A Study of Die Failure Mechanisms in Aluminum Extrusion Presented By: Brian B. Cherry Date: September 15, 2004 Class: Me 582, Professor Ed Red Authors:

A Study of Die Failure A Study of Die Failure Mechanisms in Aluminum Mechanisms in Aluminum

ExtrusionExtrusion

Presented By:Presented By: Brian B. Cherry Brian B. Cherry

Date:Date: September 15, 2004 September 15, 2004

Class:Class: Me 582, Professor Ed Red Me 582, Professor Ed Red

Authors:Authors: A.F.M Arif, A.K. Sheikh, S.Z. Quamar

Received:Received: November 27, 2001

Published By:Published By: Journal of Materials Processing Technology,

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IntroductionIntroduction Profile terminology / Die ProfilesProfile terminology / Die Profiles Overall and class-wise break-up of failure Overall and class-wise break-up of failure

modesmodes Type failure analysis per shapeType failure analysis per shape Shape-wise breakdown of each failureShape-wise breakdown of each failure

modemode Conclusion / ReferencesConclusion / References

What is Extrusion?What is Extrusion? A compression forming process in which the work metal is forced A compression forming process in which the work metal is forced

through a die opening to produce a desired cross-sectional shape.through a die opening to produce a desired cross-sectional shape.

Relatively simple shapes…

..Or more complex shapes

The bulk of aluminum profiles in the construction industry is produced through hot extrusion. Above is

An extrusion press container.

Purpose of Technical PaperPurpose of Technical Paper Productivity, cost and quality Productivity, cost and quality

are the overriding commercial are the overriding commercial factors. All three are related to factors. All three are related to the performance of the die.the performance of the die.

Due to the high cost of a die Due to the high cost of a die based on material processing based on material processing and fine tolerances, the most and fine tolerances, the most critical extrusion component is critical extrusion component is the die.the die.

It is of considerable interest to It is of considerable interest to focus on the relationship focus on the relationship between die profiles and between die profiles and modes of die failure.modes of die failure.

Testing: 616 dies, 17 various Testing: 616 dies, 17 various profiles, H-13 steel.profiles, H-13 steel.

All billets are made of Al-6063.All billets are made of Al-6063.

Bling..Bling!!

Getting Rejected is Expensive And Embarrassing!!

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IntroductionIntroduction Profile terminology / Die ProfilesProfile terminology / Die Profiles Overall and class-wise break-up of failure Overall and class-wise break-up of failure

modesmodes Various complexity failure analysisVarious complexity failure analysis Shape-wise breakdown of each failureShape-wise breakdown of each failure

modemode Conclusion / ReferencesConclusion / References

Die and Tooling ConfigurationDie and Tooling Configuration

Die and Tooling Configuration for hot extrusion of A1-6063.Die:Die: Produces the extrusion shape.Die Ring:Die Ring: Holds the die, the feeder plate and the die backer together.Die Bolster:Die Bolster: Provides support to the die against collapse or fracture. Transfers the extrusion load from the die to the pressure ring.

Liner:Liner: Provides protection against thermal and mechanical stresses to the large and expensive container.

Stem:Stem: It is fitted with the main ram to force the billet through the container.Dummy Pad:Dummy Pad: Floating or fitted in front of the stem. It protects the life of the costly stem.

Pressure Pad:Pressure Pad: Transfers the extrusion load from the bolster to the pressure plate and also guards against bolster deflection.

Configuration of a Typical DieConfiguration of a Typical Die

Configuration of a solid flat-face die.

Die ProfilesDie Profiles

Common features of die profiles

Three types of die profiles

Hollow Dies

Semi-Hollow Dies

Solid Dies

Die ProfilesDie Profiles

Sketches and die profiles used in the study.

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IntroductionIntroduction Profile terminology / Die ProfilesProfile terminology / Die Profiles Overall and class-wise break-up of failure Overall and class-wise break-up of failure

modesmodes Various complexity failure analysisVarious complexity failure analysis Shape-wise breakdown of each failureShape-wise breakdown of each failure

modemode Conclusion / ReferencesConclusion / References

More TerminologyMore Terminology Crack: A visible, generally uneven fissure on the surface.Crack: A visible, generally uneven fissure on the surface. Break: Component is broken in two.Break: Component is broken in two. Chip off: A small piece is chipped off the surface.Chip off: A small piece is chipped off the surface. Wash Out: Tiny but sig. craters or depressions cause by pitting or Wash Out: Tiny but sig. craters or depressions cause by pitting or

erosion.erosion.

