2 NDT Tests Steel

8/6/2019 2 NDT Tests Steel

1/14

The Big Five NDE Methods for

Steel structures Visual Examination (VT) Penetrant Examination (PT) Magnetic Particle Examination (MT) Ultrasonic Examination (UT)

1

Radiographic Examination (RT)

Visual Examination (VT)

inspection

Effective form of quality assurance Most extensively used NDE method

2


2/14

Visual ExaminationAdvantages Disadvantages

Quick Inexpensive Comprehensive

experience

Need clean, lightedarea

Surface onl

3

mp e oo s Measuring tools lighting cleaning

Penetrant Examination

into cracks by capillary action

Surface is cleaned, but penetrant is trappedin cracks

cracks are revealed where the enetrant

4

remains


3/14

PT Procedure

5

Penetrant ExaminationAdvantages Disadvantages

quick Inexpensive Simple equipment

afterSurface onlyRequires smooth

surface

6

asy n erpre a on


4/14

Magnetic Particle Examination

(MT)

electro-magnetization Permanent magnets

At cracks, magnetic field leaks

7

on surface are attracted to leaks providing

indication

MT Concept

8


5/14

MT Concept

9

Magnetic Particle ExaminationAdvantages Disadvantages

Economical Quick Can go over thin coating Near surface flaws

detectable

only

Electricity usuallyrequired

Arc strikes No substantial sub-surface

10

etect on Detection can be difficult

on rough surfaces


6/14

Ultrasonic Examination (UT)

A sound wave is directed through tested material Sound waves reflect at interface of different medium - -

waves Application:

Detect and evaluate flaws inside components (i.e. cracks, voids) Weld examination

11

UT ConceptDistance = Velocity Time

Back surfaceBack surface

echoecho

12

Example of longitudinal testingExample of longitudinal testing

Void echoVoid echo


7/14

Example of longitudinal testingExample of longitudinal testing

UT Concept Signal path analogous to light

reflection Use angle beam (shear

waves) Vary transducer orientation

14Similarities between reflectionsSimilarities between reflectionsof light and sound boundariesof light and sound boundaries


8/14

15

UT flaw detectorUT flaw detector

UT Field Inspection

16


9/14

Ultrasonic ExaminationAdvantages Disadvantages

Immediate result Versatile Accurate

Skilled operator

required Fillet welds

17

anardiscontinuities

18


10/14


11/14

2121

2222


12/14

Radiographic Examination

(RT) -.

Radiation is absorbed by the test piece Thick or dense areas absorb more Thin or open areas absorb less

23

Film measures passed radiation providing indication Light areas represent areas hard to penetrate Dark areas represent areas easy to penetrate

(discontinuity)

RT Concept: Detection

24


13/14

Application: Good tool in measuring general/uniform wall thickness

loss.

Good tool for locating localized corrosion. Provide actual icture (film ne ative of item/area

inspected. Qualitative results for assessment of corrosion severity

generally require supporting methods (manual UT) .

25

Radiographic ExaminationAdvantages Disadvantages

Detects surface andinternal

Planar discontinuityorientation

Provides permanent record(to scale!)

accurate

Radiation hazard (largearea must be evacuateddue to radiation concern)

Initial cost/size limitation Requires skilled operators/

26

nterpreters Must access both sides Relatively slow due to

radiation control and filmprocessing


14/14

Ima e can be viewed in real time.

27

Excellent tool for location welds under insulation. Little to no ability to locate general/uniform wall loss. Good tool for detecting localized corrosion-external only. Assessment in strictly qualitative.

2 NDT Tests Steel

Documents

Transcript of 2 NDT Tests Steel