2.2.7.a. Ekstrudeerimine
• 1. Protsesside klassifitseerimine.
• 2. Töövahendid e. seaded.
• 3. Tooriku deformeerumine, määrded ja
defektid ekstrudeerimisel.
• 4. Ekstrudeerimisprotsessi analüüs, pingeja deformatsiooniolek.
• 5. Probleemid ja defektid ekstrudeerimisel.
Ekstrudeerimine
• Ekstrudeerimisprotsesside
klassifitseerimine
• Kuumalt
• Külmalt
• Päriekstrudeerimine
• Vastuekstrudeerimine
Meetodid
High production rate
Excellent dimensional tolerance and surface finish of extruded part
Significant savings in material and machining
Higher tensile strength in the extruded part than in original material
Favorable grain flow to improve strength
High production rate
Excellent dimensional tolerance and surface finish of extruded part
Significant savings in material and machining
Higher tensile strength in the extruded part than in original material
Favorable grain flow to improve strength
Ekstrudeerimise stantsi plokk
Skeem
D
CL
• Die Insert Inner Diameter,
• Billet Length,
D
Punch
L
• Extrude Diameter, d
Billet
L
α
R
• Die (Opening) Angle, α
• Die Land, l
• Die Radius,
l
r
R
• Transition Radius,
r
Container
d
Jõu arvestus
2
2 ln Rµ 

P = Aoσ ave  ln R + α +
+ πDLσ o µ

3
sin 2α 

(lbf)
In Ref. [7]
σ o (psi)
σ ave =
Ao D 2
R=
=
A1 d 2
K (ln R )
(psi)
n+1
Ao , A1 (in.2)
µ
α , D, L
(degree, inch, inch)
Material Factors: σ o ,σ ave
Geometrical Factors: α , D , L , R
Load(klb)
160
140
120
100
80
60
40
20
0
5
10
15
30
55
Die Angle(degree)
70
Load-Stroke Curve
Load(klb)
60
50
40
30
20
10
0
0.0
0.4
0.8
1.2
1.6
Punch Stroke(in.)
2.0
Deformatsioonitemperatuur
Päri- ja vastuekstrudeerimine
Deformatsioonikiirused
ekstrudeerimisel
Erinevad deformatsioonikolde
kujud ekstrudeerimisel
Backward Cup Extrusion
Definition of Geometric
Variables
- Backward Cup Extrusion
Criteria
- Effect of Punch Face
Shape
- Punch Nose Design
- Load Calculation
- Parametric Evaluation by
FEM
Material (Flow Stress)
Reduction in Area
Included Face Angle
Billet Length
Vastuekstrudeerimine
CL
Punch
R
β
L
Billet
df
l
2α
dP
Ejector
D
Container
Templi vormid ekstrudeerimisel
Deformatsiooniliinid
Load-punch stroke curve
Load(klb)
250
200
150
100
50
0
0.00 0.14 0.29 0.42 0.49 0.56 0.64
Punch Stroke(in.)
Parametric Evaluation by FEM (4.6)
Billet Length III
(4.6.5)
Strain vs. radius
Case A
Case B
L1=0.8 in.
L2=0.4 in.
ε max = 4.201
ε max = 2.576
Max. strain
at punch land
a
b
Unit:in.
- Punch face shape determines a metal flow pattern
since points a and b show the same strain values
COLD AND HOT FORGING
Fundamentals and Applications
ERC
NSM
H
APPENDIX 17.3
Backward Cup Extrusion
ERC for Net Shape Manufacturing
The Ohio State University
Columbus, Ohio
Phone: 614-292-9267 Fax: 614-292-7219
http://www.ercnsm.org
Appendix to Cold and Hot Forging: Fundamentals and Applications. © ASM International®. All Rights Reserved.
