steel heat treatment handboook-metalluurgy and technologies
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Preface
The first edition of the Steel Heat Treatment Handbook was initially released in 1997. The
objective of that book was to provide the reader with well-referenced information on the
subjects covered with sufficient depth and breadth to serve as either an advanced under-
graduate or graduate level text on heat treatment or as a continuing handbook reference for
the designer or practicing engineer. However, since the initial release of the first edition of the
Steel Heat Treatment Handbook, there have been various advancements in the field that
needed to be addressed to assure up-to-date coverage of the topic. This text, Steel Heat
Treatment: Metallurgy and Technologies, is part of a revision of the earlier text. Some of the
chapters in this text are updated revisions of the earlier book and others are completely new
chapters or revisions. These chapters include:
Chapter 1. Steel Nomenclature (Revision)
Chapter 2. Classification and Mechanisms of Steel Transformations (New Chapter)
Chapter 3. Fundamental Concepts in Steel Heat Treatment (Minor Revisions)
Chapter 4. Effects of Alloying Elements on the Heat Treatment of Steel (Minor Revisions)
Chapter 5. Hardenability (Minor Revisions)
Chapter 6. Steel Heat Treatment (Minor Revisions)
Chapter 7. Heat Treatment with Gaseous Atmospheres (Revision)
Chapter 8. Nitriding Techniques, Ferritic Nitrocarburizing, and Austenitic Nitrocarburiz-
ing Techniques and Methods (Revision)
Chapter 9. Quenching and Quenching Technology (Revision)
Chapter 10. Distortion of Heat-Treated Components (New Chapter)
Chapter 11. Tool Steels (New Chapter)
Chapter 12. Stainless Steel Heat Treatment (New Chapter)
Chapter 13. Heat Treatment of Powder Metallurgy Steel Components (New Chapter)
Approximately a third of the book is new and a third of the book is significantly revised
versus the first edition of the Steel Heat Treatment Handbook. This new text is current with
respect to heat treatment technology at this point at the beginning of the 21st century and is
considerably broader in coverage but with the same depth and thoroughness that character-
ized the first edition.
Unfortunately, my close friend, colleague and mentor, Dr. Maurice A.H. Howes, who
helped to bring the first edition of Steel Heat Treatment Handbook into fruition was unable to
assist in the preparation of this second edition. However, I have endeavored to keep the same
consistency and rigor of coverage as well as be true to the original vision that we had for this
text as a way of serving the heat treatment industry so that this book will be a value resource
to the reader in the future.
George E. Totten, Ph.D., FASM
Portland State University
Portland, Oregon
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Editor
George E. Totten, Ph.D. is president of G.E. Totten & Associates, LLC in Seattle, Washing-
ton and a visiting professor of materials science at Portland State University. He is coeditor of
a number of books including Steel Heat Treatment Handbook, Handbook of Aluminum,
Handbook of Hydraulic Fluid Technology, Mechanical Tribology, and Surface Modification
and Mechanisms (all titles of CRC Press), as well as the author or coauthor of over 400
technical papers, patents, and books on lubrication, hydraulics, and thermal processing. He is
a Fellow of ASM International, SAE International, and the International Federation for
Heat Treatment and Surface Engineering (IFHTSE), and a member of other professional
organizations including ACS, ASME, and ASTM. He formerly served as president of
IFHTSE. He earned B.S. and M.S. degrees from Fairleigh Dickinson University, Teaneck,
New Jersey and a Ph.D. degree from New York University, New York.
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Contributors
S.S. Babu
Edison Welding Institute
Columbus, Ohio
Elhachmi Essadiqi
CANMET, Materials Technology
Laboratory
Ottawa, ON, Canada
Johann Grosch
Institut fuer Werkstofftechnik
Technische Universitaet
Berlin, Germany
Bozidar Liscic
Faculty of Mechanical Engineering and
Naval Architecture
University of Zabreb
Zabreb, Croatia
Guoquan Liu
Beijing University of Science and Technology
Beijing, China
Michiharu Narazaki
Utsunomiya University
Utsunomiya, Japan
Arnold R. Ness
Bradley University
Peoria, Illinois
Joseph W. Newkirk
University of Missouri-Rolla,
Rolla, Missouri
Angelo Fernando Padilha
University of Sao Paulo
Sao Paulo, Brazil
Ronald Lesley Plaut
University of Sao Paulo
Sao Paulo, Brazil
David Pye
Pye Metallurgical Consulting, Inc.
