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Magival ®
Magival® is a group of easily workable ferritic stainless steels
developed for magnetic applications where required:
• high permeability
• low coercitive force
It is produced entirely by Valbruna Stainless Steel in Vicenza
from casting to cold working. Controlled chemical analysis and
sophisticated elaboration processes allow us to produce ferritic
structures which are highly sensitive to magnetic field variations
without expensive post mechanical working annealing. Due to
the easy and fast magnetizing and faster de-magnetizing attitude,
MAGIVAL® is used to produce:
• magnetic cores
• electric valves
• electromagnetic devices
• flow regulators
• relays
Simply knowing the coercitive force hc is not always enough to
develop a plan which uses soft magnetic steel. Determinin the
hysteresis cycle and normal magnetization curves allows us to
evaluate the magnetic characteristics of the steel to be used for
electric valves magnetic core construction or magnetic devices.
In Valbruna laboratories, characterization of magnetic steels is
performed through permeameters and coercimeters.
Permeameters
Produce
hysteresis cycles and normal measurements
of magnetization of magnetic stainless steels. Using SANFORD - BENNET
allows us to perform measurements on samples or round bars,
square, flat, hexagonal and polygonal. Completely automated
are: control of parameters Br,
Hc, Bsat,
Jsat,
µmax
and elaboration of data is done by dedicated software.
Coercimeter
Is an automatic device which allows for precise measurements of
coercitive force of steel samples in any form, regular or irregular
and details which are custom made or assembled with other materials.
Heat treatment on finished products
Any mechanical working alters the magenetic properties of a material
to some extent. In any case, thanks to the particular characteristics
of Magival® ground annealed, the variation induced by mechanical
working is contained in levels so as to make it unnecessary to perfom
heat treatment on finished products.
In case of finishing status different from ground (hot rolled, cold
drawn, peeled-reeled) we reccomend, after mechanical working by
the client, annealing treatment to obtain optimum magnetic characterisitics.
Certifications
Tests are performed in accordance with the following norms:
• Permeameter
- ASTM 341
or IEC 404-4
for straight samples or bars
- ASTM 596
or IEC 404-4
for toroidal samples
• Coercimeter
- ASTM 341
or IEC 404-7
Steel is supplied with the following certifications:
• b and j normal magnetization curves
• relative magnetic permeability curves
• hysteresis cycle to saturation or to any bmax
• 1 tesla hysteresis cyles
• chemical analysis
• mechanical characteristics and/or hardness
• non destructive controls (eddy current and ultrasound)
Technical assistance
This complete certification of mechanical and magnetic characteristis
allows for creation of any magnetic device. Clients may make use
of any of the following free services:
• magnetic characterization of product
• optimization of productive process
• evaluation of influence of mechanical working on magnetic
properties
• choice of heat treatment best for product and evaluation
of influence of mechanical working on magnetic properties
• having an indication of productive processes to be used
• require a technical visit at the branch office.
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Magnetic characteristics
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JSAT
|
µmax
|
BR*
|
HC*
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|
MG1 |
=
1,6 T |
>
1000 (< Ø 16 mm)
> 700 (> Ø 16 mm) |
<
0,8 T (BR* < 80.000 gauss) |
<
240 A/m (< Ø 16 mm) (HC*< 3 Oe)
< 320 A/m (> Ø 16 mm) (HC*<
4 Oe) |
| MG2 |
= 1,6 T |
>
1200 (< Ø 16 mm)
> 800 (> Ø 16 mm) |
<
0,8 T (BR* < 80.000 gauss) |
<
200 A/m (< Ø 16 mm) (HC*< 2,5
Oe)
< 320 A/m (> Ø 16 mm) (HC*<
4 Oe) |
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MG3 |
=
1,6 T |
>
1000 (< Ø 16 mm)
> 800 (> Ø 16 mm) |
<
0,8 T (BR* < 80.000 gauss) |
<
240 A/m (< Ø 16 mm) (HC*< 3 Oe)
< 320 A/m (> Ø 16 mm) (HC*<
4 Oe) |
| MG4 |
= 1,6 T |
>
1200 (< Ø 16 mm)
> 800 (> Ø 16 mm) |
<
0,8 T (BR* < 80.000 gauss) |
<
200 A/m (< Ø 16 mm) (HC*< 2,5
Oe)
< 320 A/m (> Ø 16 mm) (HC*<
4 Oe) |
* from 1 T (or 104
gauss)
** different specifications can be agreed
upon
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Phisical characteristics
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Density
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Electrical
Resistivity
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Coefficient of
expansion
|
Modulus of elasticity
coefficient
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Curie
Temperature
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Hardness
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| Kg/dm3
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µOhm
mm |
10-6k-1
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KN/mm2
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°C
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HRB |
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MG1 |
7,59 |
600 |
11.9 |
200 |
670 |
75 ÷ 85 |
| MG2 |
7,59 |
760 |
11.9 |
200 |
660 |
80 ÷ 90 |
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MG3 |
7,8 |
650 |
12 |
225 |
670 |
80 ÷ 90 |
| MG4 |
7,78 |
760 |
12 |
225 |
660 |
80 ÷ 90 |
*** The state of all products supplied
is: ANNEALED RECTIFIED
MG1: Is the best known and most widely used
in the automobile industry as well as household appliances.
MG2: Is used in parts for magnetic devices
where high degrees of magnetic permeability and low coercitive force
is required.
MG3: Its applications are the same as for
MG1, but is used where the requirements for higher resistance to
corrosion are necessary thanks to its high content of molybdenum.
MG4: Its composition has been studied for
uses where better magnetic specifications and resistance to corrosion
are required. Such properties are obtained thanks to a low degree
of interstitial elements and a high content of molybdenum.
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