DEFORM Simulation Results

2D Hot Forging and Air Cool of Gear Tooth Geometry

Holly Quinn12/04/2010

DEFORM Model

• 2D Axisymmetric Model

• Workpiece (Yellow) is Plastic and 2200°F

• Top and Bottom Dies are Rigid. All pieces are 300°F.

• Workpiece will be re-meshed when interference exceeds 0.00099.

• Initial Contact Pairs:

1. WP to Bottom Die2. WP to Top Die

Top Die

Bottom Die

Workpiece

Forging Simulation Setup and Results

Forging Simulation Settings

• Main– Axisymmetric Geometry– Modes

• Deformation• Heat Transfer

• Step Settings– Starting Step = -1– Number of Steps = 100– 1 Step = 0.01” Die Displacement– Max Strain in WP/step = 0.1– Primary Die = Top Die

• Iteration Settings– Solver = Skyline– Iteration Method = Newton-Raphson– Convergence Errors

• 0.001 for Velocity• 0.01 for Force

• Process Conditions– Heat Transfer

• Environment Temperature = 68F• Convection Coefficient=5.787e-6

But/sec/in2F

– Diffusion• Environment Atom Content = 1.69% atm• Reaction rate coefficient = 1e-5 in/sec

• Advanced– Contact Error Difference Tolerations =

0.0009

Materials

Top Die

Workpiece

Bottom Die

Temperature, Final Time step

Displacement

Flash

Flash

Effective Stress

Effective Strain

Effective Strain Rate

FlowNet Tracking of Material Flow

Microstructure Post Processing of Forging

• Two Areas examined:– Points within gear “core”

• Points 6, 18, 21

– Points near exterior of gear tooth• Points 14, 15, 16

• Grain Orientation Plot• Average Grain Size from beginning to end

of forging (Step 1 – 43)

Microstructure Post Processing Settings• Discrete Lattice: Cellular Automata, (50x50) Square• Horizontal and Vertical BCs: Periodic, Wrap Around• Grain boundary and Neighborhood:

– Grain Boundaries coupled to material flow: No– Neighbor Hood: Moore’s Neighborhood, R=1

• Dislocation Density Calculation Constants– ε0=1 Q=416,780 h0=0.00075– r0=2000 K=6000 m=0.0055

• Recrystallization Phenomena: DRX• Nucleation Conditions for new grains: Function of a threshold dislocation

density• Nucleation Conditions for new grains: n/a• Grain growth phenomena selection and material constants:

– Grain Growth: Function of GB migration velocity, constant=1• Flow Stress phenomena selection and material constants:

– n/a– ρi = 1– D=0.1– δ=0.1

• Initial MS Input:– Generate GB and orientations separately: System generate, average GS = 0– Generate GB Orientations: System generate, random– Initial dislocation density ρi=0.01

Microstructure – Core Locations Grain Orientation, Step 1

P6

P18

P21

Microstructure – Core Locations Grain Orientation, Step 43

P6

P18

P21

Microstructure – Core Locations Grain Size Histogram, Step 1

P18

P21

P6

Point 6:Average GS=9.70

Point 18:Average GS=9.50

Point 21:Average GS=9.76

Microstructure – Core Locations Grain Size Histogram, Step 43

Point 6:Average GS=2.05

Point 18:Average GS=1.89

Point 21:Average GS=2.02

P6

P18

P21

Microstructure – Core Locations Grain Boundary Misorientation, Step 1

P18

P21

P6

Microstructure – Core Locations Grain Boundary Misorientation, Step 43

P6

P18

P21

Microstructure – Tooth Locations Grain Orientation, Step 1

P16

P15

P14

Microstructure – Tooth Locations Grain Orientation, Step 43

P16

P14

P15

Microstructure – Tooth Locations Grain Size Histogram, Step 1

Point 14:Average GS=9.80

Point 15:Average GS=9.59

Point 16:Average GS=9.81

P16

P15

P14

Microstructure – Tooth Locations Grain Size Histogram, Step 43

Point 14:Average GS=1.97

Point 15:Average GS=2.07

Point 16:Average GS=1.91

P16

P15

P14

Decreased Grain Size in Core and Tooth Areas (from Step 1 to 43)

• Gear Core Grain Size Changes– Point 6: 9.70 2.05– Point 18: 9.50 1.89– Point 21: 9.76 2.02

• Gear Tooth Grain Size Changes– Point 14: 9.80 1.97– Point 15: 9.59 2.07– Point 16: 9.81 1.91

Cooling Simulation Setup and Results

Air Cool Simulation Settings Pyrowear 53

• Main– Axisymmetric Geometry– Modes

• Deformation• Phase Transformation

• Mesh– #Structured Surface Mesh

Layers=2– Layer Thicknesses: 1=.005,

2=.01• Workpiece Initialization

– Don’t Initialize Temperature– Phase Volume Fraction

(Austenite)=1– Temperature = 2200°F

• Step Settings– Starting Step = -44

(last step of forging)– (Max) Number of Steps = 1000– 1 Step = 5°F– Min Temp Time Step = 5 sec– Max Temp Time Step = 30 sec– Duration = 5400 sec

• Process Conditions– Heat Transfer

• Environment Temperature = 68F• Coefficient=5.787e-06But/sec/in2F

• Boundary Conditions– Outside of Gear, all surfaces– Media Type = Air– Environment Temperature = 68°F– Convection Coefficient = 5.787e-06

But/sec/in2F– Symmetrical planes in vertical and

horizontal directions• Material

– Pyrowear, Heat Treat

*Heat Treat Wizard used for Model Setup

Pyrowear 53 Temperature (°F)

Time Step #5Time = 25 seconds

Step #250Time = ½ hour

Step #425Time = 1 ½ hrs

Pyrowear 53 Temperature (°F)

Step #155Time = 13 minutes

~1260°F

Pyrowear 53 Phase Transformation, Time=0

Pyrowear 53 Phase Transformation

Time=1000 seconds

Austenite Martensite Tempered Ferrite + Cementite

Temperature

Pyrowear 53 Phase Transformation

Time=1800 seconds

Austenite Martensite Tempered Ferrite + Cementite

Temperature

Pyrowear 53 Phase TransformationTime=5400 seconds

Ferrite Martensite Tempered Ferrite + Cementite

Tempered Martensite

Temperature

Pyrowear HardnessStep 425, Time = 5400 seconds

Pyrowear 53 TTT Diagram

Pyrowear 53 Air Cool: Time Vs Temperature

Gear Cooling Rate (Pyrowear 53)

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

0 100 200 300 400 500 600 700 800 900

Time (seconds)

Tem

per

atu

re (

F)

Gear Core

Gear Case