6.4 - NDT-Magnetic Particle Examination
6.4 - NDT-Magnetic Particle Examination
6.4 - NDT-Magnetic Particle Examination
No. 1
CONTENT PART 2
Planning of NDT
Content of test procedures Evaluation of results Recording of tests and results Applicable NDT Rules
No. 2
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Test Methods
No. 5
Contrast
Test surface and mag. particles together Test should provide high contrast.Appropriate particle colours should be chosen, e.g. black, red, grey. With fluorescent particles, max. fluorescence brightness should be selected. Remark: Thin surface coating (background paint white) together with black mag. Particles provide very good contrast.
poor contrast Strong background disturbance
FST 2002 Welding &NDT
No. 6
No. 7
Scope of application:
Welds, gear-tooth
No. 8
No. 9
A.C magnetic field skin-effect, penetration small. Flaw depth max. 2-3 mm with f=50 hZ
FST 2002 Welding &NDT
D.C Magnetic field entire cross section magnetized, greater depth penetration. Flaw depth max.5-8 mm
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No. 11
Yoke Magnetisation
a: b: c: d: e: f: Soft iron core Magnetic field lines Magnetic coil Flux indication Stray flux Defect
No. 12
Magnetisation Direction
No. 13
Standard Equipment
No. 14
MT of a circumferential weld.
FST 2002 Welding &NDT
No. 15
The right hand rule define the relation between curent, magnetic induction and the direction of the magnetic field lines.
FST 2002 Welding &NDT
No. 16
Direct Fluxing
No. 17
Magnetisation by prods
FST 2002 Welding &NDT
No. 18
No. 19
Coil Magnetisation
No. 20
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No. 22
Induction Fluxing
No. 23
Testing Accessories
Indication capability of the testing fluid Defect recognition Suspension evaluation After a setting time of 30 minutes the required concentration must be obtained.
No. 24
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No. 29
Defects Indication
Surface flaws Subsurface defects
No. 30
Irrelevant Indications
Development of stray-flux with strong magnetization
Irrelevant Indications
No. 31
No. 32
Evaluation of Discontinuities