alan calder

8/7/2019 Alan Calder

1/46

MANUFACTURED

DISCONTINUITIES

or REAL FLAWS

-NDE APPLICATIONS

AND

CHARACTERISTICS


2/46

What Are Real Flaws?

Manufactured Discontinuities or Real Flaws areintentionally created and placed defects in critical

areas, such as weld joints, base materials, parts, etc .

Their intent is to replicate the NDE response of theactual defect


3/46

Two Fundamental Approaches

Induced Actual Creation of the flaw in acontrolled environment where its extents can be

accurately measured

Manufactured Manufacturing of an indicationthat will produce the expected NDE response


4/46

Three Types of Real Flaws

Weld or Base Material Defects

Fatigue Cracks

Alternative Flaws


5/46

Real Flaw Type 1 -

Weld/Base Material DefectsWeld defects occur during the welding process.

Some Examples of weld defects:

Slag or Tungsten Inclusion Lack of Fusion Incomplete Penetration

Porosity


6/46

Real Flaw Type 1

Weld/Base Material DefectsBase Material defects are present in the base material

of machined parts, vessels, structures, or in the raw

material itself

Lamination Single Gas Pores Cracking


7/46

Real Flaw Type 2 -

Fatigue CracksThese cracks are a result of cyclic fatiguing orloading

Thermal Fatigue

Mechanical Fatigue


8/46

Real Flaw Type 3 -

Alternative Flaws Intended to minimize base metal disturbance

Combination of traditional flaw manufacturing withmachining and PWHT

Limited customer base currently


9/46

REAL FLAWS

NDE APPLICATIONS


10/46

Who uses Real Flaws?

Some industries or groups currently benefitting from

their use are:

Commercial Nuclear Power Petrochemical Nuclear Navy Aerospace Training & Education


11/46

Who uses Real Flaws?

Some codes currently being serviced by these flaws

are:

AWS D1.1 & D1.8 ASME Sec V, VII, XI ASME BPVC CASE 2235 API-UT-1 & RP 2X


12/46

The Future

New Materials

New Defect Types

Tighter Tolerances

New Markets


13/46

REAL FLAWS

NDE CHARACTERISTICS


14/46

A36 CS Plate, 12x12 x 0.75T


15/46

A-Scan UT CalibrationPLATEBOTTOM

PLATETOP


16/46

Phased Array CalibrationSECTOR SCAN

40 - 70

A-SCAN (53)

PLATE BOTTOM

CURRENT ANGLE


17/46

Lack of FusionIncompletely fused area in the weld. Typically

between the weld and base material or in

between weld beads or passes.


18/46

Lack of Fusion(Mid-Wall)Expected UT Response

Location Approximately 1.8 or 5.3 screendivisions(conventional)

Signal Crack-like, well-defined Consistent signal as probe is skewed or moved

axially


19/46

Lack of Fusion(Mid-Wall)TOP

BOTT

OM


20/46

Lack of Fusion(Mid-Wall)Probe Skewed Left 15 Probe Skewed Right 15

GATE


21/46

Lack of Fusion(Mid-Wall)

PLATE BOTTOM

LACK OF FUSION


22/46

Slag InclusionNon-metallic byproduct of the welding process,

which becomes trapped in the weld


23/46

Slag InclusionExpected UT Response

Location Anywhere in weld volume Signal Broad, multi-peaked, singularentity

Primarily amplitude change is seenwith axial movement or skewing of probe


24/46

Slag InclusionTOP

BOTT

OM


25/46

Slag InclusionProbe Skewed Left 15 Probe Skewed Right 15


26/46

Slag Inclusion

PLATE BOTTOM

SLAG INCLUSION


27/46

PorosityEntrapped gas in solidified metal. It can be

clustered or linear(wormhole).


28/46

Porosity(Cluster)Expected UT Response

Location Any position through the volume ofthe weld

Signal Broader signal with multiple peaks andmultiple ring cycles

Axial movement or skewing of probe show aconsistent indication response


29/46

Porosity(Cluster)TOP

BOTTOM


30/46

Porosity(Cluster)Probe Skewed Left 15 Probe Skewed Right 15


31/46

Porosity(Cluster)

PLATE BOTTOM

POROSITY


32/46

Incomplete PenetrationArea where the weld does not fully penetrate

through the thickness of the weld joint..


33/46

Incomplete PenetrationExpected UT Response

Location Weld centerline, at or near 3.5 screendivisions

Signal Clean, sharp, well-defined


34/46

Incomplete PenetrationTOP

BOTTOM

TIP SIGNAL


35/46

Incomplete Penetration

TIP SIGNAL

INCOMPLETE

PENETRATION

PLATE BOTTOM


36/46

Fatigue Crack HAZ AreaBase material crack located a short distance from

the weld fusion line, in the HAZ(Heat-Affected

Zone)


37/46

FatigueCrack HAZ AreaExpected UT Response

Location At or near 3.5 screen divisions Signal Single indication with multiple ring

cycles, sometimes accompanied by pre & post-cursor indications

Axial probe movement results in increase &decrease of signal, but no character changes

Skewing of probe may show amplitude changesin signal


38/46

Fatigue Crack HAZ AreaTOP

BOTTOM


39/46

Fatigue Crack HAZ AreaProbe Skewed Left 15 Probe Skewed Right 15


40/46

Fatigue Crack HAZ Area

HAZ CRACK

PLATE BOTTOM

A-SCAN


41/46

Fatigue Crack Toe AreaBase material crack located at the toe of the weld

crown, running parallel to the weld


42/46

Fatigue Crack Toe AreaExpected UT Response

Location At or near 7th screen division Signal Similar response to HAZ crack, with

location being the differentiating factor


43/46

Fatigue Crack Toe AreaTOP

BOTTOM


44/46

Fatigue Crack Toe AreaProbe Skewed Left 15 Probe Skewed Right 15


45/46

Fatigue Crack Toe AreaTOE CRACK

PLATE BOTTOM


46/46

THANK YOU!

alan calder

Documents