The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case...
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Transcript of The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case...
![Page 1: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/1.jpg)
The Effect of Spraying on Thermal Fatigue Cracking
David Schwam, X.J. Zhu and J.F. WallaceCase Western Reserve University
NADCA DMC February 20, 2007
![Page 2: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/2.jpg)
Main Role of Die Spraying
• Facilitate casting release
• Prevent soldering
• Cool the die
Sprays of water-based lubricants are commonly used in high pressure die casting to provide both lubrication and cooling of the dies.
![Page 3: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/3.jpg)
Specimen and equipment
![Page 4: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/4.jpg)
Typical properties of H13
![Page 5: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/5.jpg)
Specimen for temperature measurement
![Page 6: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/6.jpg)
Parameters of the test• Total cycle time of 36 seconds (3 seconds
stroke down, 7 seconds immersion, 2 seconds stroke up, 14 seconds dwell, 3-13 seconds water spraying, one second air blowing and another 6 seconds dwell before stoke down).
• Air pressure is 45 psi and the estimated spraying rate is 1.25 ml/second.
![Page 7: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/7.jpg)
Effect of Spraying Time on Total Crack Area
![Page 8: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/8.jpg)
Effect of Spraying Time on Average Maximum Crack Length
![Page 9: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/9.jpg)
Discussion
= Where δ is the thermal stress, α is the linear thermal coefficient of expansions, E is the elastic modulus and ∆T is the temperature change. For biaxial condition the stress is given by:
= / 1- Where is Poisson’s ratio.
Larger lead to higher the thermal stresses.
![Page 10: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/10.jpg)
Typical Temperature Cycle with no Spraying(internal water cooling only)
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
40 50 60 70 80 90 100 110 120 130 140 150
Time(s)
Die
Temp
erat
ure
(F)
Surface0.08"
surface = 900 F
0.08 = 760 F
![Page 11: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/11.jpg)
Typical Temperature Cycle with 3 Seconds Spraying
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
130 140 150 160 170 180 190 200 210 220 230 240
Time(s)
Tem
pera
ture
(F)
Surface
0.08"
surface = 1182 F
0.08 = 800 F
![Page 12: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/12.jpg)
Typical Temperature Cycle with 8 Seconds Spraying
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
3350 3360 3370 3380 3390 3400 3410 3420 3430
Time(s)
Tem
pera
ture
(F
)
Surface
0.08"
surface = 1226 F
0.08 = 700 F
![Page 13: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/13.jpg)
Typical Temperature cycle with 13 seconds Spraying
surface = 1058 F
0.08 = 820 F
![Page 14: The Effect of Spraying on Thermal Fatigue Cracking David Schwam, X.J. Zhu and J.F. Wallace Case Western Reserve University NADCA DMC February 20, 2007.](https://reader036.fdocuments.net/reader036/viewer/2022062305/56649c9a5503460f9495811e/html5/thumbnails/14.jpg)
Conclusions
• As anticipated, the die lube spray has a significant effect on thermal fatigue cracking.
• Increasing the spray time increases both the total crack area and the average maximum crack length.
• This indicates that aggressive application of die lubricant spray will significantly reduce the die life.