Meadville, Pennsylvania
Paulo Rangel Rios
Fluminense Federal University
V. Redonda, Brazil
Anil Kumar Sinha
AKS Associates
Fort Wayne, Indiana
Anton Stich
Technical University of Munich
Munich, Germany
Alexey V. Sverdlin
Bradley University
Peoria, Illinois
Hans M. Tensi
Technical University of Munich
Munich, Germany
Sanjay N. Thakur
Hazen Powder Parts, LLC
Hazen, Arkansas
George E. Totten
Portland State University
Portland, Oregon
Chengjian Wu
Beijing University of Science and Technology
Beijing, China
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Contents
Chapter 1 Steel Nomenclature .............................................................................................1
Anil Kumar Sinha, Chengjian Wu, and Guoquan Liu
Chapter 2 Classification and Mechanisms of Steel Transformation .................................91
S.S. Babu
Chapter 3 Fundamental Concepts in Steel Heat Treatment ............................................ 121
Alexey V. Sverdlin and Arnold R. Ness
Chapter 4 Effects of Alloying Elements on the Heat Treatment of Steel ........................ 165
Alexey V. Sverdlin and Arnold R. Ness
Chapter 5 Hardenability ..................................................................................................213
Bozidar Liscic
Chapter 6 Steel Heat Treatment ......................................................................................277
Bozidar Liscic
Chapter 7 Heat Treatment with Gaseous Atmospheres...................................................415
Johann Grosch
Chapter 8 Nitriding Techniques, Ferritic Nitrocarburizing, and
Austenitic Nitrocarburizing Techniques and Methods ................................... 475
David Pye
Chapter 9 Quenching and Quenching Technology ..........................................................539
Hans M. Tensi, Anton Stich, and George E. Totten
Chapter 10 Distortion of Heat-Treated Components ...................................................... 607
Michiharu Narazaki and George E. Totten
Chapter 11 Tool Steels .....................................................................................................651
Elhachmi Essadiqi
Chapter 12 Stainless Steel Heat Treatment ...................................................................... 695
Angelo Fernando Padilha, Ronald Lesley Plaut, and Paulo Rangel Rios
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Chapter 13 Heat Treatment of Powder Metallurgy Steel Components ...........................741
Joseph W. Newkirk and Sanjay N. Thakur
Appendices
Appendix 1 Common Conversion Constants ................................................................ 789
Appendix 2 Temperature Conversion Table .................................................................. 791
Appendix 3 Volume Conversion Table .......................................................................... 801
Appendix 4 Hardness Conversion Tables: Hardened Steel and Hard Alloys ................ 803
Appendix 5 Recommended MIL 6875 Specification Steel Heat
Treatment Conditions ................................................................................805
Appendix 6 Colors of Hardening and Tempering Heats ...............................................815
Appendix 7 Weight Tables for Steel Bars ......................................................................817
Index...................................................................................................................................821
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1 Steel NomenclatureAnil Kumar Sinha, Chengjian Wu, and Guoquan Liu
CONTENTS
1.1 Introduction .................................................................................................................. 2
1.2 Effects of Alloying Elements......................................................................................... 2
1.2.1 Carbon.............................................................................................................. 3
1.2.2 Manganese ........................................................................................................ 3
1.2.3 Silicon ............................................................................................................... 4
1.2.4 Phosphorus ....................................................................................................... 4
1.2.5 Sulfur ................................................................................................................ 4
1.2.6 Aluminum......................................................................................................... 5
1.2.7 Nitrogen............................................................................................................ 5
1.2.8 Chromium......................................................................................................... 5
1.2.9 Nickel................................................................................................................ 5
1.2.10 Molybdenum..................................................................................................... 5
1.2.11 Tungsten ........................................................................................................... 6
1.2.12 Vanadium ......................................................................................................... 6
1.2.13 Niobium and Tantalum .................................................................................... 6
1.2.14 Titanium ........................................................................................................... 6
1.2.15 Rare Earth Metals ............................................................................................ 7
1.2.16 Cobalt ............................................................................................................... 7
1.2.17 Copper .............................................................................................................. 7
1.2.18 Boron................................................................................................................ 7
1.2.19 Zirconium ......................................................................................................... 8
1.2.20 Lead.................................................................................................................. 8
1.2.21 Tin .................................................................................................................... 8
1.2.22 Antimony.......................................................................................................... 8
1.2.23 Calcium............................................................................................................. 8
1.3 Classification of Steels .................................................................................................. 8
1.3.1 Types of Steels Based on Deoxidation Practice.................................................. 9
1.3.1.1 Killed Steels.......................................................................................... 9
1.3.1.2 Semikilled Steels ................................................................................. 10
1.3.1.3 Rimmed Steels.................................................................................... 10
1.3.1.4 Capped Steels ..................................................................................... 11
1.3.2 Quality Descriptors and Classifications............................................................ 11
1.3.3 Classification of Steel Based on Chemical Composition .................................. 13
1.3.3.1 Carbon and CarbonManganese Steels ............................................. 13
1.3.3.2 Low-Alloy Steels ................................................................................ 17
1.3.3.3 High-Strength Low-Alloy Steels ........................................................ 24
1.3.3.4 Tool Steels.......................................................................................... 27
1.3.3.5 Stainless Steels.................................................................................... 33
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1.3.3.6 Maraging Steels.................................................................................. 44
1.4 Designations for Steels................................................................................................ 45
1.4.1 SAE-AISI Designations.................................................................................... 46
1.4.1.1 Carbon and Alloy Steels .................................................................... 46
1.4.1.2 HSLA Steels ....................................................................................... 47
1.4.1.3 Formerly Listed SAE Steels ............................................................... 47
1.4.2 UNS Designations ............................................................................................ 47
1.5 Specifications for Steels............................................................................................... 50
1.5.1 ASTM (ASME) Specifications ......................................................................... 50
1.5.2 AMS Specifications .......................................................................................... 51
1.5.3 Military and Federal Specifications.................................................................. 51
1.5.4 API Specifications ............................................................................................ 54
1.5.5 ANSI Specifications.......................................................................................... 66
1.5.6 AWS Specifications .......................................................................................... 66
1.6 International Specifications and Designations............................................................ 66
1.6.1 ISO Designations.............................................................................................. 66
1.6.1.1 The Designation for Steels with Yield Strength ................................. 66
1.6.1.2 The Designation for Steels with Chemical Composition.................... 84
1.6.2 GB Designations (State Standards of China) ................................................... 85
1.6.3 DIN Standards ................................................................................................. 86
1.6.4 JIS Standards.................................................................................................... 86
1.6.5 BS Standards .................................................................................................... 86
1.6.6 AFNOR Standards........................................................................................... 86
References ........................................................................................................................... 87
1.1 INTRODUCTION
According to the ironcarbon phase diagram [13], all binary FeC alloys containing less than
about 2.11 wt% carbon* are classified as steels, and all those containing higher carbon content
are termed cast iron. When alloying elements are added to obtain the desired properties, the
carbon content used to distinguish steels from cast iron would vary from 2.11 wt%.
