooving at flow changes (C11)
  • particle impact features (C7, C10)
  • corrosion products if synergistic (C11)

Evidence missing

No critical gaps.

Suggested test to raise certainty

  • Dimensional / thickness survey
  • Loading / stress review
  • Corrosion-product analysis (EDS/XRD)

Contradicting: Stagnant corrosion under deposit without erosive flow

Explain this score (raw S / K / C / M / B)

S=1.0 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Hot tearing

30.0/100
Low

Supporting evidence present

  • Interdendritic crack surfaces (C9, C10, C13)
  • oxidised crack surfaces (C9, C10, C13)
  • location at constrained sections (C9)

Evidence missing

No critical gaps.

Suggested test to raise certainty

  • Macro / visual examination

Contradicting: Service fatigue crack with beach marks

Explain this score (raw S / K / C / M / B)

S=1.0 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Necking

29.2/100
Low

Supporting evidence present

  • cup-and-cone fracture association (C9, C10)
  • dimples if fractured (C10)

Evidence missing

  • Local area reduction (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Resonance-induced fatigue

29.2/100
Low

Supporting evidence present

  • fatigue beach marks (C10)
  • service vibration history (C5, C7, C8)

Evidence missing

  • Multiple origins at high-stress points (Loading & stress)

Suggested test to raise certainty

  • Loading / stress review or analysis
  • Loading / stress review
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Stress-oriented HIC

29.2/100
Low

Supporting evidence present

  • crack orientation stress-related (C9, C13)
  • sour-service history (C8)

Evidence missing

  • Array of small cracks linking through wall (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • Loading / stress review
  • Environment chemistry review
Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Strain-age embrittlement

29.2/100
Low

Supporting evidence present

  • brittle fracture tendency (C9, C10)
  • strain-age thermal history (C8)

Evidence missing

  • Increased yield/ductility loss (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • Operating-condition review
Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Fatigue

27.8/100
Low

Supporting evidence present

  • Beach marks (crack arrest lines) on fracture surface (C10)
  • Cyclic/vibratory/rotating service loading (C7)

Evidence missing

  • Fatigue striations visible under SEM (Fracture-surface examination (fractography))
  • Ratchet marks indicating multiple initiation sites (Fracture-surface examination (fractography))
  • Initiation at stress concentration (fillet, keyway, thread, hole, weld toe, notch) (Macro / visual examination)

Suggested test to raise certainty

  • SEM fractography of the fracture surface
  • Macro / visual examination of the fracture and component
  • SEM fractography
  • Macro examination of origin
  • Stress analysis
  • Hardness
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.6667 · C=0.0 · M=0.0 · B=1.0

Override score:

Uniform corrosion

23.3/100
Low

Supporting evidence present

  • corrosion products (C11)
  • predictable corrosion allowance consumption (C11)

Evidence missing

  • Relatively even wall loss (Dimensional measurements)
  • thickness reduction (Dimensional measurements)

Suggested test to raise certainty

  • Dimensional / wall-thickness survey
  • Dimensional / thickness survey
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.4667 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Two-body abrasive wear

23.3/100
Low

Supporting evidence present

  • cutting/ploughing marks (C10)
  • wear debris (C12)

Evidence missing

  • Parallel grooves (Macro / visual examination)
  • directionality (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.4667 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Quench cracking

22.0/100
Low

Supporting evidence present

  • Cracks at sharp corners/section changes (C10)
  • high hardness (C14)
  • no service crack-growth marks (C5, C10)

Evidence missing

  • brittle appearance (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • Hardness survey
  • Service-history review

Contradicting: Fatigue striations from service cycles

Explain this score (raw S / K / C / M / B)

S=0.7333 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Corrosion-fatigue cracking

21.7/100
Low

Supporting evidence present

  • Fatigue features with corrosion products (C10, C11)

Evidence missing

  • multiple origins at pits (Macro / visual examination)
  • reduced life versus air (Macro / visual examination)
  • branching may occur (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination

Contradicting: Dry inert service

Explain this score (raw S / K / C / M / B)

S=0.3333 · K=1.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Dynamic overload fracture

20.0/100
Low

Supporting evidence present

  • Deformation pattern aligned with impact (C9)
  • sudden overload features (C10)

