a new fluidity die for castability evaluation of high ... · a new fluidity die for castability...
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A New Fluidity Die for Castability Evaluation of High
Pressure Die Cast AlloysA.D. Klarner, E. Cinkilic, Y. Lu, J. Brevick, A.A. Luo
The Ohio State UniversityJ. Shah
Product Development & Analysis (PDA) LLCM. Zolnowski
Boeing Research and TechnologyX. Yan
Alcoa Technical Center
LIFT - Melt 5B Project LIFT (Lightweight Innovations for Tomorrow) Project title: Thin-Wall Aluminum Die Casting
Development Project Topics: Alloys (Lift380 and EZCast) HPDC of test specimens and fluidity die
studies Microstructure characterization and modeling Cost modeling Industrial application: side impact beam
(CANMET)
Thin-Wall Aluminum Die Casting DevelopmentProject Team
Principal investigator: Mike Zolnowski, Boeing Industry partners:
Alcoa (Xinyan Yan)American Foundry Association (Zayna Conner, Tom Prucha)Boeing (Mike Zolnowski, Russ Cochran)Eaton (Matt Otte)North American Die Casting Association (Steve Udvardy, Beau Glim)Product Development & Analysis (Jiten Shah)
University/Research partners:Massachusetts Institute of Technology (R. Kirchain, M. Farooq)Ohio State University (A. Luo, J. Brevick, A. Klarner, E. Cinkilic)Southwest Research Institute (D. Riha)University of Michigan (J. Allison, T. Berman, Q. Shi)Worcester Polytechnic Institute (D. Apelian, L. Wang, J. Curto)
International partner: CANMET Materials (Kumar Sadayappan)
Develop super vacuum die casting with shortened heat treatment and ICME for 300 series (Al-Si-Cu-Mg based) die casting alloys
Improve strength and maintain ductility, reduce the minimum wall thickness (up to 40%) and weight (up to 20%).
Reduce quality variability and establish reliable minimum (not typical) properties of HPDC for design analysis.
Explore new design methods of lightweight castings using local mechanical properties predicted by ICME versus current casting design using minimum properties leading to overdesign and increased weight.
Deliverables will be design guidelines and property specifications for thin-wall aluminum die casting and ICME models for thin-wall casting design with location-specific properties.
Thin-Wall Aluminum Die Casting DevelopmentProject Objectives
Slide provided by Mike Zolnowski (SAE 2017)
From Micro to MacroFrom Research to Implementation;Thin-Wall Aluminum Die Casting Development
Slide provided by Mike Zolnowski (SAE 2017)
Experimental Alloys
Alloy Si Fe Cu Mg Mn Ni Zn Sr Ti AlEZCast 8.55 0.11 - 0.28 0.56 0.006 - 0.010 0.008 bal.Lift380 8.83 0.2 3.5 0.29 0.21 0.047 0.11 0.025 0.073 bal.A380.1 8.50 1.0 3.5 0.10 0.50 - 3.00 - 0.350 bal.
Alloy Liquidus (°C)
FCC Formation
(°C)
Solidus (°C)
Solidification Range (°C)
Fraction of Eutectic Liquid
EZCast 605 604 553 52 0.623Lift380 590 590 481 109 0.739A380 644 584 344 300 0.644
Higher fraction of eutectic liquid promotes better fluidity
Lift380 - lower solidus EZCast - small solidification range
Fluidity Die Studies Fluidity is a very important property in casting
especially for large thin-walled structural castings Thin-wall ⟶ fast cooling rate Very long flow distances
Currently most fluidity studies are in gravity casting condition Fluidity spiral test Vacuum fluidity test (Ragone)
Studies under HPDC conditions High pressures Fast cooling rates High velocities
2017 “International Magnesium Association Award of Excellence –Automotive Cast Product” (in collaboration with GM and Meridian)
Fluidity Die Goals Develop a die which is able to test the fluidity by
measuring experimental flow length ‘3D’ flow, to mimic real castings Thin wall sections of varying thicknesses, current
industry standard (3mm) to future (1mm) Effects of different processing parameters Effects of different alloys
Use simulation software to predict fluidity by flow lengths depending on alloy properties from CALPHAD Use experimental results to verify simulation results
Fluidity Die Design Three multi-dimensional thin-wall passages 1, 2, 3 mm wall thicknesses
(current thin wall castings to future)
Die designed by PDA (Jiten Shah) with input from Melt 5b team
Cooling Rates of Thin Walled Sections EZCast at melt temperature of
606 °C.
Average cooling rate is computed between temperatures 605 °C and 553 °C.
1 mm plate has the highest cooling rate with ~300 °C/s. 2 mm is ~200 °C/s while 3 mm is ~100 °C/s.