Steels are the most complex and widely used engineering materials because of (1)
the abundance of iron in the Earths crust, (2) the high melting temperature of iron
(15348C), (3) a range of mechanical properties, such as moderate (200300 MPa) yieldstrength with excellent ductility to in excess of 1400 MPa yield stress with fracture toughness
up to 100 MPa m2, and (4) associated microstructures produced by solid-state phase trans-formations by varying the cooling rate from the austenitic condition [4].
This chapter describes the effects of alloying elements on the properties and characteristics
of steels, reviews the various systems used to classify steels, and provides extensive tabular
data relating to the designation of steels.
1.2 EFFECTS OF ALLOYING ELEMENTS
Steels contain alloying elements and impurities that must be associated with austenite, ferrite,
and cementite. The combined effects of alloying elements and heat treatment produce an
enormous variety of microstructures and properties. Given the limited scope of this chapter, it
*This figure varies slightly depending on the source. It is commonly taken as 2.11wt% [1] or 2.06wt% [2], while it is
calculated thermodynamically as 2.14wt% [3].
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would be difficult to include a detailed survey of the effects of alloying elements on the iron
carbon equilibrium diagram, allotropic transformations, and forming of new phases. This
complicated subject, which lies in the domain of ferrous physical metallurgy, has been
reviewed extensively in Chapter 2 of this handbook and elsewhere in the literature [4,5,812].
In this section, the effects of various elements on steelmaking (deoxidation) practices and
steel characteristics will be briefly outlined. It should be noted that the effects of a single
alloying element on either practice or characteristics is modified by the influence of other
elements. The interaction of alloying elements must be considered [5].
According to the effect on matrix, alloying elements can be divided into two categories:
1. By expending the g-field, and encouraging the formation of austenite, such as Ni, Co,Mn, Cu, C, and N (these elements are called austenite stabilizers)
2. By contracting the g-field, and encouraging the formation of ferrite, such as Si, Cr, W,Mo, P, Al, Sn, Sb, As, Zr, Nb, B, S, and Ce (these elements are called ferrite
stabilizers)
Alloying elements can be divided into two categories according to the interaction with
carbon in steel:
1. Carbide-forming elements, such as Mn, Cr, Mo, W, V, Nb, Ti, and Zr. They go into
solid solution in cementite at low concentrations. At higher concentrations, they form
more stable alloy carbides, though Mn only dissolves in cementite.
2. Noncarbide-forming elements, such as Ni, Co, Cu, Si, P, and Al. They are free from
carbide in steels, and normally found in the matrix [5,11,12].
To simplify the discussion, the effects of various alloying elements listed below are
summarized separately.
1.2.1 CARBON
The amount of carbon (C) required in the finished steel limits the type of steel that can be made.
As the C content of rimmed steels increases, surface quality deteriorates. Killed steels in the
approximate range of 0.150.30% C may have poorer surface quality and require special
processing to attain surface quality comparable to steels with higher or lower C contents.
Carbon has a moderate tendency for macrosegregation during solidification, and it is
often more significant than that of any other alloying elements. Carbon has a strong tendency
to segregate at the defects in steels (such as grain boundaries and dislocations). Carbide-
forming elements may interact with carbon and form alloy carbides. Carbon is the main
hardening element in all steels except the austenitic precipitation hardening (PH) stainless
steels, managing steels, and interstitial-free (IF) steels. The strengthening effect of C in steels
consists of solid solution strengthening and carbide dispersion strengthening. As the C
content in steel increases, strength increases, but ductility and weldability decrease [4,5].
1.2.2 MANGANESE
Manganese (Mn) is present in virtually all steels in amounts of 0.30% or more [13]. Manga-
nese is essentially a deoxidizer and a desulfurizer [14]. It has a lesser tendency for macro-
segregation than any of the common elements. Steels above 0.60% Mn cannot be readily
rimmed. Manganese is beneficial to surface quality in all carbon ranges (with the exception of
extremely low-carbon rimmed steels) and reduction in the risk of red-shortness. Manganese
favorably affects forgeability and weldability.