Evidence missing

  • local denting (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Loading / stress review
  • Macro / visual examination

Contradicting: Service crack-growth evidence predating the impact

Explain this score (raw S / K / C / M / B)

S=0.6667 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Temper embrittlement

20.0/100
Low

Supporting evidence present

  • Intergranular brittle fracture (C9, C10)
  • service heat-treatment history (C5, C8)

Evidence missing

  • upward shift in transition temperature (Operating conditions)

Suggested test to raise certainty

  • Operating-condition data review
  • SEM fractography
  • Operating-condition review
  • Service-history review

Contradicting: Ductile fracture; no embrittling thermal history

Explain this score (raw S / K / C / M / B)

S=0.6667 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Coating delamination

20.0/100
Low

Supporting evidence present

  • interfacial fracture (C9, C10)
  • corrosion products under coating (C11)
  • poor surface profile/contamination (C10)

Evidence missing

  • Lifted coating (Coating / protection records)

Suggested test to raise certainty

  • Coating / protection system review
  • Coating system review
  • Macro / visual examination
  • Corrosion-product analysis (EDS/XRD)
Explain this score (raw S / K / C / M / B)

S=0.6667 · K=0.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Grinding burn

19.4/100
Low

Supporting evidence present

  • hardness gradient (C14)
  • surface cracks (C10)

Evidence missing

  • Temper colour (Macro / visual examination)
  • retempered/rehardened layer (Hardness)
  • residual stress (Loading & stress)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Hardness survey across the section
  • Loading / stress review or analysis
  • Macro / visual examination
  • Hardness survey
  • Loading / stress review
Explain this score (raw S / K / C / M / B)

S=0.3889 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Solidification cracking

18.0/100
Low

Supporting evidence present

  • Centreline/interdendritic weld crack (C9, C13)
  • oxidised/segregated surfaces (C10)
  • no service striations (C5)

Evidence missing

  • Centreline/interdendritic weld crack (Welding records)

Suggested test to raise certainty

  • Welding record review
  • Macro / visual examination
  • SEM fractography

Contradicting: Hydrogen cold crack in HAZ after cooling

Explain this score (raw S / K / C / M / B)

S=1.0 · K=1.0 · C=1.0 · M=1.0 · B=1.0

Override score:

Thermal bowing

17.5/100
Low

Supporting evidence present

  • distortion without cracking (C13)
  • thermal gradients in service history (C5)

Evidence missing

  • Repeatable bowing with temperature (Operating conditions)

Suggested test to raise certainty

  • Operating-condition data review
  • Operating-condition review
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Ductile overload

17.5/100
Low

Supporting evidence present

  • Dimpled (microvoid coalescence) fracture surface under SEM; cup-and-cone profile (C10)
  • Documented single overload, impact or pressure surge event (C7)

Evidence missing

  • Gross plastic deformation, necking, bending or bulging adjacent to fracture (Macro / visual examination)
  • Shear lips at fracture edges; fracture at ~45 degrees to load (Fracture-surface examination (fractography))
  • Inclusions or second-phase particles at the bases of dimples (microvoid nucleation sites) under SEM (Microscopy / metallography)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • SEM fractography of the fracture surface
  • Metallographic sectioning and microscopy
  • Visual/macro
  • SEM fractography
  • Tensile test

Contradicting: Beach marks or fatigue striations present

Explain this score (raw S / K / C / M / B)

S=0.381 · K=0.5 · C=0.5556 · M=0.0 · B=1.0

Override score:

Seam / lamination

17.5/100
Low

Supporting evidence present

  • orientation parallel to rolling direction (C6)
  • inclusion-lined surfaces (C10)

Evidence missing

  • Planar internal indication (Non-destructive testing)

Suggested test to raise certainty

  • Non-destructive testing (UT / RT / MPI / PT)
  • Non-destructive testing
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Quench/heat-treatment distortion

16.7/100
Low

Supporting evidence present

  • out-of-tolerance dimension (C12)
  • hardness/microstructure gradients (C14)

Evidence missing

  • Warping (Macro / visual examination)
  • bowing (Macro / visual examination)
  • twist (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • Metallography
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Axial fatigue

