Permanent magnetisation

Is this a test, and are these trick questions?

No True/False?

I do not believe soft iron bars make good 'permanent' magnets.

If they do then I would do #4 directly to #3. (Especially if long time=permanent)

All of them can produce magnetic field to magnetize the soft iron.

and 234 can saturate the soft iron, if the turns of the coil is more enough, it can also do.

But when you stop the current, the soft iron will has no magetic.

Steel is another things.

Review your any middle school textbook you will understand it.

I don't know about the material (whether it can acquire magnetism and retain it) but we were taught in school that magnets were produced with very large coils and short, high-energy, DC pulses. I can't remember whether it was just one pulse or several though.

"And why?"

If you need your magnet in a hurry, do #2 only.

If you don't need it for awhile, do #1 for a couple of weeks then do #3 for a week or so.

Soft Iron (Fe, I guess,) is NOT a good magnetizing material, and rarely used due to low remnant magnetism properties. Non-rare earth material Hard irons are used (Ceramic magnets) . What do you really want to know? or is it a middle school quiz?

Wangito

a soft iron bar has a very low remnant magnetism. Which ever method you use if the generated magnetic field is strong enough and has a time length according to the magnetic circuit (considering the nergy to put in the magnetic circuit to reach full field strenght) the full magnetization is done. If you have a bar as soon as the field diappears the bar "works" witha big gap between the poles so that a demagnetization occurs. The reverse characteristic leeds to a veri small B and thus even it later the gap is reduced the initial field strength is not reached. This is the reason if AlNiCo or steel magnets are used the circuit is magnetized with a pulse curent much more important than the used in function but during a short time (to avoid thermal overload in assemlied position with working gaps). It is not necessary to do it with SaCo or FeB magnets which have a different reverse behaviour.

you can't make soft iron in to permanent by using any of abow method it can magnetize temperary magnetic field it may hold resedual magnetizition but it is too less. for permanent magnet you should another material lime cobalt ferried ndfeb, samerium cobalt any may more depending upon how much flux you required most probabaly there are very few people who have facility to measure magnetic property. like Bhmax, Br, Jhc and ihc I AM ONE OF THEM

What kind of equipment you use? Home made or supplied by a company?

I was confronted with the problem in the design of valves actuators. What I noticed is that usually only the so called relays irons have a neglectable hytheresis. In thesolenoid design very often are used low carbon steels and they have a small but real coercitive force. This is the reason why many times a cooper or brass washer is used to avoid a too important remanat force.

None of the above (provided it is a soft iron core)

Snakers

... 5) Stroke it with a magnet?

I love these thread posters!

They ask a question, usually a stupid one, and than .... Nothing!. not even an ooops or thanks for your time.

I usually block them to avoid further waste of time.

Wangito.