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Manganese is a weak carbide former, only dissolving in cementite, and forms alloying
cementite in steels [5]. Manganese is an austenite former as a result of the open g-phase field.Large quantities (>2% Mn) result in an increased tendency toward cracking and distortionduring quenching [4,5,15]. The presence of alloying element Mn in steels enhances the
impurities such as P, Sn, Sb, and As segregating to grain boundaries and induces temper
embrittlement [5].
1.2.3 SILICON
Silicon (Si) is one of the principal deoxidizers used in steelmaking; therefore, silicon content
also determines the type of steel produced. Killed carbon steels may contain Si up to a
maximum of 0.60%. Semikilled steels may contain moderate amounts of Si. For example,
in rimmed steel, the Si content is generally less than 0.10%.
Silicon dissolves completely in ferrite, when silicon content is below 0.30%, increasing its
strength without greatly decreasing ductility. Beyond 0.40% Si, a marked decrease in ductility
is noticed in plain carbon steels [4].
If combined with Mn or Mo, silicon may produce greater hardenability of steels [5]. Due
to the addition of Si, stress corrosion can be eliminated in CrNi austenitic steels. In heat-
treated steels, Si is an important alloy element, and increases hardenability, wear resistance,
elastic limit and yield strength, and scale resistance in heat-resistant steels [5,15]. Si is a
noncarbide former, and free from cementite or carbides; it dissolves in martensite and retards
the decomposition of alloying martensite up to 3008C.
1.2.4 PHOSPHORUS
Phosphorus (P) segregates during solidification, but to a lesser extent than C and S. Phos-
phorus dissolves in ferrite and increases the strength of steels. As the amount of P increases,
the ductility and impact toughness of steels decrease, and raises the cold-shortness [4,5].
Phosphorus has a very strong tendency to segregate at the grain boundaries, and causes
the temper embrittlement of alloying steels, especially in Mn, Cr, MnSi, CrNi, and CrMn
steels. Phosphorus also increases the hardenability and retards the decomposition of
martensite-like Si in steels [5]. High P content is often specified in low-carbon free-machining
steels to improve machinability. In low-alloy structural steels containing ~0.1% C, P increases
strength and atmospheric corrosion resistance. In austenitic CrNi steels, the addition of P
can cause precipitation effects and an increase in yield points [15]. In strong oxidizing agent, P
causes grain boundary corrosion in austenitic stainless steels after solid solution treatment as
a result of the segregation of P at grain boundaries [5].
1.2.5 SULFUR
Increased amounts of sulfur (S) can cause red- or hot-shortness due to the low-melting sulfide
eutectics surrounding the grain in reticular fashion [15,16]. Sulfur has a detrimental effect on
transverse ductility, notch impact toughness, weldability, and surface quality (particularly in
the lower carbon and lower manganese steels), but has a slight effect on longitudinal
mechanical properties.
Sulfur has a very strong tendency to segregate at grain boundaries and causes reduction of
hot ductility in alloy steels. However, sulfur in the range of 0.080.33% is intentionally added
to free-machining steels for increased machinability [5,17] .
Sulfur improves the fatigue life of bearing steels [18], because (1) the thermal
coefficient on MnS inclusion is higher than that of matrix, but the thermal coefficient of
oxide inclusions is lower than that of matrix, (2) MnS inclusions coat or cover oxides (such as
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alumina, silicate, and spinel), thereby reducing the tensile stresses in the surrounding matrix
[5,10,19].
1.2.6 ALUMINUM
Aluminum (Al) is widely used as a deoxidizer and a grain refiner [9]. As Al forms very hard
nitrides with nitrogen, it is usually an alloying element in nitriding steels. It increases scaling
resistance and is therefore often added to heat-resistant steels and alloys. In precipitation-
hardening stainless steels, Al can be used as an alloying element, causing precipitation-
hardening reaction. Aluminum is also used in maraging steels. Aluminum increases the
corrosion resistance in low-carbon corrosion-resisting steels. Of all the alloying elements, Al
is one of the most effective elements in controlling grain growth prior to quenching.
Aluminum has the drawback of a tendency to promote graphitization.
1.2.7 NITROGEN
Nitrogen (N) is one of the important elements in expanded g-field group. It can expand andstabilize the austenitic structure, and partly substitute Ni in austenitic steels. If the nitride-
forming elements V, Nb, and Ti are added to high-strength low-alloy (HSLA) steels, fine
nitrides and carbonitrides will form during controlled rolling and controlled cooling. Nitro-
gen can be used as an alloying element in microalloying steels or austenitic stainless steels,
causing precipitation or solid solution strengthening [5]. Nitrogen induces strain aging,
quench aging, and blue brittleness in low-carbon steels.
