High Profile Call Girls Nagpur Isha Call 7001035870 Meet With Nagpur Escorts
ย
Surface NDT methods
1. UNIT II SURFACE NDE METHODS
Liquid Penetrant Testing - Principles, types
and properties of liquid penetrants, developers,
advantages and limitations of various methods,
Testing Procedure, Interpretation of results.
Magnetic Particle Testing- Theory of
magnetism, inspection materials Magnetisation
methods, Interpretation and evaluation of test
indications, Principles and methods of
demagnetization, Residual magnetism.
2. Liquid Penetrant Testing
The principle of liquid penetrant tests is that the
liquid penetrants are drawn into surface flaws such
as cracks or porosities by capillary action. Then the
developer material in conjunction with visual
inspection reveals the surface flaw.
Characteristics:
โข To locate cracks, porosity and other defects that
breaks the surface as a material and has enough
volume to trap and hold the penetrant material.
โข To inspect large areas very effectively and will
work on most non-porous materials.
6. STAGES/TEST PROCEDURE OF LPI
1.Surface preparation
2. Application of penetrants
3.Dwell or penetrant time
4.Removal of excess penetrant
5.Application of Developer
6.Examinaion, interpretation and evaluation
7.Post process cleaning
7. 1.SURFACE PREPARATION
The test surface should be thoroughly cleaned
and dried before the penetrant is applied by
(i) Mechanical cleaning method
(ii) Chemical cleaning method
(iii)Solvent cleaning method
8.
9.
10. 2. APPLICATION OF PENETRANTS
Penetrant is a liquid capable of wetting the entire
surface and being drawn into fine openings.
11. 3.DWELL OR PENETRANT TIME
It is the period of time from when the penetrant applied to the surface until it is
removed.
23. Florescent Penetrant:
They are usually green in color and they
contain a dye or several dyes that fluoresce when
exposed to ultraviolet radiation.
Visible Penetrant:
It contain a red dye that provides high contrast
against the white developer background.
35. DEVELOPERS
Developer is an absorbent material capable of drawing traces of
penetrants from the discontinuities back into the surface.
Characteristics of Good Developer:
55. Magnetic Particle Inspection
Magnetic particle
Testing (MPT) is used for
the testing of material which
can be easily magnetized
(Ferromagnetic materials).
This method is
capable of detecting surface
and subsurface flaws such
as cracks and inclusions.
56. Basic Principles of Magnetic Particle (MPT)
โข When a bar magnet is broken in
the center of its length, two
complete bar magnets will result.
โข If the magnet is just cracked but
not broken completely in two, a
north and south pole will form at
each edge of the crack.
โข
โข If iron particles are sprinkled on a
cracked magnet, the particles will
be attracted to the poles at the
edges of the crack
57.
58.
59. Testing Procedure/Process of MPI
Step:1 Cleaning/ Surface preparation
Step:2 Demagnetization
Step:3 Magnetizing the object
Step:4 Addition of magnetic particles
Step:5 Illumination during inspection (e.g. UV lamp)
Step:6 Interpretation
Step:7 Documentation and reporting
79. MAGNETIC FIELD ORIENTATION IN MPI
โข In MPI, the orientation of magnetic lines of
forces is important in detection of cracks or
other defects.
โข Types of Magnetic field,
โ Longitudinal Magnetic field
โ Circular Magnetic field
82. EQUIPMENT USED IN MAGNETIC PARTICLE TESTING
1. Magnetization equipment
I. Portable
a) Permanent magnets
b) Electromagnetic yokes
c) Prods
d) Portable coils
II. Stationary
2. Portable power supplies
3. Lighting equipment
a) Visible color particle
b) Fluorescent particle