16.7/100
Low

Supporting evidence present

  • beach marks (C10)

Evidence missing

  • Planar crack growth normal to axial stress (Loading & stress)
  • final overload (Macro / visual examination)

Suggested test to raise certainty

  • Loading / stress review or analysis
  • Macro / visual examination of the fracture and component
  • Loading / stress review
  • SEM fractography
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Primary creep / secondary creep deformation

16.7/100
Low

Supporting evidence present

  • creep strain record (C6)

Evidence missing

  • Permanent elongation/sagging/bulging (Macro / visual examination)
  • grain-boundary cavities may begin (Microscopy / metallography)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Metallographic sectioning and microscopy
  • Macro / visual examination
  • Metallography
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Crevice corrosion

16.7/100
Low

Supporting evidence present

  • sharp boundary between exposed (C10)

Evidence missing

  • Attack under gasket/deposit/lap joint (Corrosion products / deposits)
  • crevice area (Macro / visual examination)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Chromium carbide sensitisation

16.7/100
Low

Supporting evidence present

  • intergranular corrosion/SCC (C11)

Evidence missing

  • Grain-boundary carbide/depleted zones (Microscopy / metallography)
  • HAZ association (Welding records)

Suggested test to raise certainty

  • Metallographic sectioning and microscopy
  • Welding record review
  • Metallography
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Subsurface rolling-contact fatigue

16.0/100
Low

Supporting evidence present

  • Subsurface origin (C9)
  • inclusion-associated crack (C9, C13)

Evidence missing

  • spall (Fracture-surface examination (fractography))
  • butterfly morphology (Fracture-surface examination (fractography))

Suggested test to raise certainty

  • SEM fractography of the fracture surface
  • Macro / visual examination
  • SEM fractography

Contradicting: Surface corrosion/wear origin only

Explain this score (raw S / K / C / M / B)

S=0.5333 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Sigma phase formation

16.0/100
Low

Supporting evidence present

  • Brittle fracture (C9, C10)
  • hardness changes (C14)

Evidence missing

  • reduced toughness (Macro / visual examination)
  • metallographic sigma phase (Microscopy / metallography)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Metallographic sectioning and microscopy
  • Macro / visual examination
  • Metallography
  • Hardness survey

Contradicting: No sigma phase in microstructure; ductile fracture

Explain this score (raw S / K / C / M / B)

S=0.5333 · K=1.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Sulfide stress cracking

15.2/100
Low

Supporting evidence present

  • high hardness/strength (C14)
  • often little corrosion loss (C11)

Evidence missing

  • Brittle cracks (Macro / visual examination)
  • H2S/sour-service exposure (Service environment)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Service-environment chemistry review or sampling
  • Macro / visual examination
  • Hardness survey
  • Environment chemistry review

Contradicting: low-strength qualified material

Explain this score (raw S / K / C / M / B)

S=0.4667 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Hydrogen embrittlement

14.3/100
Low

Supporting evidence present

  • Hydrogen source: plating, pickling, cathodic protection, H2S/sour service (C6)

Evidence missing

  • Hydrogen source: plating, pickling, cathodic protection, H2S/sour service (Service environment)
  • High-strength/high-hardness steel (susceptible grade) (Material specification)
  • Intergranular or quasi-cleavage fracture morphology (Fracture-surface examination (fractography))
  • Delayed failure under static load (hours–weeks after installation) (Service history)

Suggested test to raise certainty

  • Service-environment chemistry review or sampling
  • Material specification & certification review
  • SEM fractography of the fracture surface
  • Service-history record review
  • Fractography (intergranular)
  • Hardness
Explain this score (raw S / K / C / M / B)

S=0.2381 · K=0.5 · C=0.0 · M=0.5 · B=1.0

Override score:

Surface-initiated rolling-contact fatigue

13.3/100
Low

Supporting evidence present

  • surface cracks (C10)

Evidence missing

  • Micropitting (Macro / visual examination)
  • grey staining (Macro / visual examination)
  • shallow spalls (Fracture-surface examination (fractography))

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • SEM fractography of the fracture surface
  • Macro / visual examination
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.2667 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Bimetallic corrosion

12.5/100
Low

Supporting evidence present

  • location tied to couple (C9)