1.2.8 CHROMIUM
Chromium (Cr) is a medium carbide former. In the low Cr/C ratio range, only alloyed cementite
(Fe,Cr)3C forms. If the Cr/C ratio rises, chromium carbides (Cr,Fe)7C3 or (Cr,Fe)23C6 or both,
would appear. Chromium increases hardenability, corrosion and oxidation resistance of steels,
improves high-temperature strength and high-pressure hydrogenation properties, and enhances
abrasion resistance in high-carbon grades. Chromium carbides are hard and wear-resistant and
increase the edge-holding quality. Complex chromiumiron carbides slowly go into solution in
austenite; therefore, a longer time at temperature is necessary to allow solution to take place
before quenching is accomplished [5,6,14]. Chromium is the most important alloying element in
steels. The addition of Cr in steels enhances the impurities, such as P, Sn, Sb, and As, segregating
to grain boundaries and induces temper embrittlement.
1.2.9 NICKEL
Nickel (Ni) is a noncarbide-forming element in steels. As a result of the open g-phase field, Niis an austenite-forming element [5,11,15]. Nickel raises hardenability. In combination with Ni,
Cr and Mo, it produce greater hardenability, impact toughness, and fatigue resistance in
steels [5,10,11,18]. Nickel dissolving in ferrite improves toughness, decreases FATT50% (8C),even at the subzero temperatures [20]. Nickel raises the corrosion resistance of CrNi
austenitic stainless steels in nonoxidizing acid medium.
1.2.10 MOLYBDENUM
Molybdenum (Mo) is a pronounced carbide former. It dissolves slightly in cementite, while
molybdenum carbides will form when the Mo content in steel is high enough. Molybdenum
can induce secondary hardening during the tempering of quenched steels and improves the
creep strength of low-alloy steels at elevated temperatures.
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The addition of Mo produces fine-grained steels, increases hardenability, and improves
fatigue strength. Alloy steels containing 0.200.40% Mo or V display a delayed temper
embrittlement, but cannot eliminate it. Molybdenum increases corrosion resistance and is
used to a great extent in high-alloy Cr ferritic stainless steels and with CrNi austenitic
stainless steels. High Mo contents reduce the stainless steels susceptibility to pitting [5,15].
Molybdenum has a very strong solid solution strengthening in austenitic alloys at elevated
temperatures. Molybdenum is a very important alloying element for alloy steels.
1.2.11 TUNGSTEN
Tungsten (W) is a strong carbide former. The behavior of W is very similar to Mo in steels.
Tungsten slightly dissolves in cementite. As the content of W increases in alloy steels, W forms
very hard, abrasion-resistant carbides, and can induce secondary hardening during the
tempering of quenched steels. It promotes hot strength and red-hardness and thus cutting
ability. It prevents grain growth at high temperature. W and Mo are the main alloying
elements in high-speed steels [5,13]. However, W and Mo impair scaling resistance.
1.2.12 VANADIUM
Vanadium (V) is a very strong carbide former. Very small amounts of V dissolve in cementite.
It dissolves in austenite, strongly increasing hardenability, but the undissolved vanadium
carbides decrease hardenability [5]. Vanadium is a grain refiner, and imparts strength and
toughness. Fine vanadium carbides and nitrides give a strong dispersion hardening effect in
microalloyed steels after controlled rolling and controlled cooling. Vanadium provides a very
strong secondary hardening effect on tempering, therefore it raises hot-hardness and thus
cutting ability in high-speed steels. Vanadium increases fatigue strength and improves notch
sensitivity.
Vanadium increases wear resistance, edge-holding quality, and high-temperature strength.
It is therefore used mainly as an additional alloying element in high-speed, hot-forging, and
creep-resistant steels. It promotes the weldability of heat-treatable steels. The presence of V
retards the rate of tempering embrittlement in Mo-bearing steels.
1.2.13 NIOBIUM AND TANTALUM
Niobium (Nb) and tantalum (Ta) are very strong carbide and nitride formers. Small amounts
of Nb can form fine nitrides or carbonitrides and refine the grains, therefore increasing the
yield strength of steels. Niobium is widely used in microalloying steels to obtain high strength
and good toughness through controlled rolling and controlled cooling practices. A 0.03% Nb
in austenite can increase the yield strength of medium-carbon steel by 150 MPa. Niobium-
containing nonquenched and tempered steels, including microalloyed medium-carbon steels
and low-carbon bainite (martensite) steels, offer a greatly improved combination of strength
and toughness. Niobium is a stabilizer in CrNi austenitic steels to eliminate intergranular
corrosion.
1.2.14 TITANIUM
Titanium (Ti) is a very strong carbide and nitride former. The effects of Ti are similar to those
of Nb and V, but titanium carbides and nitrides are more stable than those of Nb and V. It is
widely used in austenitic stainless steels as a carbide former for stabilization to eliminate
intergranular corrosion. By the addition of Ti, intermetallic compounds are formed in
maraging steels, causing age hardening. Titanium increases creep rupture strength through
formation of special nitrides and tends significantly to segregation and banding [15].
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Ti, Nb, and V are effective grain inhibitors because their nitrides and carbides are quite
stable and difficult to dissolve in austenite. If Ti, Nb, and V dissolve in austenite, the
hardenability of alloy steels may increase strongly due to the presence of Mn and Cr in steels.
Mn and Cr decrease the stability of Ti-, Nb-, and V-carbides in steels [5].
