About Magnetic Testing and Materials Testing
Author: Anirban Bhattacharya
Magnetic testing and materials testing are an integral part of industrial operations of the metallurgical segment. These are two different methods of testing namely, destructive testing and non-destructive testing.
Magnetic testing methods are generally used for examinations where non-destructive methods are to be used. These methods are used to detect faults in welds of pipelines and cracks in blades for turbines. The common techniques involved are the Magnetic Flux Leakage (MFL) and the Portable Yoke or the Alternating Current Field Measurement (ACFM) techniques.
The ACFM can be effectively applied equally in ferrous and non-ferrous materials and their alloys. The ACFM analyzes materials through their coatings. No direct contact is required. On the other hand, the MFL is a tool used for testing steel structures only. It requires the creation of a powerful magnetic field in the steel structure. The flux lines are studied so as to detect the likely pitted areas and cracks. There is an advanced version of this equipment called the Inline Inspection Tool or the MFL-ILI in which the tool travels inside the pipeline and cleans and collects the information. Other magnetic testing methods use multiple sensors to increase the resolution and hence the accuracy of the results Materials testing:
A material may suffer from a number of defects such as cracks, cavities, gas holes, slag inclusions, incomplete fusion, incomplete penetration, lack of bond, laminations, surface flaws, poor ductility, poor resistance, susceptibility to corrode, poor tensile strength, inconsistent wall thickness etc. These defects may ruin the whole production schedule.
A material testing is carried out in a metallurgical laboratory using sophisticated test equipment. The tests include metals and their alloys, both ferrous and non-ferrous, ceramics and polymers. This type of testing is destructive in nature and the results are compared with anticipated values. Similarly, materials testing could be carried out to assess the material's properties of stress, impact, flexibility, UTS, ability to wield, proof load values and hardness among others. Thus, the frame of a chopper or an aircraft could be subjected to repeated cycles of air pockets and air currents to confirm the point of failure under fatigue. A turbine blade sample could be placed under high temperature conditions to assess its resistance to creep.
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About the Author
The article is contributed by a professional article writer, having experiences of working in different industries. For further information on failure analysis and rope access please visit http://www.acuren.com/
Does radius of a solenoid affect it’s magnetic field strength?
Rank in order, from smallest to largest, the magnetic fields B1 to B3
produced by these three solenoids.
same turns same length just different radius measurements.
Thanks
no. When it reads volts, it is reading volts, nothing else. Ditto for amps or ohms.
You need a field strength meter.
You can approximate one by a large coil of wire with many turns, and reading the AC voltage across it.
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The magnetic field produced by a solenoid does not depend on the radius of the coil.
as B = (mu nought)*ni where n is the number of turns per unit length, i is current.
Thus all three solenoids will produce same magnetic field.
The magnetic energy enclosed by the volume of the solenoid will vary with radius.
Field distortions propagate at the speed of light right? Can’t measure for gravity, what about Elec/Mag Field?
Everyone loves to talk about gravitational waves, but it’s just too weak of a force and too tied up with our sense of space-time to really be measured…
So has anyone really done measurements on the propagation of large-scale changes of a straight electric/magnetic field?
In my sillyness I imagine some scientist in the pacific ocean turning some massively strong electromagnet on and off @ a predetermined frequency and some other scientist sitting in the atlantic ocean with some incredibly delicate and sensitive field indicator expecting to measure disturbances at the predetermined frequency by some time offset that hopefully makes sense given all that we know about field interaction and relativity.
Tried to find information on this through normal noob-y means (wiki, google) and failed so I ask here.
Ever hear of “radio”? How about “cell phones”, “television”, “satellites”, etc.
All of these communicate through the principle of electromagnetic “disturbances”. These are well-known and they travel at the speed of light, because that’s what they are.
The light that we see from the Sun is an electromagnetic disturbance. It just happens to be at the frequency detectable by our visual receptors.
How to measure electric and magnetic fields in a balloon flight?
I plan to do a scientific balloon flight in a standard hydrogen balloon, and I would like to include electric and magnetic measurements, as these were also done by the original balloon researchers about a century ago. But what would be the best instruments to measure these fields? Originally, electrometers were connected to two metal wires of different length to measure the electric potential between the ends of the wires by means of the electroscope. How exactly is that done, e.g. how do I get the electric potential from the electroscope reading?
As for magnetic fields, often magnetic needles were made to swing and the time they needed to swing a certain number of times was taken and compared to the value taken on the ground. Are there superior methods than this one to get the magnetic field?
Coulombs is the measurement of force particles present correct?
If I understand correctly, then I have some questions.
Can the law be used to measure magnetic fields?
Also Coulomb’s force can it measure in both alike and unlike particles? ex force from repeling or attracting?
Also what other laws are similar to coulombs?
Use instruments.
No, a coulomb is the measurement of charge. It is proportional to the number of electrons.
If you mean Coulomb’s Law, yes, it measures the force between two charges.
It does not apply to magnetic fields.
yes
Gravitational attraction is similar.
Coulomb’s law, force of attraction/repulsion
F = Q₁Q₂/(4πε₀r²)
where ε₀ = 8.8542e-12 F/m = permittivity of space (Farad/meter)
Q₁ and Q₂ are the charges in coulombs
r is separation in meters
Gravitational attraction in newtons
F = G m₁m₂/r²
G = 6.67e-11 m³/kgs²
m₁ and m₂ are the masses of the two objects in kg
r is the distance in meters between their centers (center of mass)
.
will a DC or AC multimeter read a magnetic field strength?
when it gives me a dc or ac measurement can i covert it to like newton or teslas?