1. Improve production by reducing cycle time through cooling channel. 2. Enhancement of mechanical properties. 3. Validation of Experiment with Simulation. 4. Avoid die soldering.

1. Department of Foundry Technology
National Institute of Foundry and Forge
Technology
Directional Solidification In GDC Dies Through Cooling And Heating Design
In
Aluminum Die Casting
Guided By:
Dr. Kamlesh Kumar Singh
Professor, Department of Foundry Technology
Submitted By:
Mr. Anirudh Kumar
(FFT, FF16M13)
Guided by:
Dr. TVL Narasimha Rao
Vice President, R&D, TVS Sundaram
Clayton Limited
A Project Report
on

2. Objective
1. Improve production by reducing cycle time through cooling channel.
2. Enhancement of mechanical properties.
3. Validation of Experiment with Simulation.
4. Avoid die soldering.

3. Literature Review
Author Findings
1. Feurer et al.
He proposed an equation related to solidification time and secondary
dendritic arm spacing
λf = 7.5(Mtf)0.39
M is defined as coarsening parameter with the value for Aluminium
alloys usually in the range of 1-10
λf is secondary dendritic arm spacing in micrometre
tf id solidification time in sec
2. Kang et al.
He proposed the post solidification intensive riser cooling method
(PSIRC). Risers are cooled by forced air or water mist from its top
surface at the moment that the solidification of a casting is finished.
3. Grugel et al.
He said that although primary dendrite spacing is constant during a
steady-state solidification process, SDAS is notably modified along
the primary arms. Such a behaviour can be explained on the basis of
a coarsening process of the dendrite arms during the solidification.
4. Whisler and Kattamis He analysed the coarsening phenomenon in dendritic growth.

4. Authors Findings
5. Rapiejko et al.
He proposed that cooling of mold using mist is similar to alloy
addition. The effect is same on microstructure. The microstructure is
refined under on the conditions.
6. Heusler and Schneider
He investigated the influence of alloying elements on the eutectic
temperature and the eutectic depression as essential thing for
assessing the quality of a modification treatment by means of
thermal analysis.

5. Methodology

6. Experimental Setup
Different arrangement for cooling :
Without cooling
Air water cooling
channels
Air cooling channel
Water cooling channel
Air cooling channel

7. Heat treatment
The T6 has been used for the heat treatment of the following component:
T6 is a artificial aging process and cycle of the process is as follows-
Temperature (°C) Time (hrs.)
Solutionizing 520 12
Quenching Water (65-100 ºC)
Aging 220 16

8. Results
Alloy composition:
The chemical composition is determined using Optical Emission Spectroscopy (OES) for the alloy C355.0
Alloy Si Fe Cu Mn Mg Ni Cr Ti Sr OT Al
Min 4.5 - 1.0 - 0.4 - - 0.0015 0.02 - -
OES data
4.76 0.134 1.282 0.0189 0.482 0.0058 0.0018 0.0653 0.0261 0.03 93.17
Max 5.50 0.20 1.50 0.10 0.60 0.050 0.050 0.20 0.050 0.10 -

9. Results (Contd..)
A. Microstructure observations:
The basic microstructure of the alloys consists of primary Al dendrite with eutectic Si particles distributed
between the α-Al dendrites.
λf = 7.5(Mtf)0.39
M is defined as coarsening parameter with the value for Aluminium alloys usually in the range of 1-10
λf is secondary dendritic arm spacing in micrometre
tf id solidification time in sec
Without cooling Air cooling channel
Air water cooling
channels
The rate of cooling affects the spacing by controlling the time for diffusion.

10. B. Secondary Dendritic Arm Analysis (SDAS)
The solidification time is calculated using experimental SDAS values.
Sample
Simulation,
SDAS(µm)
Experimental,
SDAS(µm)
Solidification
time (sec)
No
Cooling
22.40 17.38 8.59
Air
Cooling
21.37 16.68 7.74
Air-
Water
Cooling
20.13 10.61 2.43

11. 0
5
10
15
20
25
No cooling Compressed air
cooling
Air water cooling
SDAS(µm)
Simulation SDAS versus Experimental SDAS
Simulation, SDAS(µm) Experimental, SDAS(µm)
The graph shows the variation in SDAS values

12. C. Effect of cooling on tensile properties
Fine grain structure means greater grain boundary area and thus it produces hindrance to the dislocation
movement and thus resulting in pile-up dislocations which increases the ductility.
3
3.2
3.4
3.6
3.8
4
4.2
4.4
160
180
200
220
240
260
280
300
No cooling Compressed air
cooling
Air water cooling
%ELongation
YS,UTS(MPa)
Tensile properties

13. E. Effect of cooling on Hardness
1. The refined microstructure contains more dendritic α-Al phase that improved the hardness of the C355.0
alloy.
2. The refined microstructure has more number of grain boundaries that hinder the motion of dislocation result
in increase in hardness.
0
20
40
60
80
100
120
No Cooling Compressed air
cooling
Air water cooling
Hardness(HBN)
Hardness (HBN)
No cooling 71-77 HBN 74 HBN
Compressed air cooling 71-78 HBN 75 HBN
Air-water cooling 96-102 HBN 98 HBN
Mean

14. Radiography
The results show that the porosity like shrinkages and gas entrapment is minimum up to the required level.
Without cooling Air cooling channel Air water cooling
channels

15. Cycle time
The cycle time reduced by 14.28 %using compressed air cooling and 33.33 % using the air-water
internal cooling in comparison with no cooling.
Without cooling Air cooling channel
Air water cooling
channels
210 sec 180 sec 140 sec

16. Table Productivity benefit analysis
Without cooling With air-water cooling
Solidification time (sec) 210 140
Total time (sec) 400 330
Casting/hrs. 9 12
Casting/day (22 hrs.) 198 264
Completion (in days) 10 7

17. Conclusion
1. For diffusive transformations, faster the cooling rate, finer the grains.
2.The hardness and yield strength increases with decreasing SDAS, that is, it increases when the
cooling rate increases. The refinement of SDAS also hinders dislocation motion causing an increase
in hardness.
3. It is assumed that better agreement between the experimental and simulation results could be
achieved by changing the boundary conditions and/or testing the other mathematical models available
in the literature.
4. The Radiography shows the minimum level porosity in all casting that has been examined.
5. The cycle time reduced up to 33.33% using air water cooling method.
6. The time taken to produce 2000 castings is now reduced to7 days from 10 days.

18. Scope of work
1. Production may increase by dual cavity dies.
2. Circumferential cooling channels around the castings which can give uniform thermal balancing.
3. Reduce runner volume by half instead of full volume which can increase yield.
4. Tilt pouring in compressor housing to reduce turbulence and minimize blow hole rejection.
5. Improving the sensitivity of the mathematical modelling to reach to the desired result.

19. References
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21. Thank you….