F.O.M.T. S.p.A Successfully Cast First RecycAL Component Produced Entirely From Recycled Material

02 June 2016

Silvia Lombardo

Brunel university used the high shear process (HSP) + sedimentation developed by RecycAl to reduce the concentration of Fe in scrap aluminium. The processed material was then cast by F.O.M.T into an exhaust bracket used on high-end sports cars. The material was chemically analysed before the HSP + sedimentation process and after casting, the results in Table 1 show the RecycAl process has successfully reduced the Fe content of the scrap material from 1.09 to 0.6wt% which is within the specification for the casting alloy 0.8wt%.

Table 1: The composition in wt% of the as-received scrap material and HSP + sedimentation processed material used to produce the AlSi9Cu1 casting alloy.

Material

Fe

Si

Mg

Mn

Cu

Zn

Scrap

1.09

8.86

0.28

1.04

0.95

0.12

Cast Component (After HSP + sedimentation process)

0.607

8.672

0.257

0.47

0.924

0.06

Specification

0.8

8.3-9.7

0.25-0.65

0.15-0.55

0.8-1.3

0.8

*single figures are maxima.

How the Component is Cast:

The mould was painted with a coating specific for gravity die casting composed of refractory powders. The alloy was melted at 700°C in an electric crucible furnace in order to avoid contamination and to grant the best quality of the alloy. A new crucible was used for the RecycAl project to avoid the presence of residual contamination such as dust and especially Fe, which may be present in other alloys used in the foundry. The 700°C melt is then poured into a dried and preheated mould (T=250°C) to create the casting, as shown in Figures 1-2.

Figure 1: Photograph of the electric crucible furnace
Figure 1: Photograph of the electric crucible furnace
Figure 2: Casting of the exhaust bracket
Figure 2: Casting of the exhaust bracket

Quality Checks:
In addition to chemical analysis F.O.M.T routinely carry out tests to control the quality of their products. These include Brinell hardness testing, the TEST STRAUBE PFEIFFER (Reduced Pressure Test), to measure the density of the material, and Non-Destructive Testing (NDT), using X-Rays to ensure there is not cracking or porosity in the cast component.

  • Hardness :

The results of Brinell hardness tests on the as-cast component are shown in Table 2, these values are found to be within the required specification.

Table 2: Brinell hardness of the RecycAl material before and after casting.

Material

Hardness
HB

Before Casting

60

After Casting

70.5

Specification

60-70
  • Density:

The density of the RecycAl alloy was found to be 2.6 g/cm3, which is high compared to typical material received by F.O.M.T.  which has a density of 2.3-2.4 g/cm3. The high density of the RecycAl material is a benefit of the HSP and means the melt does not need to be degassed prior to casting.

NDT: Nondestructive Test

X-Rays of the component are shown in Figure 3.  No defects were found in the component confirming the integrity of the component.

Figure 3: X-Ray images showing the most susceptible region of the component is free from porosity and cracking
Figure 3: X-Ray images showing the most susceptible region of the component is free from porosity and cracking
Photograph of the first cast components produced using recycled material using HSP + sedimentation process developed by RecycAl
Photograph of the first cast components produced using recycled material using HSP + sedimentation process developed by RecycAl

Summary:

  • The RecycAl project has successfully reduced the Fe content of scrap material to meet the specification of a high quality casting alloy AlSi9Cu1.
  • The RecycAl alloy was very castable and did not need flux, grain refiners or melt degassing required by some other casting alloys used by F.O.M.T
  • The components produced passed all quality tests usually applied by F.O.M.T.

This is the first time a high quality cast component has been produced from scrap material using an industrially scalable process.