Fracture:Fracture: All fatigue failures. Cracking, chipping, All fatigue failures. Cracking, chipping, breaking, surface fatigue, ect.breaking, surface fatigue, ect.

Wear:Wear: Gradual surface deterioration. Gradual surface deterioration. Deflection:Deflection: Going out of shape, or sub-component Going out of shape, or sub-component

owing to excessive plastic deformation.owing to excessive plastic deformation. Mixed:Mixed: A combination of the above failures. A combination of the above failures. Mandrel:Mandrel: When the die has to be scrapped due to any When the die has to be scrapped due to any

failure in the mandrel.failure in the mandrel. Miscellaneous:Miscellaneous: Not specifically any of the above Not specifically any of the above

failures. Softening of the die or bearingfailures. Softening of the die or bearing

Failure Types for all Dies

Fracture46.0%

Wear26.0%

Deflection19.0%

Mixed4.0%

Miscellaneous2.0%

Mandrel3.0%

Wear Failures

DimC/OS/OW97.0%

BWO3.0%

Deflection FailuresTBt/TDf

3.0%

Df96.0%

CvDf1.0%

Miscellaneous Die Failure

BD59%DS/BS

17%

CvDm8%

Dm8%

NOF8.0%

Fracture Type Failures

BPB/PB68.5%

BB/BC1.7%

BCO5.9%

DB/DC10.4%

CC7.6%

SfC0.3%

TB/TC2.1%

TpB1.4%

ScB/SHB1.0%

DtB0.3%

CvB0.7%

Class-Wise Breakup of Failure ModesClass-Wise Breakup of Failure ModesBPB=brush path brokenCC=corner crackDB=die brokenBCO=bearing chipping

DimC=dimension changeBWO=bearing wash-out

Df=die deflectedTBt=tongue bent/deflected

BD=bearing damageDS=die softening

Observations:1. This supports intuitive reasoning. With large

number sharp corners, projections and protrusions, slots and grooves, combination of thick and thin sections and general lack of symmetry, thermal and mechanical fatigue should be the primary failure mode.

2. Friction between hard aluminum-oxide layer on billet and iron-oxide layer on bearing causes hard wear problems.

3. Due to high temperatures and high extrusion speeds, plastice deformation should be expected.

1. In retrospect, brush paths are the most frequently repeated critical section and thus play a predominant role in fatigue failure.

1. It should be pointed out that the replacement of the die takes place after cleaning and repair have occurred many times. The part produced simply is too far out of dimension.

1. With uneven and unsymmetrical sections, and existing maximum pressure and friction, the die (bearing) is most likely to plastically deform.

1. Nitriding oven failures cause sub-optimal hardening or heat treatment of the die. This makes the die and bearing softer than is needed.

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IntroductionIntroduction Profile terminology / Die ProfilesProfile terminology / Die Profiles Overall and class-wise break-up of failure Overall and class-wise break-up of failure

modesmodes Various complexity failure analysisVarious complexity failure analysis Shape-wise breakdown of each failureShape-wise breakdown of each failure

modemode Conclusion / ReferencesConclusion / References

Types of Failure per Die TypeTypes of Failure per Die TypeType of Failure for Solid Dies

Fracture77%

Mixed2%

Deflection3%

Wear15%

Miscellaneous3%

Mandrel0%

Types of Failure for Hollow Dies

Fracture36%

Wear33%

Deflection7%

Mixed1%

Miscellaneous6%

Mandrel17%

Type of Failure for Semi-Hollow Dies

Fracture34%

Wear29%

Deflection29%

Mandrel3%

Mixed2%

Miscellaneous3%

1. Due to lack of mandrel, forces at the die are far less wear critical.

2. This would indicate lower heat of friction deformation.

1. Since a large majority of the hollow dies were simple in geometry, there was far less of a contribution due to fracture.

1. Since semi-hollow dies are a cross between a hollow and a solid die, the even contribution of failure should be expected.

