It takes a lot more power to lift 2,500 pounds of steel plate than can be found in a steel or iron compass needle, that’s for sure. Magnetic materials used these days fall into four groups: Alnico, Ceramic (Ferrite), Samarium-Cobalt, and Neodymium. Each has its own characteristics, advantages and disadvantages.
Alnico magnets are made from iron alloyed primarily with aluminum, nickel, and cobalt, thus the name, though they can also include copper or titanium, and these magnets have been around since the 1930s. While not the strongest magnets when compared to rare earth magnets, they have the highest range of operating temperatures. As temperature increases, magnets begin to lose strength, and when the temperature reaches the Curie temperature for that magnetic material, they lose all magnetization and become useless as magnets until remagnetized. The Curie temperatures for Alnico magnets are the highest, in the range of 800° C and with a maximum normal operating temperature in the range of 500° C. Depending on the exact Alnico alloy, Alnico magnets can be isotropic, able to be magnetized in any direction, while others are anositropic, having a preferred direction of magnetization. They are less resistant to corrosion than the rare earth magnets, but not so much as the ferrites. Though the oldest of the four categories of magnets listed above, their combination of strength and thermal characteristics makes them still relevant today, and they are used in such areas as the manufacture of guitar pickups, electric motors, microphones, sensors, and loudspeakers.
Ceramic magnets (Ferrite magnets) were also originally developed in the 1930s, with technological advances increasing their magnetic strength to the levels we see today. They are made from iron (III) oxide mixed with other elements such as strontium, barium, manganese, nickel, or zinc, and are strong, very resistant to corrosion, retain their magnetism very well, and economical of cost. This combination of factors makes ceramic magnets the magnet of choice for applications such our Model 1057 lifting magnet, able to lift up to 2500 pounds of steel plate, as well as for magnetic sign capping with our Magna Caps. Unusually compared to other ferromagnetic materials, ferrite magnets are not conductors of electricity. They have a good operating temperature range, though with a Curie temperature in the range of 450° C not to the level of Alnico magnets. Due to the combination of cost and power, ceramic magnets see wide applications industrially in lifting and separating, and because of their lack of electrical conductivity, find use in transformers and even electromagnets to control eddy current losses. The core memory of early computers was made with ferrite cores, and ferrite particles and powder are even used in magnetic recording tape as well as in radar-absorbing stealth technology.
Neodymium magnets are the magnets people usually mean when they speak of rare earth magnets, though there are actually 17 rare earth elements, and samarium-cobalt magnets are also rare earth magnets. They have the highest strength for their size, of all the types of magnets you can buy today, which makes them the choice when power is the only consideration, but they have significant disadvantages as well. They were discovered in the 1980s independently by General Motors and by Sumitomo Special Metals and are available in several grades of strength, from N28 to N52 (the strongest). All are anisotropic, strongly having a preferred direction of magnetization and difficult to magnetize in other directions. They tend to be vulnerable to corrosion and are thus often covered with a protective coat. Neodymium magnets are very costly, and not generally suitable for high-temperature applications due to their lowish Curie temperatures, in the 300-400° C range. Even with these disadvantages however they find wide usage, in applications from electric motors and computer hard drives to magnetic bearings and loudspeakers.
Samarium-Cobalt magnets are our final class of magnets, and they, like neodymium magnets, belong to the category of rare earth magnets. Like neodymium magnets they are quite strong, though not quite so much so as the neodymium. When you add in the fact that they are also brittle, like neodymium magnets, but are even more costly, you might think that there is no reason for using them, but they do have one large advantage over neodymium, and that is the operating range of temperatures, with Curie temperatures in the range of 700-800° C, about twice as high as for neodymium.
At Magnetic Specialties, we have dealt with all of these from the ceramic magnets utilized in our Model 1037, 1037jr, and other lifting magnets, to custom-designed neodymium applications. For smaller parts-handling solutions, try our Model 790 hand magnet!
]]>Muscling around heavy steel plates becomes easy when using our lifting magnets to do the job for you. Operation is simple: just set the hoist magnet in place centered on the steel you wish to move, turn the cam release to fix the magnet in place with a firm bond, and lift with your hoist. Once the plate is in place, just turn the cam release handle to break the bond and pull the magnet away. The simple, proven technology of permanent magnets lets you go places an electromagnet would not, with the added benefit of safe operation free from possible shocks or failures due to faulty wiring.
Magnetic Specialties magnets allow safe lifting and handling of your steel plate loads, with no wires to trip on, no need to run long extension cords that might fray or come unplugged, and no possibility of a power failure or tangled power cord dropping your load. Convenient, safe, and simple. Economical, efficient, and effective. Our lifting magnets check all the boxes!
Magnets have come a long, long way since the ancient Greeks described the lodestone and today’s permanent magnets have a strength that would have been unbelievable to them, with lifting magnets such as our Model 1057, rated to handle loads of up to 2,500 pounds easily and safely. Even larger loads can be accomplished with the use of a spreader bar arrangement. Our combination of high-quality C-8 ceramic magnets and steel pole pieces channels magnetic lines of force into your steel workload for safe lifting and positioning, and the ferrite magnetic material has a working temperature of up to 250 degrees Celsius.
Yes, these really are permanent magnets! After 100 years of use, Magnetic Specialties magnets will still retain ninety-nine percent of their magnetism. Some of our hoist magnets have remained in service for over forty years, for lift after lift. They say that diamonds are forever but diamonds lift no steel.
Magnetic Specialties lifting magnets are built to last with American craftsmanship in our Portland, Oregon facility, with a sturdy, all-welded construction based on a stainless steel enclosure, and we offer free testing and evaluation of the continued serviceability of our magnets. Every magnet is tested to at least double capacity before being passed, giving you dependable lifting you can trust.
Why do our magnets work so well for you? It all comes down to the properties of steel and the way it channels magnetic flux. While magnetism can travel directly through air or space, mild steel “attracts” the magnetic lines of force and channels them through it. By our arrangement of the poles of the magnets themselves within our lifting magnets, and the steel pole pieces, we guide that magnetic flux into your steel workload by means of strong, direct contact between the surfaces of the pole pieces of the lifting magnet and the surface of your steel workload. This also means that the magnets themselves are protected from damage. When your lift is done, the simple cam release breaks the contact to allow for easy removal of the magnet.
Magnetic Specialties capitalizes on over seventy years of experience in the field, experience that includes permanent magnetic applications for industry in a wide variety of forms, from magnetic pulleys and drums that separate ferrous from non-ferrous material, to our Magna Cap line of magnetic sign capping magnets (that also make great general purpose shop magnets), from chute magnets and plate magnets to of course, our hoist magnets referenced above.
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Find out more about our complete line of lifting magnets here.
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