Rheometal - Techno rheocoulée : Rapid S Process

Rheometal est une start-up suèdoise qui a developpé le Rapid S Process, une nouvelle technologie de production de matière semi_solid par voie rhéocoulée.


Principe - Lay-out of Rapid S Process

Principe
The Rapid S process is a semi-solid casting process, meaning:

1. The melt is partly solidified into a consistency of small round grains surrounded by melt.
2: This structure is created by a rapid undercooling in combination with the shearing of the melt.
3: The Rapid S slurry becomes thixotropic. The shear force required to deform a thixotropic slurry is very low, resulting in a more accurate filling of the mold.
4: A semi-solid slurry is usually 100 degrees C cooler than a traditional melt.
Its thixotropic behaviour results in a laminar metal flow, which reduces gas and shrinkage porosity.

General benefits
35% reduced cycle time
30-50% reduced locking force
Porosity elimination


Chantier pilote (suède)

Additional benefits
Less interruptions due to lower tool stress (higher utility of the casting cell)
Less manual trimming work on the components due to low tool wear and tear
Less tool management and verification costs
More alloys can be used enabling more functionality of the component
Less scrap from heat treatment due to absence of gas porosity
The slurry is formed without any additives or special alloys


Comparaison microstructure HPDC (sous pression traditionnelle) et Rapid S (rhéocasting)

source :  Rheometal

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Octobre 2008