OUTLINEOUTLINE

IntroductionIntroduction Profile terminology / Die ProfilesProfile terminology / Die Profiles Overall and class-wise break-up of failure Overall and class-wise break-up of failure

modesmodes Various complexity failure analysisVarious complexity failure analysis Shape-wise breakdown of each failureShape-wise breakdown of each failure

modemode Conclusion / ReferencesConclusion / References

Shape-WiseShape-Wise BreakdownBreakdownFracture Failure Occurance

Solid74%

Hollow14%

Semi-Hollow12%

Wear Failure Occurance

Solid25%

Hollow56%

Semi-Hollow19%

Plastic Deformation Occurance

Solid6%

Hollow68%

Semi-Hollow26%

Mixed Failure Occurance

Solid24%

Hollow69%

Semi-Hollow7%

Miscellaneous Failure Occurance

Solid58%

Hollow16%

Semi-Hollow26%

Mandrel Failure Occurance

Hollow82%

Semi-Hollow18%

1. Since contributions of the hollow and semi-hollow dies are almost equally smalll, it shows that the predominant failure for solid dies is fatigue fracture.

1. This confirms the previous conclusion that hollow dies fail primarily through wear.

2. Why are the solid and semi-hollow dies about the same even though one has a mandral and the other does not?

1. Additional friction, temperatures and forces at the bearing inlet due to the presence of the mandrel would indicate the large proportion of deflection failures in hollow dies.

OUTLINEOUTLINE

IntroductionIntroduction Profile terminology / Die ProfilesProfile terminology / Die Profiles Overall and class-wise break-up of failure Overall and class-wise break-up of failure

modesmodes Various complexity failure analysisVarious complexity failure analysis Shape-wise breakdown of each failureShape-wise breakdown of each failure

modemode Conclusion / ReferencesConclusion / References

ConclusionsConclusions

Testing supported the fact that the predominant failure Testing supported the fact that the predominant failure for solid dies is fatigue fracture.for solid dies is fatigue fracture.

Hollow dies fail primarily by wear.Hollow dies fail primarily by wear. Additional friction, temperatures and forces at the Additional friction, temperatures and forces at the

bearing inlet due to the presence of the mandrel and re-bearing inlet due to the presence of the mandrel and re-weld chambers in hollow dies are the reason for the weld chambers in hollow dies are the reason for the large proportion of deflection failures associated with large proportion of deflection failures associated with hollow dies.hollow dies.

Mixed mode failure is prevalent with hollow dies.Mixed mode failure is prevalent with hollow dies. Miscellaneous failure is predominant with solid dies.Miscellaneous failure is predominant with solid dies. Mandrel failure was obviously dominant in hollow dies.Mandrel failure was obviously dominant in hollow dies.

Flaws in Technical PaperFlaws in Technical Paper

Very few shape complexities were incorporated Very few shape complexities were incorporated in the study.in the study.

Only one material type die, and one material Only one material type die, and one material type billet was tested.type billet was tested.

Time line failure wasn’t included to incorporate Time line failure wasn’t included to incorporate the data with useful economics.the data with useful economics.

There variety of hollow dies used in the test There variety of hollow dies used in the test didn’t have many details, and could bias the test didn’t have many details, and could bias the test data.data.

RefrencesRefrences[1] I. Flitta, T. Sheppard, Nature of friction in extrusionprocess and it’s effect on material flow, Materials Scienceand Technology, December (2002) 837-846.[2] Dinesh Damodaran, Rajiv Shivpuri, Prediction andcontrol of part distortion during the hot extrusion oftitanium alloys, Journal of Materials Processing Technology, 150 (2004) 70-75.[3] Zubear Ahmed Khan, Uday Chakkingal, P. Venugopal,Analysis of forming loads, microstructure development andmechanical property evolution during equal channel angularextrusion of a commercial grade aluminum alloy, Journal ofMaterials Processing Technology, 135 (2003) 59-67.[4] S. Malayappan, R. Narayanasamy, Barrelling of aluminum solid cylinders during cold upset forging with constraint at one end, Materials Science and Technology, June (2002) 507-511.[5] S. C. V. Lim, M. Gupta, Enhancing modulus and Ductility of Mg/SiC composite through judicious selection of extrusion temperature and heat treatment, Materials Science and Technology, August (2002) 803-808.[6] Bruce Chalmers, Physical Metallurgy, 321-327, 332,1959, John Wiley and Sons.[7] F. J. Humphreys, W. S. Miller, M. R. Djazeb, Materials Science and Technology, (1990), 6, 1157-1166.

[8] M Gupta, R. Sikand, A.K. Gupta, Scr. Metallurgy Material, (1994), 30, 1343-1348.[9] M. C. Shaw and J. P. Avery, Forming limits – reliablilty,stress analysis and failure prevention methods in mechanicaldesign, ASME Centennial Bound Volume, 297-303, (1980),Century Publications.

Questions?Questions?