Introduction to Aluminum Alloys and Tempers

237 Pages·2000·5.81 MB·English

by  J. Gilbert Kaufman

© 2000 ASM International. All Rights Reserved. www.asminternational.org
Introduction to Aluminum Alloys and Tempers (#06180)
Introduction to Aluminum Alloys and
Tempers
J. Gilbert Kaufman
ASM International®
Materials Park, OH 44073-0002
www.asminternational.org
© 2000 ASM International. All Rights Reserved. www.asminternational.org
Introduction to Aluminum Alloys and Tempers (#06180)
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LibraryofCongressCataloging-in-PublicationData
Kaufman,J.G.(JohnGilbert),1931-
Introductontoaluminumalloysandtempers/J.GilbertKaufman.
p.cm.
Includesbibliographicalreferencesandindex.
1.Aluminumalloys.2.Metals—Heattreatment.I.Title.
TA480.A6K362000 620.1’86—dc21 00-056544
ISBN0-87170-689-X
SAN:204-7586
ASMInternational®
MaterialsPark,OH44073-0002
http://www.asminternational.org
PrintedintheUnitedStatesofAmerica
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Introduction to Aluminum Alloys and Tempers (#06180)
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
CHAPTER 1: Introduction: The Nature of the Problem . . . . . . . 1
The Keys to Understanding . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Characteristics of Wrought Aluminum Alloys . . . . . . . . . . . . . . .3
Characteristics of Cast Aluminum Alloys . . . . . . . . . . . . . . . . . .5
Definitions for Aluminum and Aluminum Alloys . . . . . . . . . . . . .5
Applications of Aluminum Alloys . . . . . . . . . . . . . . . . . . . . . . .7
Microscopy of Aluminum and Aluminum Alloys . . . . . . . . . . . . .7
Units and Unit Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
CHAPTER 2: Aluminum Alloy and Temper Designation
Systems of the Aluminum Association . . . . . . . . . . . . . . . . 9
Wrought Aluminum Alloy Designation System . . . . . . . . . . . . .10
Cast Aluminum Alloys Designation System . . . . . . . . . . . . . . .11
Designations for Experimental Aluminum Alloys . . . . . . . . . . . .16
Aluminum Alloy Temper Designation System . . . . . . . . . . . . . .16
Basic Temper Designations . . . . . . . . . . . . . . . . . . . . . . . . .16
Subdivisions of the Basic Tempers . . . . . . . . . . . . . . . . . . . .17
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
CHAPTER 3: Understanding Wrought and Cast
Aluminum Alloys Designations . . . . . . . . . . . . . . . . . . . . . 23
The Wrought Alloy Series . . . . . . . . . . . . . . . . . . . . . . . . . . .23
How the System is Applied . . . . . . . . . . . . . . . . . . . . . . . . .23
Principal Alloying Elements . . . . . . . . . . . . . . . . . . . . . . . .25
Understanding Wrought Alloy Strengthening
Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Understanding Wrought Alloy Advantages and
Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Other Characteristics Related to Principal Alloying
Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Understanding Wrought Alloy Variations . . . . . . . . . . . . . . . .30
Links to Earlier Alloy Designations . . . . . . . . . . . . . . . . . . .31
Unified Numbering System (UNS) Alloy Designation
System for Wrought Alloys . . . . . . . . . . . . . . . . . . . . . . .31
The Cast Alloy Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
iii
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Introduction to Aluminum Alloys and Tempers (#06180)
How the Current Aluminum Cast Alloy Designation
System is Applied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Understanding Cast Alloy Strengthening Mechanisms . . . . . . .33
Understanding Cast Alloy Advantages and Limitations . . . . . .34
Examples of the Use of Variations in Cast Alloy
Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Alloys for Different Casting Processes . . . . . . . . . . . . . . . . .35
Other Characteristics Related to Composition . . . . . . . . . . . .35
Evolution of the Aluminum Cast Alloy Designation
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
UNS Alloy Designation System for Cast Alloys . . . . . . . . . . .36
CHAPTER 4: Understanding the Aluminum Temper
Designation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Tempers for Wrought Aluminum Alloys . . . . . . . . . . . . . . . . . .39
Review of the Basic Tempers for Wrought Alloys . . . . . . . . .57
Subdivisions of the Basic Tempers . . . . . . . . . . . . . . . . . . . .60
Tempers Designating Residual Stress Relief of Heat
Treated Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
Temper Designations Identifying Modifications in
Quenching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
