Bonded Particle Filter - Pyrotek

2. DEPENDABLE METAL CLEANLINESS WITHOUT PROBLEMS
DEMANDS DEPENDABLE FILTER MEDIA
2.1 WHAT FILTERING DOES FOR METAL QUALITY
When effective, filtration substantially improves product unifor-
mity. Figure 1a and 1b show the difference between a filtered and
an unfiltered aluminium foil product.
Figure 1a.
Unfiltered aluminium
foil product metal
at 350X.
Figure 1b.
Foil alloy filtered
through 10 grit
Multicast
MC-6 filter.
Magnification 350X.
Filtering the molten metal results in significantly increased fluidity,
which improves castability and helps to prolong mold life.
Since inclusions, or hard spots, are minimised or eliminated, the
metal is easier to form or machine and tool wear is reduced.
With fewer casting defects, your yield and productivity are higher,
as is overall product quality.
Mechanical properties (tensile, yield, fatigue, creep and rupture
strength) can often be improved with filtration, but elongation
or ductility is especially sensitive to metal cleanliness, i.e. low
inclusion levels achieved with filtration means higher ductility. For
example, in extrusion billet casting, as shown in figure 2, the
percentage of elongation can be greatly increased, even doubled in
some cases.
Improved surface finish results from inclusion removal, important
for bright trim stock, cast wheels, or for any other surface finishing
operations (anodizing, painting and plating). Filtration also reduces
the rate of rejection and rework due to pinholes, linear defects or
tear-out in foil and sheet product production.
Figure 2.
Effect of filtration on
short transverse
elongation of 7079-T6.