COLT Design Manual for Cold Forging Dies Case study: tripods and cross-joints (1) Case study: Cold forging of tripods and cross-joints • Die.
Download ReportTranscript COLT Design Manual for Cold Forging Dies Case study: tripods and cross-joints (1) Case study: Cold forging of tripods and cross-joints • Die.
Slide 1
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (1)
Case study: Cold forging of tripods and cross-joints
• Die material:
ASP 23, 60 HRc
Cold forged tripods and cross-joints
• Prestressing system:
ID 85 mm, OD 280 mm
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 2
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (2)
Typical failure mode
Fatigue cracks in a tripod die
Fatigue cracks in a cross-joint die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 3
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (3)
FE analysis of the tooling system
A) conventional container with a double ring
0.6% interference
B) STRECON® Basic, 0.8% interference
windings
and casing
C) STRECON® E+, 0.6% interference
winding core
die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 4
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (4)
A) Prestressing by a double stress ring at 0.6% interference
Circumferential stress distribution
at max. process load
500
MPa
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
330
MPa
Tangential stress in MPa
400
Tangential stress-strain response
in the critical area (5 load cycles)
0
-500
-1000
-1500
-2000
-2500
-1.5
-1
-0.5
0
0.5
1
Tangential total strain in %
risk of early crack initiation due to tensile stresses and large plastic strains
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 5
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (5)
B) Prestressing by STRECON® Basic at 0.8% interference
Circumferential stress distribution
at max. process load
500
MPa
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
60
MPa
Tangential stress in MPa
400
Tangential stress-strain response
in the critical area (5 load cycles)
0
-500
-1000
-1500
-2000
-2500
-1.5
-1
-0.5
0
0.5
1
Tangential total strain in %
Reduced max. tensile stress, but still considerable plastic strains
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 6
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (6)
C) Prestressing by a STRECON® E+ at 0.6% interference
Circumferential stress distribution
at max. process load
500
MPa
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
-320
MPa
Tangential stress in MPa
400
Tangential stress-strain response
in the critical area (5 load cycles)
0
-500
-1000
-1500
-2000
-2500
-1.5
-1
-0.5
0
0.5
1
Tangential total strain in %
Improved fatigue life: no tensile stresses, reduced stress range and cyclic plastic strains
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 7
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (7)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended die material:
• Power-metallurgical tool steel (instead of carbide),
provides an excellent fatigue strength
Recommended prestressing system:
• STRECON® E+
reduces the stresses and cyclic plastic strains,
leads to improved fatigue life
- the outer diameter of the die insert should be close to the inner
contour (better effectivity of the carbide winding core)
• STRECON® Basic
in case of long-legged parts (especially cross-joints),
where a carbide winding core would not be that effective
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (1)
Case study: Cold forging of tripods and cross-joints
• Die material:
ASP 23, 60 HRc
Cold forged tripods and cross-joints
• Prestressing system:
ID 85 mm, OD 280 mm
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 2
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (2)
Typical failure mode
Fatigue cracks in a tripod die
Fatigue cracks in a cross-joint die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 3
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (3)
FE analysis of the tooling system
A) conventional container with a double ring
0.6% interference
B) STRECON® Basic, 0.8% interference
windings
and casing
C) STRECON® E+, 0.6% interference
winding core
die
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 4
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (4)
A) Prestressing by a double stress ring at 0.6% interference
Circumferential stress distribution
at max. process load
500
MPa
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
330
MPa
Tangential stress in MPa
400
Tangential stress-strain response
in the critical area (5 load cycles)
0
-500
-1000
-1500
-2000
-2500
-1.5
-1
-0.5
0
0.5
1
Tangential total strain in %
risk of early crack initiation due to tensile stresses and large plastic strains
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 5
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (5)
B) Prestressing by STRECON® Basic at 0.8% interference
Circumferential stress distribution
at max. process load
500
MPa
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
60
MPa
Tangential stress in MPa
400
Tangential stress-strain response
in the critical area (5 load cycles)
0
-500
-1000
-1500
-2000
-2500
-1.5
-1
-0.5
0
0.5
1
Tangential total strain in %
Reduced max. tensile stress, but still considerable plastic strains
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 6
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (6)
C) Prestressing by a STRECON® E+ at 0.6% interference
Circumferential stress distribution
at max. process load
500
MPa
200
0
-200
-400
-600
-800
-1000
-1200
-1400
-1600
-320
MPa
Tangential stress in MPa
400
Tangential stress-strain response
in the critical area (5 load cycles)
0
-500
-1000
-1500
-2000
-2500
-1.5
-1
-0.5
0
0.5
1
Tangential total strain in %
Improved fatigue life: no tensile stresses, reduced stress range and cyclic plastic strains
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.
Slide 7
COLT Design Manual for Cold Forging Dies
Case study: tripods and cross-joints (7)
Recommendations for the design
of dies for the cold forging of tripods and cross-joints
Recommended die material:
• Power-metallurgical tool steel (instead of carbide),
provides an excellent fatigue strength
Recommended prestressing system:
• STRECON® E+
reduces the stresses and cyclic plastic strains,
leads to improved fatigue life
- the outer diameter of the die insert should be close to the inner
contour (better effectivity of the carbide winding core)
• STRECON® Basic
in case of long-legged parts (especially cross-joints),
where a carbide winding core would not be that effective
Established within the GROWTH project GRD1-1999-10748 "Improvement of Service Life and Reliability of Cold Forging Tools
with respect to Fatigue Damage due to Cyclic Plasticity (COLT)", funded by the European Community.