Designations Indicating Heat Treatment by User . . . . . . . . . .68
Tempers Identifying Additional Cold Work between
Quenching and Aging . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Tempers Identifying Additional Cold Work Following
Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Tempers Designating Special Corrosion-Resistant
Tempers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
Temper Designation for Special or Premium Properties . . . . . .71
Tempers for Cast Aluminum Alloys . . . . . . . . . . . . . . . . . . . . .73
Review of the Basic Tempers for Cast Alloys . . . . . . . . . . . .73
Subdivisions of the Basic Temper Types for
Cast Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
Importance to Understanding Aluminum Tempers . . . . . . . . . . .76
CHAPTER 5: Understanding Aluminum Fabricating
Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Ingot and Billet Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Strip and Slab Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Hot and Cold Rolling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Extrusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Forging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Cast Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
Permanent Mold Casting . . . . . . . . . . . . . . . . . . . . . . . . . . .80
Sand Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81
iv
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Introduction to Aluminum Alloys and Tempers (#06180)
Investment Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
Die Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Combinations of Casting and Forging . . . . . . . . . . . . . . . . . . .84
Heat Treatment of Aluminum Alloys . . . . . . . . . . . . . . . . . . . .84
CHAPTER 6: Applications for Aluminum Alloys and
Tempers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Applications by Alloy Class . . . . . . . . . . . . . . . . . . . . . . . . . .87
Wrought Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
Cast Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108
Applications by Market Area . . . . . . . . . . . . . . . . . . . . . . . . .115
Electrical Markets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
Building and Construction Markets . . . . . . . . . . . . . . . . . . .116
Transportation Applications . . . . . . . . . . . . . . . . . . . . . . . .116
Marine Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
Rail Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
Packaging Applications . . . . . . . . . . . . . . . . . . . . . . . . . . .118
Petroleum and Chemical Industry Components . . . . . . . . . . .118
Other Markets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118
CHAPTER 7: Representative Micrographs . . . . . . . . . . . . . . . 119
Wrought Aluminum Alloys . . . . . . . . . . . . . . . . . . . . . . . . . .120
Welded Wrought Aluminum Alloys . . . . . . . . . . . . . . . . . . . .153
Brazed Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162
Cast Aluminum Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164
Welded Cast Aluminum Alloys . . . . . . . . . . . . . . . . . . . . . . .181
Welded Wrought-To-Cast Alloys . . . . . . . . . . . . . . . . . . . . . .182
Welded Aluminum To Steel . . . . . . . . . . . . . . . . . . . . . . . . .184
Welded Aluminum to Copper . . . . . . . . . . . . . . . . . . . . . . . .184
CHAPTER 8: Selected References . . . . . . . . . . . . . . . . . . . . . 185
APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Alloy Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Cast Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .243
Wrought Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .248
v
© 2000 ASM International. All Rights Reserved. www.asminternational.org
Introduction to Aluminum Alloys and Tempers (#06180)
ASM International
Technical Books
Committee (1999-2000)
Sunniva R. Collins (Chair) Gordon Lippa
Swagelok/Nupro Company North Star Casteel
Eugen Abramovici Jacques Masounave
Bombadier Aerospace (Canadair) Université du Québec
A.S Brar Charles A. Parker (Vice Chair)
Seagate Technology Inc. AlliedSignal Aircraft Landing
Ngai Mun Chow Systems
Det Norske Veritas Pte Ltd. K. Bhanu Sankara Rao
Seetharama C. Deevi Indira Gandhi Centre for Atomic
Phillip Morris, USA Research
Bradley J. Diak Mel M. Schwartz
Queen’s University Sikorsky Aircraft Corporation
Dov B. Goldman (retired)
Precision World Products Peter F. Timmins
James F.R. Grochmal University College of the Fraser
Metallurgical Perspectives Valley
Nguyen P. Hung George F. Vander Voort
Nanyang Technological University Buehler Ltd.