Introduction (0)
Backward Cup Extrusion
(4)
(2.1.2.2.1)
- Definition of Geometric Variables
- Backward Cup Extrusion Criteria
- Effect of Punch Face Shape
- Punch Nose Design
- Load Calculation
- Parametric Evaluation by FEM
• Material (Flow Stress)
• Reduction in Area
• Included Face Angle
Tool setup for
backward cup extrusion
• Billet Length
- The metal flow is opposite to the direction of punch movement
Introduction (0)
Backward Cup Extrusion
(4)
(2.1.2.2.1)
- Backward Cup Extrusion Animation
Please click on the image to view this simulation
The metal flow is opposite to the direction of punch movement
Backward Cup Extrusion (4)
Definition of Geometric Variables
(4.1)
CL
• Die Inner Diameter,
• Billet Length,
D
L
Punch
• Punch Diameter, d P
R
• Flat Diameter, d
f
• Included Face Angle, 2α
• Punch Land, l
• Punch Radius,
• Relief Angle, β
β
L
Billet
df
l
2α
R
dP
Ejector
D
Container
Backward Cup Extrusion (4)
Backward Cup Extrusion Criteria
(4.2)
CL
• Max & Min Reduction in Area:
20 ~ 25% ≤ % R .A . ≤ 70 ~ 75%
d2
%R .A . = 2 × 100
D
Punch
P
w
• Max Depth of Extruded Hole:
h = 2 ~ 3× dP
• Min Bottom Thickness
h
Billet
t
of Extruded Cup:
t = 1 ~ 1.5 × w
Ejector
Container
Backward Cup Extrusion (4)
Punch Face Geometry (4.3)
- The punch face shape has a significant effect on the frictional force and metal flow
Highest
pressure
Lower
pressure
Combination
Flat
Conical
Flat & conical
Lowest pressure
but limited application
Spherical
- Advantage of the combination is that the lubricant carrier and the
lubricant cannot be separated easily or overextended locally as is
the case with conical faces
Backward Cup Extrusion (4)
Punch Nose Design (4.4)
Based on Punch Diameter,
CL
dP
• Flat Diameter,
d f = d P − [ 2 R + ( 0.2 ~ 0.3 )d P ]
• Included Face Angle,
2α = 160 o ~ 170 o
• Punch Land,
l = 0 . 3 ~ 0 .7 × d P
β
R
d
f
l
• Punch Radius,
R = 0.05 ~ 0.1 × d P
• Relief Angle,
β = 4o ~ 5o
2α
d
p
Punch design recommended by ICFG [6]
Backward Cup Extrusion (4)
Load Calculation (4.5)
- Formulas for predicting the forging load in backward extrusion are derived
either through approximate method of plasticity theory or empirically
from a series of experiments
P = Aoσ o (3.45 ln R + 1.15 )
• Yield stress,
• Extrusion ratio,
σo
(lbf) for 0.1 to 0.3% C steel
In Ref. [7]
(psi)
Ao D 2
R=
=
A1 d 2p
Initial, final cross sec. Area,
Ao , A1 (in2)
- None of the formulas for the prediction of extrusion load take into
account the punch geometry (i.e.,included face angle, punch radius)
Material Factors:
Geometrical Factors:
σo
R
Backward Cup Extrusion (4)
Parametric Evaluation by FEM
(4.6)
- Factors affecting load in backward cup extrusion
• Flow stress,
σ = f (ε , ε& ,T , S )
ε
ε&
T
S
Effective strain
Effective strain-rate
Temperature
Microstructure
Material
• Reduction in area,
% R .A . = f ( D , d )
• Included face angle, 2α
• Billet length, L
• Diameter, D
Tool Geometry
Billet Dimensions
Parametric Evaluation by FEM (4.6)
Parameters Considered in FEM (4.6.1)
44 Parameters
Parameters in
in
FEM
FEM simulations
simulations
CL
Velocity Profile of Mechanical
Press is Considered
Punch
R
β
4. Billet Length
(0.8 in., 0.4 in.)
L
Billet
df
2α
3. Reduction in Area
(30%, 60%)
1. Material (Flow Stress)
(AISI 1020, 1035)
2. Included Face Angle
(160o, 170o)
dP
Ejector
D
Container
Billet Diameter is fixed to 1.0 in.