Rim of the plate has higher cooling rate than the middle
Unit: °C/s
𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 =𝑇𝑇𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢 − 𝑇𝑇𝑙𝑙𝑙𝑙𝑙𝑙𝑢𝑢𝑢𝑢𝑟𝑟𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢 − 𝑟𝑟𝑙𝑙𝑙𝑙𝑙𝑙𝑢𝑢𝑢𝑢
Tupper = liquidusTlower = solidus
EZCast
Simulations of Alloys at Same Temperature: High Temps
Same melt temperature (645 °C) for both cases At high temperatures, both alloys exhibit good fluidity EZCast has more uniform metal front with these parameters
74.5% filled, same simulated time
89.9% filled, same simulated time
Tliq 587.6
Tsol 505.6
Unit: °C
EZCast
Lift380
EZCast Lift380 EZCast Lift380
Simulations of Alloys at Same Temperature: Low Temps
Simulations preformed at 577°C Lift380 shows better fluidity when both alloy are at the same low
temperature - due to lower solidus temperature
Lift380Tsol 505.6
EZCast
Unit: °C
End of simulation
EZCast Lift380 EZCast Lift380
80.8% filled 85.7% filled
High Pressure Die Casting Cell at OSU Bulher 250 ton DCM Fondarex super vacuum
System (not used in these experiments)
2 furnaces allows for both magnesium and aluminum
Rimrock robotic ladling system
Rotary degassing unit (Pyrotek Star 2500)
HPDC Experimental Setup Gas furnace temperature ~100°C superheat Die temperature ~150°C, no oil lines 2 experimental aluminum alloys EZCast Lift380
Variable processing parameters Fast shot speed (0.5m/s to 5m/s; 4m/s to
40m/s gate velocity ) Melt volume (via changing ladle angle)
Flow Length Measurements
Two measurement methods ‘Good metal front’ - gate to
the point at which the metal front was disturbed
‘Full flow’ – gate to last point of flow
AlloyAverage Flow Length (full flow) Average
Superheat (°C)
Average Die Temperature
(°C)1mm 2mm 3mm
EZCast 38.2 71.7 199.5 93.9 141.5Lift380 52.1 110.8 187.3 95.4 132.3
0
65115
200
Flow Length Results
Full Flow
3mm Full Castings Total % FullEZCast 23 24 96%Lift380 16 21 76%
Flow Length Results
3mm would fill and backfill into thinner sections
1 and 2mm sections showed incomplete filling
EZCast Lift380
AlloyAverage Flow Length
(good metal front)1mm 2mm 3mm
EZCast 8.1 24.3 196.1
Lift380 11.9 79.4 184.9
Flow Length vs Shot Speed
Found linear response with shot speed 3mm filled all times above 1.5 m/s
2mm thin-wall had around double the flow length compared to 1mm Half average cooling rate
Full Flow
Good Metal Front
Speed (m/s) 1mm 2mm 3mm0.5 3.5 41.8 184.71.0 2.7 63.8 177.71.5 17.3 86.1 200.02.0 29.3 74.5 200.03.0 59.7 108.1 200.04.0 75.3 175.8 200.05.0 75.0 165.3 200.0
Wall Thinkness
0.5m/s
1m/s 1.5m/s
2m/s
3m/s 4m/s 5m/s
Alloy: Lift380
Flow Length vs Shot Speed
Simulations vs Partial Shots(Controlling Shot Volume)
As shot volume increases, flow length increases
Used reduced metal pours to create partial shots to look at metal front and compare to simulations
Alloy: Lift380
Simulations vs Actual Castings
Sample EZCast #92 had low furnace temperature (642°C)
Caused early solidification and fill pattern matches that of simulation at partial fill (80%)
EZCast at 80.8% filled
Simulations vs Actual Castings
Backfilling of 1mm section is shown in simulations Happened in experiments when temperature was low Quick solidification in 1mm
EZCast
EZCast fraction solid at final filling
Industry Application: Side Impact Beam
29’’
2.85’’
Length ~29 inches, Width ~2.85 inchesThickness 3mm through most of partPart Volume = 225cm^3 (~600g)
Industry Casting Trial at CANMETSide Impact Beam
Casting Trials conducted at CANMET, April 2017
Process parameters (velocity, melt temp, fill time) found using simulation
X-ray inspection by Boeing Simulations ran with trial
process parameters and correlated with experimental porosity measurements
Industry Casting Trial at CANMETSide Impact Beam
Simulation using actual casting trial processing parameters Predicted more porosity in Lift380 compared to EZCast
EZCast Lift380
Predicted primary shrinkage
Slide and simulation provided by PDA (Jiten Shah)
Side Impact Beam: Casting Quality
Typical E15-30
Worst E2
Sample E15 simulated, no indications
Lower plunger velocity, poor vacuum
EZCast
Slide and simulation provided by PDA (Jiten Shah)
Radiography performed by a Boeing certified level 3
technician
Side Impact Beam: Casting Quality
Typical samples: never were consistently defect free, matches simulation
No vacuum applied (1010mbar), higher melt temperature (757°C)
Lift380
Typical
Worst: L2
Slide and simulation provided by PDA (Jiten Shah)
Radiography performed by a Boeing certified level 3
technician
Conclusions The new “fluidity die” can be used to evaluate
castability and optimize processing parameters for different alloys by measuring flow length at different thicknesses.
Flow simulations using alloy specific properties (viscosity, etc.) can predict the flow length and pattern with reasonable accuracy.
Two experimental alloys, EZCast and LIFT, showed varied castability at different melt temperatures. Both alloys performed well in the “fluidity die” casting trials (at OSU), and industrial “side impact beam” casting trials (at CANMET).
Acknowledgements LIFT (Lightweight Innovations for Tomorrow) Entire LIFT Melt5b Project Team Bill Tullos, lead casting engineer at OSU OSU Center for Design and Manufacturing Excellence
(CDME) and Simulation Innovation and Modeling Center (SIMCenter)