Evidence missing

  • Preferential attack of one metal near joint/contact (Loading & stress)
  • noble metal protected (Macro / visual examination)

Suggested test to raise certainty

  • Loading / stress review or analysis
  • Macro / visual examination of the fracture and component
  • Loading / stress review
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Cavitation erosion

12.5/100
Low

Supporting evidence present

  • little corrosion product initially (C11)

Evidence missing

  • Honeycomb/pitted roughness (Macro / visual examination)
  • damage at low-pressure/high turbulence zones (Loading & stress)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Loading / stress review or analysis
  • Macro / visual examination
  • Loading / stress review
  • Corrosion-product analysis (EDS/XRD)
Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Metal dusting corrosion

12.5/100
Low

Supporting evidence present

  • carburised zones (C9)

Evidence missing

  • Pits/grooves filled with carbonaceous dust (Macro / visual examination)
  • rapid local wastage (Dimensional measurements)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Dimensional / wall-thickness survey
  • Macro / visual examination
  • Dimensional / thickness survey
Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Scale/coating spallation

12.5/100
Low

Supporting evidence present

  • exposed substrate hot corrosion/oxidation (C11)

Evidence missing

  • Spalled scale patches (Fracture-surface examination (fractography))
  • repeated scale layers (Corrosion products / deposits)

Suggested test to raise certainty

  • SEM fractography of the fracture surface
  • Corrosion-product / deposit analysis (EDS / XRD)
  • SEM fractography
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Stress rupture

11.1/100
Low

Supporting evidence present

  • intergranular cracking (C13)

Evidence missing

  • Creep cavities (Microscopy / metallography)
  • necking or bulging (Macro / visual examination)
  • oxide-filled cracks (Corrosion products / deposits)

Suggested test to raise certainty

  • Metallographic sectioning and microscopy
  • Macro / visual examination of the fracture and component
  • Corrosion-product / deposit analysis (EDS / XRD)
  • Metallography
  • SEM fractography
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.2222 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Pressure burst

10.0/100
Low

Supporting evidence present

  • wall thinning if corrosion-assisted (C11)

Evidence missing

  • Fish-mouth opening (Macro / visual examination)
  • ductile tearing (Macro / visual examination)
  • hoop-stress orientation (Loading & stress)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Loading / stress review or analysis
  • Macro / visual examination
  • Loading / stress review
  • Dimensional / thickness survey
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Creep-fatigue interaction

10.0/100
Low

Supporting evidence present

  • cavities plus fatigue features (C10)

Evidence missing

  • Mixed transgranular/intergranular cracking (Fracture-surface examination (fractography))
  • oxide-filled cracks (Corrosion products / deposits)
  • dwell sensitivity (Service history)

Suggested test to raise certainty

  • SEM fractography of the fracture surface
  • Corrosion-product / deposit analysis (EDS / XRD)
  • Service-history record review
  • SEM fractography
  • Corrosion-product analysis (EDS/XRD)
  • Service-history review
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Relaxation failure

10.0/100
Low

Supporting evidence present

  • little visible cracking (C13)

Evidence missing

  • Loss of bolt preload (Loading & stress)
  • gasket leakage (Macro / visual examination)
  • relaxed spring force (Macro / visual examination)

Suggested test to raise certainty

  • Loading / stress review or analysis
  • Macro / visual examination of the fracture and component
  • Loading / stress review
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Under-deposit corrosion

10.0/100
Low

Supporting evidence present

  • chemistry gradient evidence (C14)

Evidence missing

  • Attack under scale/sludge/deposit (Corrosion products / deposits)
  • tubercles (Corrosion products / deposits)
  • pit clusters (Macro / visual examination)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
  • Chemical composition analysis
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

High-temperature sulfidation

10.0/100
Low

Supporting evidence present

  • sulphur-rich corrosion products (C11)

Evidence missing

  • Sulphide scale (Corrosion products / deposits)
  • metal loss (Dimensional measurements)
  • carburisation/sulfidation interactions possible (Macro / visual examination)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Dimensional / wall-thickness survey
  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Dimensional / thickness survey
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Graphitisation of carbon steel

10.0/100
Low

Supporting evidence present

  • service temperature history (C5, C8)

