The defect formation in aluminum lost foam castings

Past research has shown that permeability pattern major source of control for metal fill and defect formation in Lost Foam Casting. This was achieved using Real Time X-Ray to view a replacement metal plate patterns and discussed in detail in REPORT NO. 527985-2004 – Project Final Report submitted by DOE CONTRACT N0. DE-FC07-99ID13840.The objective of this task was to pattern quality and consistency through 1) the identification of the root causes of permeability pattern variations within patterns and 2) implementation of procedures to control the variations. Before any laboratory evaluations to root causes of variations in permeability pattern recognition must design experiments (DOE) that was performed to confirm that indeed permeability pattern had great control in metal fill and defect formation in aluminum Lost Foam Casting.

This DOE consists of 12 patterns each with 4, 12 and 24 mm. thicknesses, high and low fusion (controlled by steaming time) and low and high permeability coating. All patterns were coated with the same coating (Perm high or low) using the same batch of coating. Permeability maps generated using the prototype pattern permeability apparatus shown in Figure 2.1.1. Coated patterns were poured using de-gassed 356 aluminum and metal fill viewed by the Real Time X-Ray. The pattern and gating arrangement shown in Figure 2.1.2. Velocities settled metal and metal front shapes of the X-Ray video. Castings were visually inspected and defects recording. Modeling of complex castings are using 3D Flow evaluated using a cluster of 16 processors to reduce computing time. The results show that the calculation time can reduce factors of 10 and 20 depending on the number of processors used. Shrinkage predictions for V6 engine blocks, engine blocks L6, 25 mm wedge plates and castings finalized. Predictions were compared to the results section castings and X-Ray on the plates and cut wedge.

Results show that the predicted location and size of the contraction match the location and size of the projection. The simulation results from the study V6 engine block in Figure 1.3.4. Note that the size and location of the contraction in the cut parts of the castings match the simulations. The simulations were performed using the metal enthalpy calculation and theoretical metal density. And was confirmed predictions of contraction similar to in-line four cylinder and six blocks. This contraction was eliminated by changing the set gating and presented in Subtask 4.1 (gating)

Scroll to Top