3.2u Mixed papers 1 (old) Flashcards
An MPI inspection on the brace of a K-node using closed wrap coils is to be conducted. Where would you place the Gauss Meter probe to verify the required
strength of 1T?
On the HAZ on the Chord side
What Material would repel external magnetic forces?
Bismuth
In simpler terms, the magnetic field generated by bismuth when it’s placed near a magnet opposes the magnet’s field, causing them to repel each other. This property of bismuth is due to the way its electrons behave in the presence of a magnetic field, resulting in the material exhibiting diamagnetic behavior.
To introduce a skin effect in a nodal weld, which terminals of a subsea MPI transformer would you connect the coils to:
AC and common
Which of the following NDT methods would be most suitable for sizing sub-surface defects in a welded joint?
Ultrasonics A-scan
Consequential poles are created due to:
Flux leakage
True or False: An AC current cannot produce a magnetic field
False
When an AC current passes through a coiled conductor, it produces what type of magnetic field?
Longitudinal magnetic field
In the formula Ipeak (ac) = 16xr÷N what does ‘N’ represent?
Number of coils
Which NDT method would not be used underwater, to detect an internal inclusion in a steel structure?
ACFM
Flux density is defined by?
The number of lines of magnetic force per unit area
The Right Hand Rule states?
The electric current is perpendicular to the magnetic field
The Hysteresis Loop is?
Flux density plotted aqainst external magnetising force
What is the result of two or more magnetic forces acting together called?
A vector field
Which of the following terms is sometimes used as the opposite of permeability?
Reluctance
A horseshoe magnet produces what type of magnetic field?
Longitudinal
True or False: Platinum is a paramagnetic material
False
Platinum is actually a diamagnetic material, not a paramagnetic one. Diamagnetic materials, like platinum, have a weak and opposite magnetic response to an applied magnetic field. This means they are slightly repelled by magnets. On the other hand, paramagnetic materials are weakly attracted to magnets, which is the opposite behavior.
ICCP systems use voltage/amperage values in which range?
30-80 volts DC/ 300-1000 amps
If a keeper plate was attached to a permanent magnet, which way would the fluxlines run through the keeper plate?
North to South
When lines of magnetic force jump the gap formed by a surface-breaking defect, it is called?
Flux leakage
The symbol used for magentising force is?
H
At the coercive point on a B/H curve, the material would:
Have zero flux density
The standard for the contents of fluorescent MPI ink states there should be?
0.1 to 0.3% by volume of ferrous particles
True or false:
Tungsten inclusions can be introduced if arcing occurs when using current flow prods
True
The typical range of settings for an MPI test using coils would be:
5 volts. 300 amps. 3 turns