http://fluxtrol.com Composite Materials for Magnetic Field Control in EPM

1. Composite Materials for Magnetic Field
Control in EM Processing of Materials
V. Nemkov, R. Ruffini (Fluxtrol Inc., USA)
A. Kolesnichenko (Net Shape Cast, USA)

2. Effects of Magnetic Flux Controllers
• Field Pattern Control
• Better Power Utilization in
the Part (mainly in heating
processes)
• Coil Efficiency Improvement
• Coil Power Factor
Improvement
• Reduced Coil Current
Demand
• Loss Reduction in Power
Supplying Circuitry Effect of magnetic flux concentrator
made of Fluxtrol A
• Shielding

3. Materials for Magnetic Flux Control
Available materials belong to three
major groups:
• Soft Magnetic Composites (SMC)
or Magnetodielectrics (MD)
• Laminations
• Ferrites
Fluxtrol Inc. produces 3 primary
MD materials:
• Fluxtrol A
• Fluxtrol 50
• Ferrotron 559 H

4. Primary Fluxtrol Products
Note: frequency ranges and resistivity values are only for reference

5. Magnetic Properties of Fluxtrol Products
Compared to laminations and Flux Density vs Magnetic Field Strength
ferrites, Fluxtrol materials are 14000
12000
almost linear.
Flux Density, Gs
10000
Fluxtrol A
8000
Fluxtrol A material can support 6000
Fluxtrol 50
Ferrotron 559 H
permeability above 50 at high 4000
2000
magnetic loading (flux density 0
0 50 100 150 200
up to 14000 Gs), which is Field Strength, A/cm
important for high power and
Permeability vs Flux Density
low frequency applications.
125
Relatively low permeability of 100
Permeability
Ferrotron 559
MDM compared to laminations 75
Fluxtrol 50
50
does not influence their Fluxtrol A
25
performance in non-closed 0
magnetic circuits. 0 3000 6000
Flux Density, Gs
9000 12000

6. Comparison of Laminations
and MDM Properties
Characteristics Laminations Ferrotron/Fluxtrol
Frequency, kHz up to 20 kHz Any
Effective saturation, T 1.5 – 1.6 1.2 – 1.5
Initial permeability Above 1000 18 - 63
Max permeability Around 5000 20 - 120
Permeability grades No 4 grades
Anisotropy Very strong Low to Middle
Temperature resistance, C Probably 300 – 400 C Long – 250 C
Performance in 3D field Very bad Good
Complex geometry Difficult Easy
Installation Laborious Easy
Cooling Difficult Easy – many methods
In-field adjustment Difficult Easy
Use as construction part Problematic Good

7. Fluxtrol Material Blocks for Large Installations
Fluxtrol MDM for magnetic flux concentration and shielding. Self-gluing film
insulation may be applied to the blocks if required. Largest plates at present
time are 6” x 8.5” x 2”

8. Copper Tubes with Matching Netshape
LRM Concentrators
Advantages:
1. More effective copper
and Fluxtrol cooling
2. Higher mechanical
strength
3. Minimized
manufacturing costs
4. Possibility to work
effectively in 3D
magnetic fields

9. Selected Material Processing Technologies
Frequency Power Magnetic core material
Technology
range, range, kW Existing Proposed
Lams + MDM in
Induction melting 50 -10000 Hz 50 -10000 Air or Lams
3D area
Cold-crucible melting of
500 – 5000 Hz 50 - 2000 Air MDM shunts
metals
EM pouring control 50 – 150 kHz 25 – 100 Ferrite MDM
Vacuum or controlled MDM or MDM +
50-3000 100 -10000 No or lams
atmosphere furnaces Lams
Liquid coating wiping 100-200 kHz 25-50 Lams or air MDM
Semi-levitation and
50 – 10000 Hz 50 - 500 Air MDM
levitation
Pulse treatment in
1-2 Hz 100 - 200 Lams Lams + MDM
casting
Ferrite or
EFG Crystal growth 10-30 kHz 10 - 30 MDM
MDM
Monocrystal growth 10-500 kHz 10 - 30 Air MDM

10. Magnetic Control in
Cold Crucible Melting Furnace
With No controller With Fluxtrol controller
Advantages:
• Improvement of coil efficiency and power factor
• Reduction of losses in the furnace chamber and other
components
• Possibility to use smaller chamber

11. Melting Inductor for Glove Box Environment
Induction coil for melting of radioactive
materials in protective atmosphere
Example of shielding effect and
efficiency improvement
Fluxtrol A shields on the side and Fluxtrol
bottom coil surfaces allowed to: plates
•Strongly reduce losses in the
chamber walls and bottom plate
•Increase the furnace volume in Glove Box walls
the same chamber
•Increase coil efficiency from 23 to Fluxtrol plates
63% due to reduced losses in
chamber walls, bottom plate and
in the coil Molten metal
Magnetic field lines and color map of
power density in a shielded coil

12. Shielding in Furnaces with Special Atmosphere
Due to the magnetic field
shielding it is possible:
• reduce the furnace size
or
increase the furnace
loading
• improve efficiency and
power factor of the
inductors, especially for
the bottom ones
• Fluxtrol Inc. has very good
experience in such designs

13. Possible Combinations of Lams and MDM
Due to machinability, ability to work in 3D areas and serve as structural
components, MDM may be effectively used in combination with laminations
3D area
Use of MDM in combination with MDM inserts in magnetic core for gradient
laminations in 3D areas of shunts field formation in pulse magnetic device for
steel stirring in continuous slab casting

14. Magnetic “Wiper” Concept
Electrodynamic forces created by magnetic field help to “blow out” excess of
coating material (Zn or other) from the surface of wire (left) or strip (right).
Required frequency is usually high (up to 200 kHz) and MDM material is the
only choice for magnetic material