1.2.15 RARE EARTH METALS
Rare earth metals (REMs) constitute the IIIB group of 17 elements in the periodic table. They are
scandium (Sc) of the fourth period, yttrium (Y) of the fifth period, and the lanthanides of the sixth
period, which include the elements, lanthanum (La), cerium (Ce), praseodymium (Pr), neodym-
ium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb),
dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm; Tu), ytterbium (Yb), and lutecium
(or lutecium, Lu). Their chemical and physical properties are similar. They generally coexist and
are difficult to separate in ore beneficiation and metal extraction so they are usually supplied as a
mixture and used in various mixture states in metallurgical industries. REMs are strong deox-
idizers and desulfurizers, and they also react with the low-melting elements, such as antimony
(Sb), tin (Sn), arsenic (As), and phosphorus (P), forming high-melting compounds and prevent-
ing them from causing the red-shortness and temper embrittlement [21,22]. The effects of REM
on shape control and modification of inclusions would improve transversal plasticity and
toughness, hot ductility, fatigue strength, and machinability. REMs tend strongly to segregate
at the grain boundaries and increase the hardenability of steels [21,23].
1.2.16 COBALT
Cobalt (Co) is a noncarbide former in steels. It decreases hardenability of carbon steels, but
by addition of Cr, it increases hardenability of CrMo alloy steels. Cobalt raises the marten-
sitic transformation temperature of Ms (8C) and decreases the amount of retained austenite inalloy steels. Cobalt promotes the precipitation hardening [5]. It inhibits grain growth at
high temperature and significantly improves the retention of temper and high-temperature
strength, resulting in an increase in tool life. The use of Co is generally restricted to high-speed
steels, hot-forming tool steels, maraging steels, and creep-resistant and high-temperature
materials [13,15].
1.2.17 COPPER
Copper (Cu) addition has a moderate tendency to segregate. Above 0.30% Cu can cause
precipitation hardening. It increases hardenability. If Cu is present in appreciable amounts,
it is detrimental to hot-working operations. It is detrimental to surface quality and exaggerates
the surface defects inherent in resulfurized steels. However, Cu improves the atmospheric
corrosion resistance (when in excess of 0.20%) and the tensile properties in alloy and low-alloy
steels, and reportedly helps the adhesion of paint [6,14]. In austenitic stainless steels, a Cu
content above 1% results in improved resistance to H2SO4 and HCl and stress corrosion [5,15].
1.2.18 BORON
Boron (B), in very small amounts (0.00050.0035%), has a starting effect on the hardenability
of steels due to the strong tendency to segregate at grain boundaries. The segregation of B in
steels is a nonequilibrium segregation. It also improves the hardenability of other alloying
elements. It is used as a very economical substitute for some of the more expensive elements.
The beneficial effects of B are only apparent with lower- and medium-carbon steels, with no
real increase in hardenability above 0.6% C [14]. The weldability of boron-alloyed steels is
another reason for their use. However, large amounts of B result in brittle, unworkable steels.
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 7 17.8.2006 4:37pm
Steel Nomenclature 7
-
1.2.19 ZIRCONIUM
Zirconium (Zr) is added to killed HSLA steels to obtain improvement in inclusion charac-
teristics, particularly sulfide inclusions, where modifications of inclusion shape improve
ductility in transverse bending. It increases the life of heat-conducting materials. It is also a
strong carbide former and produces a contracted austenite phase field [5,15].
1.2.20 LEAD
Lead (Pb) is sometimes added (in the range of 0.20.5%) to carbon and alloy steels through
mechanical dispersion during teeming to improve machinability.
1.2.21 TIN
Tin (Sn) in relatively small amounts is harmful to steels. It hasavery strong tendency to segregate
at grain boundaries and induces temper embrittlement in alloy steels. It has a detrimental effect
on the surface quality of continuous cast billets containing small amounts of Cu [24]. Small
amountsofSnandCualsodecrease thehotductilityof steels in theaustenite ferrite region [25].
1.2.22 ANTIMONY
Antimony (Sb) has a strong tendency to segregate during the freezing process, and has a
detrimental effect on the surface quality of continuous cast billets. It also has a very strong
tendency to segregate at grain boundaries and cause temper embrittlement in alloy steels.
1.2.23 CALCIUM
Calcium (Ca) is a strong deoxidizer; silicocalcium is used usually in steelmaking. The combin-
ation of Ca, Al, and Si forms low-melting oxides in steelmaking, and improves machinability.
1.3 CLASSIFICATION OF STEELS
Steels can be classified by different systems depending on [4,6,8]:
1. Compositions, such as carbon (or nonalloy), low-alloy, and alloy steels
2. Manufacturing methods, such as converter, electric furnace, or electroslag remelting
methods
3. Application or main characteristic, such as structural, tool, stainless steel, or heat-
resistant steels
4. Finishing methods, such as hot rolling, cold rolling, casting, or controlled rolling and
controlled cooling
5. Product shape, such as bar, plate, strip, tubing, or structural shape
6. Oxidation practice employed, such as rimmed, killed, semikilled, and capped steels
7. Microstructure, such as ferritic, pearlitic, martensitic, and austenitic (Figure 1.1)
8. Required strength level, as specified in the American Society for Testing and Materials
(ASTM) standards
9. Heat treatment, such as annealing, quenching and tempering, air cooling (normaliza-
tion), and thermomechanical processing
10. Quality descriptors and classifications, such as forging quality and commercial quality
Among the above classification systems, chemical composition is the most widely used basis
for designation and is given due emphasis in this chapter. Classification systems based on
oxidation practice, application, and quality descriptors are also briefly discussed.