Serope Kalpakjian
Illinois Institute of Technology
vi
© 2000 ASM International. All Rights Reserved. www.asminternational.org
Introduction to Aluminum Alloys and Tempers (#06180)
Preface
The idea for this timely reference book was originally suggested by
Tom Croucher, a California-based consulting metallurgist. Dr. Croucher
andHarryChandlerofASMInternationalprovidedinputforthefirstdraft
version.Ibroadeneditoutsubstantiallytocovertheunderstandingofthe
advantages and limitations of aluminum alloy/temper combinations in
terms of the relationship of their composition, process history, and
microstructure to service requirements.
I would like to acknowledge Dr. John A. S. Green and the Aluminum
Association, Inc. for making available critically important material for
inclusion in this book. Among the Aluminum Association publications
used as key references, notably on the alloy and temper designation
system and aluminum terminology, were the following:
O Aluminum Standards and Data
O Standards for Aluminum Sand and Permanent Mold Castings
O Aluminum: Technology, Applications, and Environment
More complete citations to these and other reference materials are given
in the Selected References, Chapter 8.
Among the ASM International books used as major sources, most
notably for micrographs, are the following:
O HeatTreater’sGuide:PracticesandProceduresforNonferrousAlloys
O ASM Specialty Handbook: Aluminum and Aluminum Alloys
Finally, I want to acknowledge the publications of the American
Foundrymen’s Society, Inc. and the Diecasting Development Council,
whose publications Aluminum Casting Technology and Product Design
for Die Casting, respectively, provided excellent resources for casting
terminology and descriptions of casting procedures.
J. Gilbert Kaufman
Columbus, Ohio
vii
Introduction to Aluminum Alloys and Tempers Copyright © 2000 ASM International®
J. Gilbert Kaufman, p1-8 All rights reserved.
DOI:10.1361/iaat2000p001 www.asminternational.org
1
CHAPTER
Introduction: The
Nature of the Problem
THENEEDFORTHISBOOKstemsdirectlyfromtheincreasinguse
ofaluminumandaluminumalloysinautomobilesandagreatvarietyof
other products that we encounter in everyday living. The excellent
combinationoflightweight,highstrength,greatcorrosionresistance,and
reasonable cost has made aluminum and its alloys one of the most
commonly used metal groups. Whereas weight saving by substituting
light metals for heavy metals has been standard practice for generations
incriticalaerospacestructures,ithasnowreachedtopprioritystatusina
variety of other industries, including those manufacturing cars, trucks,
military vehicles, aviation ground support vehicles, munitions, building
and highway structures, and construction equipment.
Thetransitionfromheretoforemorewidelyusedironandsteelcanbe
especially difficult for those with little or no experience with aluminum
andaluminumalloys.Ofnecessity,theymustbecomeconversantwitha
newalloydesignationsystemand,perhapsevenmoreimportantly,witha
greatnumberandvarietyoftempers,thedesignationsforwhichprovide
backgroundonhowthealloyshavebeenproducedtoobtainthedesired
properties and characteristics.
The positive news is twofold. First, contrary to the case for other
metals, there are widely accepted alloy and temper designation systems
foraluminum,createdandmaintainedbytheAluminumAssociation,that
areusedthroughoutthealuminumindustry.Thosesystemsarepublished
intheAluminumAssociationpublicationAluminumStandardsandData
(see Chapter 8, “Selected References”) and are recognized by the
AmericanNationalStandardsInstitute(ANSI)astheAmericanNational
Standard Alloy and Temper Designation Systems for Aluminum (see
Chapter 8). The second item of positive news is that, with a little
concentration, the aluminum alloy and temper designation systems are
consistent, logical, and easily understood.
2/IntroductiontoAluminumAlloysandTempers
TheAluminumAssociationmaintainsthealloyandtemperdesignations
systemsand, infact, isaccreditedbyANSItocarryout thisroleforthe
United States. The procedures for registering alloys and tempers, and a
record of the alloys and tempers registered, are published in Alloy and
TemperRegistrationRecords(seeChapter8)andareavailableatminimal
cost for any producer or user to track. Further, standard aluminum
tempersthathavebeenregisteredwiththeAluminumAssociationandare
in widest use are described in Aluminum Standards and Data.