Evidence missing

  • Graphite nodules/planes (Microscopy / metallography)
  • reduced strength (Macro / visual examination)
  • intergranular/planar weakness (Fracture-surface examination (fractography))

Suggested test to raise certainty

  • Metallographic sectioning and microscopy
  • Macro / visual examination of the fracture and component
  • SEM fractography of the fracture surface
  • Metallography
  • Macro / visual examination
  • SEM fractography
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=0.0 · B=1.0

Override score:

Coating blistering

10.0/100
Low

Supporting evidence present

  • fluid/corrosion products beneath (C11)

Evidence missing

  • Dome-shaped blisters (Coating / protection records)
  • loss of adhesion (Macro / visual examination)

Suggested test to raise certainty

  • Coating / protection system review
  • Macro / visual examination of the fracture and component
  • Coating system review
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
Explain this score (raw S / K / C / M / B)

S=0.3333 · K=0.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Stress corrosion cracking

9.8/100
Low

Supporting evidence present

  • Branched cracking in metallographic section (C13)

Evidence missing

  • Susceptible alloy–environment combination present (Service environment)
  • Sustained static tensile stress incl. residual stress (welding, forming) (Loading & stress)
  • Inter- or transgranular cracking with little plastic deformation (Microscopy / metallography)

Suggested test to raise certainty

  • Service-environment chemistry review or sampling
  • Loading / stress review or analysis
  • Metallographic sectioning and microscopy
  • Metallography (branching)
  • SEM
  • Environment chemistry

Contradicting: Fully ductile dimpled fracture

Explain this score (raw S / K / C / M / B)

S=0.2381 · K=0.5 · C=0.4444 · M=0.5 · B=1.0

Override score:

Brittle fracture

9.5/100
Low

Supporting evidence present

  • Chevron (herringbone) marks pointing back to origin (C10)
  • Impact or high strain-rate loading (C7)

Evidence missing

  • Little or no plastic deformation; flat fracture normal to stress (Macro / visual examination)
  • Bright granular/crystalline or cleavage fracture surface (Fracture-surface examination (fractography))
  • Low service/ambient temperature at failure (Operating conditions)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • SEM fractography of the fracture surface
  • Operating-condition data review
  • Charpy impact
  • SEM fractography
  • Hardness

Contradicting: Dimpled ductile fracture surface

Explain this score (raw S / K / C / M / B)

S=0.2917 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Solid-particle erosion

8.7/100
Low

Supporting evidence present

  • impact craters/cutting lips (C7)
  • thinning at elbows/nozzles (C11)

Evidence missing

  • Directional wastage (Dimensional measurements)

Suggested test to raise certainty

  • Dimensional / wall-thickness survey
  • Dimensional / thickness survey
  • Loading / stress review

Contradicting: Electrochemical corrosion without particle impact pattern

Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Carbide spheroidisation

8.7/100
Low

Supporting evidence present

  • reduced hardness/strength (C14)
  • creep deformation association (C9)

Evidence missing

  • Spheroidised carbides (Microscopy / metallography)

Suggested test to raise certainty

  • Metallographic sectioning and microscopy
  • Metallography
  • Hardness survey
  • Macro / visual examination

Contradicting: As-manufactured microstructure; hardness within specification

Explain this score (raw S / K / C / M / B)

S=0.5833 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Caustic SCC

8.1/100
Low

Supporting evidence present

  • boiler/alkali service history (C5)

Evidence missing

  • Intergranular or branched cracks near caustic concentration areas (Fracture-surface examination (fractography))
  • deposits (Corrosion products / deposits)

Suggested test to raise certainty

  • SEM fractography of the fracture surface
  • Corrosion-product / deposit analysis (EDS / XRD)
  • SEM fractography
  • Corrosion-product analysis (EDS/XRD)
  • Service-history review

Contradicting: fatigue-only crack growth

Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Incomplete penetration

7.5/100
Low

Supporting evidence present

  • fatigue/fracture origin at root (C9, C10)

Evidence missing

  • Root planar indication (Non-destructive testing)
  • notch-like root defect (Macro / visual examination)

Suggested test to raise certainty

  • Non-destructive testing (UT / RT / MPI / PT)
  • Macro / visual examination of the fracture and component
  • Non-destructive testing
  • Macro / visual examination
  • Loading / stress review
Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Carburisation attack