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8 Steel Heat Treatment: Metallurgy and Technologies
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1.3.1 TYPES OF STEELS BASED ON DEOXIDATION PRACTICE
Steels, when cast into ingots, can be classified into four types according to the deoxidation
practice or, alternatively, by the amount of gas evolved during solidification. These four types
are called killed, semikilled, capped, and rimmed steels [6,8].
1.3.1.1 Killed Steels
Killed steel is a type of steel from which there is practically no evolution of gas during solidifi-
cation of the ingot after pouring, because of the complete deoxidation, and formation of pipe in
the upper central portion of the ingot, which is later cut off and discarded. All alloy steels, most
Classification bycommercial name
or application
Ferrous alloys
Steel
Plain carbonsteel
Low-carbonsteel
(0.5% C)
Low- and medium-alloy steel
10% alloyingelements
High-alloysteel
>10% alloyingelements
Corrosionresistant
Heatresistant
Wearresistant Duplex
structure
Austeniticferritic
Precipitationhardened
Austenitic
Bainitic
Martensitic
Pearlitic
Ferriticpearlitic
Classificationby structure
Alloys withouteutectic
(
-
low-alloy steels, andmanycarbon steels areusuallykilled.The continuous castingbillets are also
killed. The essential quality criterion is soundness [2628]. Killed steel is characterized by a
homogeneous structure and even distribution of chemical compositions and properties.
Killed steel is produced by the use of a deoxidizer such as Al and a ferroalloy of Mn or Si;
However, calcium silicide and other special deoxidizers are sometimes used.
1.3.1.2 Semikilled Steels
Gas evolution is not completely suppressed by deoxidizing additions in semikilled steel,
because it is partially deoxidized. There is a greater degree of gas evolution than in killed
steel, but less than in capped or rimmed steel. An ingot skin of considerable thickness is
formed before the beginning of gas evolution. A correctly deoxidized semikilled steel ingot
does not have a pipe but does have well-scattered large blow holes in the top-center half of the
ingot; however, the blow holes weld shut during rolling of the ingot. Semikilled steels
generally have a carbon content in the range of 0.150.30%. They find a wide range of uses
in structural shapes, skelp, and pipe applications. The main features of semikilled steels are
UJ variable degrees of uniformity in composition, which are intermediate between those of
killed and rimmed steels and less segregation than rimmed steel, and (2) a pronounced
tendency for positive chemical segregation at the top center of the ingot (Figure 1.2).
1.3.1.3 Rimmed Steels
Rimmed steel is characterized by a great degree of gas evolution during solidification in the
mold and a marked difference in chemical composition across the section and from the top to
the bottom of the ingot (Figure 1.2). These result in the formation of an outer ingot skin or
rim of relatively pure iron and an inner liquid (core) portion of the ingot with higher
concentrations of alloying and residual elements, especially C, N, S, and P, having lower
melting temperature. The higher purity zone at the surface is preserved during rolling [28].
Rimmed ingots are best suited for the manufacture of many products, such as plates, sheets,
wires, tubes, and shapes, where good surface or ductility is required [28].
The technology of producing rimmed steels limits the maximum content of C and Mn, and
the steel does not retain any significant amount of highly oxidizable elements such as Al, Si, or
Ti. Rimmed steels are cheaper than killed or semikilled steels for only a small addition of
deoxidizer is required and is formed without top scrap.
1 2 3 4 5 6 7 8
Killed Semikilled Capped Rimmed
FIGURE 1.2 Eight typical conditions of commercial steel ingots, cast in identical bottle-top molds, inrelation to the degree of suppression of gas evolution. The dotted line denotes the height to which the
steel originally was poured in each ingot mold. Based on the carbon, and more significantly, the oxygen
content of the steel, the ingot structures range from that of a completely killed ingot (No. 1) to that of a
violently rimmed ingot (No. 8). (From W.D. Landford and H.E. McGannon, Eds., The Making,
Shaping, and Treating of Steel, 10th ed., U.S. Steel, Pittsburgh, PA, 1985.)
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10 Steel Heat Treatment: Metallurgy and Technologies
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1.3.1.4 Capped Steels
Capped steel is a type of steel with characteristics similar to those of a rimmed steel but to a
degree intermediate between that of rimmed and semikilled steels. Less deoxidizer is used to
produce a capped ingot than to produce a semikilled ingot [29]. This induces a controlled
rimming action when the ingot is cast. The gas entrapped during solidification is excess of that
required to counteract normal shrinkage, resulting in a tendency for the steel to rise in the mold.
Capping is a variation of rimmed steel practice. The capping operation confines the time
of gas evolution and prevents the formation of an excessive number of gas voids within the
ingot. The capped ingot process is usually applied to steels with carbon contents greater than
0.15% that are used for sheet, strip, tin plate, skelp, wire, and bars.