An additional complication to be dealt with is the fact that, typically,
each country around the world has its own designations system for
aluminum alloys and tempers. Fortunately, great progress is being made
in improving that situation, and the Aluminum Association’s alloy
designation system is now recognized by about 90% of the world’s
aluminumindustry.ThepublicationRecommendation:InternationalDes-
ignation System for Wrought Aluminum and Wrought Aluminum Alloys
(see Chapter 8) has been accepted almost universally, and progress is
slowlybeingmadeinbroadeningtheagreementtocastalloysandcertain
basic temper designations as well. Regrettably, however, experience
indicates that full acceptance of universal equivalents has not yet been
completed, and situations requiring producers and buyers to discuss
clarifications can still occur.
The Keys to Understanding
Thus, the principal keys to gaining a good introduction to aluminum
alloys and tempers are knowledge and understanding of the alloy and
temperdesignationssystemsthemselves.Themainmissionofthisbook
is to build upon the information available in sources such as The
Aluminum Association Alloy and Temper Registration Records and
AluminumStandardsandDatatoshedmorelightandunderstandingon
the characteristics, production technology, and applications for the most
commonly used aluminum alloys and tempers.
To accomplish this, the basic aluminum alloy and temper designation
systems,asdevelopedbytheAluminumAssociationanddocumentedin
AluminumStandardsandDataandANSIH35.1,arepresentedinChapter
2.Chapter3explainsthealloydesignationsystemingreaterdetailwith
examples, and Chapter 4 covers the temper designation system in a
similarmanner.Theprocessesusedtoproducealuminumalloyproducts
are described briefly in Chapter 5, and representative applications are
described in Chapter 6.
We want to emphasize that the real authority on aluminum alloys and
tempers is the Aluminum Association Technical Committee on Product
Standards (TCPS), the group that, on behalf of theAluminumAssocia-
Introduction:TheNatureoftheProblem /3
tion, maintains the alloy and temper designation systems and registers
new alloys and tempers as they come along. At times, there is an
unfortunate tendency on the part of some producers and fabricators to
intentionally or unintentionally create their own designations for alumi-
numalloysandtempersandtodosoinastylethatmisleadinglysuggests
thatthenewlycreateddesignationshavebeenrecognizedbytheindustry
as a whole through the registration process. This is unethical and
improperbecauseitmisleadsproducersandusersalikeastotheheritage
of the designation and dilutes the value of systems based on uniformity
andindustrystandards.Theindependentcreationofeitheralloyortemper
designations without the complete registration process defined by the
AluminumAssociation andANSI H35.1 is to be avoided.
Any questions or decisions needed on existing or new registrations
should be directed to that group at the following address:
AluminumAssociationTechnical Committee on Product Standards
TheAluminumAssociation, Inc.
900 Nineteenth Street, NW, Suite 300
Washington, DC 20006
Wewanttoemphasizethatthemissionofthispublicationistoprovide
abriefintroductiontoaluminumalloys,includingtheirapplications.For
moredetailonthevariousaspectsofthissubject,readersareencouraged
toconsulttheselectedreferencesinChapter8,particularlythecomplete
treatise on the aluminum industry by D.G.Altenpohl, Aluminum: Tech-
nology,Applications, and Environment.
Characteristics of Wrought Aluminum Alloys
It is appropriate to briefly note at this stage some of the basic
characteristics of wrought aluminum alloys that make them desirable
candidatesforawiderangeofapplications.Wroughtalloysareaddressed
first, then cast alloys.
CorrosionResistance. Asaresultofanaturallyoccurringtenacious
surfaceoxidefilm,manyaluminumalloysprovideexceptionalresistance
tocorrosioninmanyatmosphericandchemicalenvironments.Alloysof
the 1xxx, 3xxx, 5xxx, and 6xxx systems are especially favorable in this
respectandareevenusedinapplicationswheretheyareindirectcontact
with seawater and antiskid salts.
Thermal Conductivity. Aluminum and aluminum alloys are good
conductorsofheat,andwhiletheymeltatlowertemperaturesthansteels,
approximately535°C(1000°F).Theyareslowerthansteeltoreachvery
high temperatures in fire exposure.