Parametric Evaluation by FEM (4.6)
Material
(4.6.2)
• Simulation Conditions
%R.A. : 60%,
Included Face Angle : 160o
Size (L x D) : 0.8 x 1.0 in.
Load-Stroke Curve
Load(klb)
Case B
250
200
150
- The load increases rapidly to
its max and then reduces
slowly to its final value
100
Case A
50
0
- The flow stress of the billet
0.0
0.1
material directly influences
the extrusion load
0.2
0.3 0.4 0.5 0.6
Punch Stroke(in.)
0.7
• Flow stress
Case A : AISI 1020, σ = 108.1ε 0.20 ( ksi )
Case B : AISI 1035, σ = 130.8ε
0.17
( ksi )
Parametric Evaluation by FEM (4.6)
Reduction in Area I
(4.6.3)
• Simulation Conditions
Material AISI 1035
Included Face Angle : 160o
Size (L x D) : 1.0 x 1.0 in.
Load-Stroke Curve
Load(klb)
- The extrusion load increases
with increasing reduction in
200
150
Case B
100
50
Case A
area because the amount of
deformation increases
0
0.0
- The higher the reduction in area
the more the load decreases
after peak point
0.2
0.4
0.6
0.8
Punch Stroke(in.)
• Reduction in Area (%R.A.)
Case A - 30%, Case B - 60%
Parametric Evaluation by FEM (4.6)
Reduction in Area II
(4.6.3)
Strain vs. Radius
Case A
Case B
%R.A. = 30%
%R.A. = 60%
0.14 ≤ ε max ≤ 4.73
0.29 ≤ ε max ≤ 4.12
Max. strain
Unit:in.
- The greater the reduction in area, the higher the effective strain
Parametric Evaluation by FEM (4.6)
Included Face Angle I
(4.6.4)
• Simulation Conditions
Material AISI 1035
%R.A. : 60%
Size (L x D) : 1.0 x 1.0 in.
Load-Stroke Curve
Load(klb)
Case A
250
200
- Generally, the value of punch
pressure decreases with
decreasing included face
angle, 2α
- Case B shows slightly lower
load than Case A
150
Case B
100
50
0
0.0
0.2
0.4
0.5
0.7
Punch Stroke(in.)
0.8
• Included Face Angle, 2α
Case A - 170o, Case B - 160o
Parametric Evaluation by FEM (4.6)
Included Face Angle II
(4.6.4)
Strain vs. Radius
Case A
Angle, 2α = 160o
0.36 ≤ ε ≤ 3.96
Case B
Angle,2α = 170o
0.31 ≤ ε ≤ 3.96
Unit:in.
Parametric Evaluation by FEM (4.6)
Included Face Angle III
(4.6.4)
Zoomed on punch face
(Local metal flow)
Case A
Case B
Angle, 2α = 160o
Angle, 2α = 170o
- Included face angle of 160o gives better material flow
around punch nose region
Parametric Evaluation by FEM (4.6)
Billet Length I
(4.6.5)
Case A
Case B
- In backward extrusion, the billet
length has little effect on the
extrusion load
Punch
- However, when billet length was
longer, high value of strain was
Billet
L1
Punch
Billet
predicted near the punch land
Container
L1 = 0.8( in .)
L2
Container
L2 = 0.4 ( in .)
Parametric Evaluation by FEM (4.6)
Billet Length II
(4.6.5)
• Simulation Conditions
Material : AISI 1035
%R.A. : 60%
Included Face Angle : 160o
Load-punch stroke curve
Load(klb)
250
200
150
- Decrease in load is caused by
the decrease in the volume
of material participating in
the deformation process
100
Case A
Case B
50
0
0.00 0.14 0.29 0.42 0.49 0.56 0.64
Punch Stroke(in.)
• Billet Length
Case A :
Case B :
L1 = 0.8( in .)
L2 = 0.4 ( in .)
Parametric Evaluation by FEM (4.6)
Billet Length III
(4.6.5)
Strain vs. radius
Case A
Case B
L1=0.8 in.
L2=0.4 in.
