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Lifting Magnets - Product Info

Selecting the best suitable model of permanent lifting magnets

Armstrong LiftMagTM is designed for high quality lifting magnets; however, it does not mean any model is suitable for your application.    Please take the following criteria into consideration during your production evaluations.
1) ALL NL-B series lifting magnets can ONLY lift thick metals.  They are not ideal for thin metal plates.

2) A large dimensional metal sheet cannot be lifted by only one single lifting magnets even if the sheet is light in weight.  The large metal sheet must be lifted by two or more lifting magnets connected by a spreader beam.
3) NL-B lifting magnets work only belew 60oC.

4) NL-B lifting magents do not work under water.

5) The actual lift value are greatly effected by the thickness, surface conditions, size, carbon composition and working temperature of the work load to be lifted.

Lifting capacities for different thickness of flat sheet metals

Thickness (mm) NL-330B NL-660B NL-1320B NL-2200B NL-4400B
60 100% 100% 100% 100% 100%
55 100% 100% 100% 100% 100%
50 100% 100% 100% 100% 95%
45 100% 100% 100% 100% 90%
40 100% 100% 100% 100% 85%
35 100% 100% 100% 90% 75%
30 100% 100% 100% 80% 60%
25 100% 100% 90% 70% 55%
20 100% 90% 75% 60% 45%
15 100% 70% 60% 50% NOT work
10 70% 50% 40% NOT work NOT work
5 NOT work NOT work NOT work NOT work NOT work

The surface conditions of the load
The air gap between the load and the lifting magnet may be produced by rough, dirty or painted, and consequently the lifting force would be significantly decreased.
Air gap = 0, 100% of the rated lifting value. Example: flat, clean and smooth surface
Air gap = 0.1mm, 90% of the rated lifting value. Example: surface with small amount of dust
Air gap = 0.3mm, 80% of the rated lifting value. Example: rusty surface
Air gap = 0.5mm, 70% of the rated lifting value. Example: heavy rusty or painted surface
Air gap = 0.8mm, 50% of the rated lifting value. Example: uneven surface or surface with burrs

The higher alloy content in the load material, the lower the holding force
Low carbon steel: 100%
Middle carbon steel: 85%
High carbon steel: 70%
Cast iron: 50%

Case study
The work load is a 1m x 1m x 10cm low carbon flat sheet metal with dirty and rough surface and weighs 780kg.  Which NL-B lifting magnet can be used for the lifting job?
780kg/100% (low carbon)/80% (metal surface condition)/100% (metal plate thickness) = 975kg
Thus, NL-2200B can be used to lift such plate and ensure maximum safety and reliability.