Added value of G.AL® plates in comparison to rolled plates

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Differences in grain structure in Rolled Plates vs. G.AL® Cast Plates

Grain structure of G.AL® Cast Plates:

The structure is non directional, as cast.

The mechanical values are the same in all directions.

Grain structure of Rolled Plates:

The structure is in the direction of rolling process.

The mechanical values depend on the grain direction.

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T

W

L

Forming direction affecting properties

Rolled plates:Very great affection- resulting in residual stresses and uneven grain texture between the length

(longitudinal), width (transverse) and thickness.

G.AL® Cast plates:Because no work is applied after the casting there is hardly any residual stress but a homogeneous

micro structure throughout the whole plate.

Affection of the direction & magnitude of residual stresses and grain texture due to rolling

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Differences between Rolled Plates and G.AL® Aluminium Cast Plates

Mechanical values depend on grain direction

Rolled Plates

Very large directional strength differentials

Due to the rolling process the structure has -in the longitudinal direction of rolling- elongated

grains.

ImpactDue to the big difference in length, width and

thickness of the grain the mechanical values will vary considerably.

G.AL® Cast Plates

No directional strength differentials

Because the microstructure of the rolled ingot is not changed in plates by the sawing no

directional properties are existing.

ImpactNo big variation in mechanical properties due to

homogeneous grain sizes.

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Differences between Rolled Plates and G.AL® Aluminium Cast Plates

Residual Stresses

Rolled Plates

very high

Forming and thermal treatment inducing high stresses and tensions into the

material.

Impact

High probability of deformation before and after machining.

G.AL® - Cast Plates

hardly existing

Impact

Hardly any deformation before or after machining

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Test of residual stresses

Change from the flat „x“

(bent)

Material Change „x“

Al – Rolled Plate EN AW 7075 → 2,55 mm

Al – Rolled Plate EN AW 5083 → 1,20 mm

Al – Cast Plate G.AL® C330 → 0,65 mm

Al – Cast Plate G.AL® C250 → 0,25 mm

Differences between Rolled Plates and G.AL® Aluminium Cast Plates

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Advantages of G.AL® Aluminium Cast Plates

• no directional related mechanical properties • extremely low internal stresses• very small drop in core strength• very good flatness (G.AL – Precision Plate)• very good parallelism (G.AL – Precision Plate)• tight thickness tolerances (G.AL – Precision Plate)• very good availability• availability up to 1.060 mm / 41.7“