7.0/100
Low

Supporting evidence present

  • increased hardness (C14)
  • dimensional/microstructural changes (C12)

Evidence missing

  • Carbide networks (Microscopy / metallography)
  • reduced ductility (Macro / visual examination)

Suggested test to raise certainty

  • Metallographic sectioning and microscopy
  • Macro / visual examination of the fracture and component
  • Metallography
  • Hardness survey
  • Macro / visual examination

Contradicting: Surface decarburisation or general oxidation only

Explain this score (raw S / K / C / M / B)

S=0.4667 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Rolling-contact fatigue

6.5/100
Low

Supporting evidence present

  • subsurface or surface-initiated crack networks (C9, C13)

Evidence missing

  • Pitting (Macro / visual examination)
  • spalling (Fracture-surface examination (fractography))
  • butterfly cracks (Fracture-surface examination (fractography))

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • SEM fractography of the fracture surface
  • Macro / visual examination
  • SEM fractography

Contradicting: corrosion pits alone

Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Hydrogen blistering

6.0/100
Low

Supporting evidence present

  • hydrogen/sour/corrosion history (C8, C11)

Evidence missing

  • Raised blisters (Coating / protection records)
  • internal laminations (Macro / visual examination)
  • step cracks (Macro / visual examination)

Suggested test to raise certainty

  • Coating / protection system review
  • Macro / visual examination of the fracture and component
  • Coating system review
  • Macro / visual examination
  • Environment chemistry review
Explain this score (raw S / K / C / M / B)

S=0.2 · K=0.0 · C=0.0 · M=1.0 · B=1.0

Override score:

Elastic buckling

5.4/100
Low

Supporting evidence present

  • often little fracture at initiation (C9, C10)

Evidence missing

  • Global or local out-of-plane deformation (Macro / visual examination)
  • wrinkles (Macro / visual examination)
  • lobes (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • Manufacturing record review

Contradicting: tensile fracture as primary event

Explain this score (raw S / K / C / M / B)

S=0.1667 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

General yielding

4.6/100
Low

Supporting evidence present

  • no progressive beach marks (C10)

Evidence missing

  • Permanent bend (Macro / visual examination)
  • necking (Macro / visual examination)
  • local plastic flow (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination
  • SEM fractography

Contradicting: No permanent dimensional change

Explain this score (raw S / K / C / M / B)

S=0.1429 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Lap / fold

3.8/100
Low

Supporting evidence present

  • fatigue crack from lap (C9, C13)

Evidence missing

  • Folded oxide-containing seam (Corrosion products / deposits)
  • surface-breaking linear indication (Non-destructive testing)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Non-destructive testing (UT / RT / MPI / PT)
  • Corrosion-product analysis (EDS/XRD)
  • Non-destructive testing
  • Loading / stress review

Contradicting: Open service crack with no oxide/fold interface

Explain this score (raw S / K / C / M / B)

S=0.25 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Irradiation embrittlement / swelling

2.5/100
Low

Supporting evidence present

  • service dose record (C5, C6)

Evidence missing

  • Toughness shift (Macro / visual examination)
  • hardening (Hardness)
  • swelling (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Hardness survey across the section
  • Macro / visual examination
  • Hardness survey
  • Metallography
  • Service-history review

Contradicting: No radiation service or dose record

Explain this score (raw S / K / C / M / B)

S=0.1667 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Hydrogen-assisted cold cracking

2.0/100
Low

Supporting evidence present

  • high hardness (C14)

Evidence missing

  • HAZ or weld toe/root cracks (Welding records)
  • delayed occurrence (Service history)
  • hydrogen source (Service environment)

Suggested test to raise certainty

  • Welding record review
  • Service-history record review
  • Service-environment chemistry review or sampling
  • Hardness survey
  • Service-history review
  • Environment chemistry review

Contradicting: Solidification crack morphology during hot stage; no hardness/hydrogen risk

Explain this score (raw S / K / C / M / B)

S=0.2222 · K=0.0 · C=1.0 · M=1.0 · B=1.0

Override score:

Brinelling

0.0/100
Low

Supporting evidence present

None.