ε max = 4.201
ε max = 2.576
Max. strain
at punch land
a
b
Unit:in.
- Punch face shape determines a metal flow pattern
since points a and b show the same strain values
Introduction (0)
Lateral Extrusion with Multi-Action Tooling (5)
(2.1.2.2.1)
Punch
Die
- Definition of Geometric Variables
- Load Calculation
- Parametric Evaluation by FEM
Billet
• Material (Flow Stress)
• Extrude Height
Die
• Billet Length
Ejector
Tool setup for axisymmetric
lateral extrusion
- In this module only axisymmetric (round) parts
are considered. In practice lateral extrusion is
also applied to form non-axisymmetric parts
Introduction (0)
Lateral Extrusion with Multi-Action Tooling (5)
(2.1.2.2.1)
- Lateral Extrusion Animation
Please click on the image to view this simulation
The metal flow is perpendicular or at an angle
to the direction of punch movement
Lateral Extrusion with Multi-Action Tooling (5)
Definition of Geometric Variables
(5.1)
CL
• Die Inner Diameter,
D
Punch
• Billet Length,
L
L
Billet
Container
h
• Extrude Height, h
Container
• Extrude Diameter,
E
D
E
Lateral Extrusion with Multi-Action Tooling (5)
Load Calculation
(5.2)
- Formulas for predicting the lateral extrusion loads
2
 
D 4 h   2 E  
P = 0.866 Aoσ ave  1.366 +
+
+  ln

 
2
h
3
D
D
 
 
 
(lbf)
In Ref. [7]
• Average flow stress of strain hardening material,
σ ave =
K ( ε ave )
(psi)
n+1
• Average effective strain,
ε ave
D 2d   2 E 
= 0.683 +
+
+  ln

8 h 3 D   D  
2
• Die inner diameter, Extrude diameter,
D,E
(inch, inch)
Material Factors:
Geometrical Factors:
σ ave
D , h, E
Lateral Extrusion with Multi-Action Tooling (5)
Parametric Evaluation by FEM
(5.3)
- Factors affecting load in lateral extrusion
• Flow stress,
σ = f (ε , ε& ,T , S )
ε
ε&
T
S
Effective strain
Effective strain-rate
Temperature
Microstructure
• Extrude height,
• Billet length, L
h
Material
Tool Geometry
Billet Dimension
Parametric Evaluation by FEM (5.3)
Parameters Considered in FEM
33 Parameters
Parameters in
in
FEM
FEM simulations
simulations
D
CL
(5.3.1)
Billet Diameter is fixed to 1.0 in.
Velocity Profile of Mechanical
Press is considered
Punch #1
1. Material (Flow Stress)
(AISI 1020, 1035)
3. Billet Length
(1.5 in., 1.0 in.)
Container
L
h
Billet
Container
Punch #2
2. Extrude Height
(0.25 in., 0.15 in.)
Parametric Evaluation by FEM (5.3)
Material I
(5.3.2)
• Simulation Conditions
Size (L x D) : 1.5 x 1.0 in.
Stroke : +/- 0.15 in. / punch
Extrude height : 0.25 in.
Load-Stroke Curve
Load(klb)
250
Case A
200
150
- Loads increase monotonously
as the upper and the bottom
punch move toward each other
100
Case B
50
0
0.00
0.03
- As punch stroke increases,
the difference between
A and B becomes greater
0.06
0.09 0.12
Punch Stroke(in.)
0.15
• Flow stresses
Case A : AISI 1035, σ = 130.8ε 0.17 ( ksi )
Case B : AISI 1020, σ = 108.1ε
0.20
( ksi )
Parametric Evaluation by FEM (5.3)
Material II
(5.3.2)
Strain vs. Radius
Case A
Case B
AISI 1035
AISI 1022
Max. strain
ε max = 1.39
ε max = 1.81
Unit:in.
- At center, rapid metal flow in radial direction leads to
higher strain when billet material of AISI 1022 is used
Parametric Evaluation by FEM (5.3)
Extrude Height I
(5.3.3)
• Simulation Conditions
Material AISI 1035
Size (L x D) : 1.5 x 1.0 in.
Stroke : +/- 0.15 in. / punch
Load-Stroke Curve
Load(klb)
350
Case A
300
250
200
150
- When the extrude height was
reduced by 40%, load increases
by about 30%
100
Case B
50
0
0.00
0.03
0.06 0.09 0.12
Punch Stroke(in.)
• Extrude Height
Case A :
Case B :
h1 = 0.25 ( in .)
h2 = 0.15 ( in .)
0.15
Parametric Evaluation by FEM (5.3)
Extrude Height II
(5.3.3)
Strain vs. Radius
Case A
Case B
d1=0.25 in.
d2=0.15 in.
ε max = 1.39
ε max = 1.79
Max.
strain
Unit:in.
- Once metal flow in the lateral direction is started
max. strain is developed
Parametric Evaluation by FEM (5.3)
Billet Length I
(5.3.4)
• Simulation Conditions
Material : AISI 1035
Stroke : +/- 0.15 in. / punch
Extrude height : 0.25 in.
- For different billet lengths
investigated here,
no changes in load
were predicted
Load-Stroke Curve
Load(klb)
250
Case A
200
150
Case B
100
50
0
0.00
0.03
- However, if L is very large
some increase in load
due to friction can be expected
0.06 0.09 0.12
Punch Stroke(in.)
• Billet Length
Case A :
Case B :
L1 = 1.5 ( in .)
L2 = 1.0 ( in .)
0.15
Parametric Evaluation by FEM (5.3)
Billet Length II
(5.3.4)
Strain vs. Radius
Rigid
zone
Case A
Case B
L1=1.5 in.
L2=1.0 in.
ε max = 1.39
ε max = 1.41
Unit:in.
- For these two different billet lengths,
there is no significant difference in strain values
Cold Extrusion
Glossary
(G)
- Forward Rod Extrusion: The metal flow is in the direction of the ram motion
• Open Die Extrusion: Reduction of the cross section without supporting
the undeformed portion of the component in a container
• Trapped Die Extrusion: In forward extrusion, the entire billet is supported
by the container
- Backward Extrusion: The metal flow is opposite to the direction of the ram motion
of the machine
• Backward Cup Extrusion: A thin-walled hollow body is extruded from
a solid component by backward extrusion
- Lateral Extrusion: The flow of metal is perpendicular or at an angle to direction of
the ram motion
Cold Extrusion
Nomenclature
(N)
Backward Extrusion
• Reduction in Area, % R .A .
• Die Inner Diameter, D
• Punch Diameter, d P
• Flat Diameter, d f
• Included Face Angle, 2α
• Punch Land, l
• Punch Radius, R
• Relief Angle, β
• Hole Depth, h
• Bottom Thickness, t
Lateral Extrusion
• Die Inner Diameter, D
• Extrude Height, h
• Extrude Length, L
• Extrude Diameter, E
Load Calculation
• Flow stress, σ
• Yield Stress, σ o
• Average Flow Stress, σ ave
• Average Effective Strain, ε ave
Cold Extrusion
References
(R)
[1] Metal Forming: Fundamentals and Applications, T. Altan, S.I. Oh,
and Harold L. Gegel, American Society for Metals, 1983
[2] Product and Forming Sequence Design for Cold Forging,
H. Kim, K. Sevenler, and T. Altan, ERC/NSM-B-D-91-52, 1991
[3] A User’s Manual for FORMEX 1.0,
H. Kim, K. Sevenler, and T. Altan, ERC/NSM-B-D-91-55, 1991
[4] Defects in Cold Forging, Final Report, ICFG Subgroup “Material
and Defects,” 1996
[5] Source Book on Cold Forging, American Society for Metals, 1975
[6] Cold Forming, ICFG, 1992
[7] P.S. Raghupathi, S.I. Oh and T. Altan,”Methods of Load Estimation in
Flashless Forging Process,” Topical Report No. 10, Battelle Columbus
Lab., August 1982
[8] Deform 2D User Manual, SFTC, Columbus OH, 1996