Evidence missing

  • Indentations matching rolling elements or contact asperities (Loading & stress)
  • spacing related to geometry (Macro / visual examination)

Suggested test to raise certainty

  • Loading / stress review or analysis
  • Macro / visual examination of the fracture and component
  • Loading / stress review
  • Macro / visual examination

Contradicting: Fretting marks without plastic indentation

Explain this score (raw S / K / C / M / B)

S=0.0 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Stable ductile tearing

0.0/100
Low

Supporting evidence present

None.

Evidence missing

  • Stretched zone (Macro / visual examination)
  • stable tearing region (Macro / visual examination)
  • final overload zone (Macro / visual examination)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Macro / visual examination

Contradicting: No pre-existing crack; all fracture surface instantaneous

Explain this score (raw S / K / C / M / B)

S=0.0 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Atmospheric rusting/corrosion

0.0/100
Low

Supporting evidence present

None.

Evidence missing

  • Rust/oxide scale (Corrosion products / deposits)
  • preferential attack at water traps (Macro / visual examination)
  • chloride/sulphur deposits (Corrosion products / deposits)

Suggested test to raise certainty

  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination of the fracture and component
  • Corrosion-product analysis (EDS/XRD)
  • Macro / visual examination
  • Coating system review

Contradicting: Submerged-only corrosion or high-temperature dry oxidation only

Explain this score (raw S / K / C / M / B)

S=0.0 · K=0.0 · C=1.0 · M=0.0 · B=1.0

Override score:

Hydrogen-induced cracking

0.0/100
Low

Supporting evidence present

None.

Evidence missing

  • Stepwise internal cracks parallel to surface/rolling plane (Macro / visual examination)
  • blister association (Coating / protection records)
  • sulphide exposure (Corrosion products / deposits)

Suggested test to raise certainty

  • Macro / visual examination of the fracture and component
  • Coating / protection system review
  • Corrosion-product / deposit analysis (EDS / XRD)
  • Macro / visual examination
  • Coating system review
  • Corrosion-product analysis (EDS/XRD)

Contradicting: no internal cracking

Explain this score (raw S / K / C / M / B)

S=0.0 · K=0.0 · C=0.5 · M=0.0 · B=1.0

Override score:

Lack of fusion

0.0/100
Low

Supporting evidence present

None.

Evidence missing

  • Planar weld indication (Non-destructive testing)
  • unfused interface (Macro / visual examination)
  • crack/fatigue origin at weld sidewall or between passes (Welding records)

Suggested test to raise certainty

  • Non-destructive testing (UT / RT / MPI / PT)
  • Macro / visual examination of the fracture and component
  • Welding record review
  • Non-destructive testing
  • Macro / visual examination

Contradicting: Service crack through fully fused material

Explain this score (raw S / K / C / M / B)

S=0.0 · K=0.0 · C=1.0 · M=1.0 · B=1.0

Override score:

Candidate root causes

Root causeConfidenceBandVia mechanismRationale
Design issue64.0/100ModerateMECH-FM-MET-FAT-006Typical for fatigue and cyclic cracking
Design issue64.0/100ModerateMECH-FM-MET-FAT-010Typical for fatigue and cyclic cracking
Design issue60.0/100ModerateMECH-FM-MET-FAT-003Typical for fatigue and cyclic cracking
Material selection issue60.0/100ModerateMECH-FM-MET-EAC-004Typical for environmentally assisted cracking and hydrogen damage
Material selection issue60.0/100ModerateMECH-FM-MET-EAC-005Typical for environmentally assisted cracking and hydrogen damage
Maintenance/inspection issue60.0/100ModerateMECH-FM-MET-WEAR-005Typical for tribology / wear / erosion
Maintenance/inspection issue58.6/100ModerateMECH-FM-MET-WEAR-004Typical for tribology / wear / erosion
Design issue53.4/100ModerateMECH-FM-MET-FAT-013Typical for fatigue and cyclic cracking
Material selection issue53.4/100ModerateMECH-FM-MET-EAC-012Typical for environmentally assisted cracking and hydrogen damage
Unexpected service environment52.5/100ModerateMECH-FM-MET-EAC-004Typical for environmentally assisted cracking and hydrogen damage