Mechanically capped steel is poured into bottle-top molds using a heavy cast iron cap to
seal the top of the ingot and to stop the rimming action [29]. Chemically capped steel is cast in
open-top molds. The capping is accomplished by the addition of Al or ferrosilicon to the top
of the ingot, causing the steel at the top surface to solidify rapidly. The top portion of the
ingot is cropped and discarded.
1.3.2 QUALITY DESCRIPTORS AND CLASSIFICATIONS
Quality descriptors are names applied to various steel products to indicate that a particular
product possesses certain characteristics that make it especially well suited for specific applica-
tions or fabrication processes. The quality designations and descriptors for various carbon steel
products and alloy steel plates are listed in Table 1.1. Forging quality and cold extrusion quality
descriptors for carbon steels are self-explanatory. However, others are not explicit; for example,
merchant quality hot-rolled carbon steel bars are made for noncritical applications requiring
modest strength and mild bending or forming but not requiring forging or heat-treating oper-
ations. The quality classification for one steel commodity is not necessarily extended to subse-
quent productsmade from the same commodity; for example, standard quality cold-finished bars
are produced from special quality hot-rolled carbon steel bars. Alloy steel plate qualities are
described by structural, drawing, cold working, pressure vessel, and aircraft qualities [27].
The various physical and mechanical characteristics indicated by a quality descriptor result
from the combined effects of several factors such as (1) the degree of internal soundness, (2) the
relative uniformity of chemical composition, (3) the number, size, and distribution of non-
metallic inclusions, (4) the relative freedom from harmful surface imperfections, (5) extensive
testing during manufacture, (6) the size of the discard cropped from the ingot, and (7) hard-
enability requirements. Control of these factors during manufacture is essential to achieve mill
products with the desired characteristics. The degree of control over these and other related
factors is another segment of information conveyed by the quality descriptor.
Some, but not all, of the basic quality descriptors may be modified by one or more
additional requirements as may be appropriate, namely macroetch test, special discard,
restricted chemical composition, maximum incidental (residual) alloying elements, austenitic
grain size, and special hardenability. These limitations could be applied forging quality alloy
steel bars but not to merchant quality bars.
Understanding the various quality descriptors is difficult because most of the prerequisites
for qualifying steel for a specific descriptor are subjective. Only limitations on chemical
composition ranges, residual alloying elements, nonmetallic inclusion count, austenitic grain
size, and special hardenability are quantifiable. The subjective evaluation of the other attributes
depends on the experience and the skill of the individuals who make the evaluation. Although
the use of these subjective quality descriptors might appear impractical and imprecise, steel
products made to meet the requirements of a specific quality descriptor can be relied upon to
have those characteristics necessary for that product to be used in the suggested application or
fabrication operation [6].
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 11 17.8.2006 4:37pm
Steel Nomenclature 11
-
TABLE 1.1Quality Descriptionsa of Carbon and Alloy Steels
Carbon Steels Alloy Steels
Semifinished for forging Hot-rolled sheets Mill products Alloy steel plates
Forging quality
Special hardenability
Special internal
soundness
Nonmetallic inclusion
requirement
Special surface
Carbon steel structural
sections
Structural quality
Carbon steel plates
Regular quality
Structural quality
Cold-drawing quality
Cold-pressing quality
Cold-flanging quality
Forging quality
Pressure vessel quality
Hot-rolled carbon steel
bars
Merchant quality
Special quality
Special hardenability
Special internal
soundness
Nonmetallic inclusion
requirement
Special surface
Scrapless nut quality
Axle shaft quality
Cold extrusion quality
Cold-heading and cold-
forging quality
Cold-finished carbon steel
bars
Standard quality
Special hardenability
Special internal
soundness
Nonmetallic inclusion
requirement
Special surface
Cold-heading and cold-
forging quality
Cold extrusion quality
Commercial quality
Drawing quality
Drawing quality special
killed
Structural quality
Cold-rolled sheets
Commercial quality
Drawing quality
Drawing quality special
killed
Structural quality
Porcelain enameling sheets
Commercial quality
Drawing quality
Drawing quality special
killed
Long terne sheets
Commercial quality
Drawing quality
Drawing quality special
killed
Structural quality
Galvanized sheets
Commercial quality
Drawing quality
Drawing quality special
killed
Lock-forming quality
Electrolytic zinc coated
sheets
Commercial quality
Drawing quality
Drawing quality special
killed
Structural quality
Hot-rolled strip
Commercial quality
Drawing quality
Drawing quality special
killed
Structural quality
Cold-rolled strip
Specific quality
descriptions are not
Specific quality
descriptions are not
applicable to tin mill
products
Carbon steel wire
Industrial quality wire
Cold extrusion wires
Heading, forging, and
roll-threading wires
Mechanical spring wires
Upholstery spring
construction wires
Welding wire
Carbon steel flut wire
Stitching wire
Stapling wire
Carbon steel pipe
Structural tubing
Line pipe
Oil country tubular goods
Steel specialty tubular
products
Pressure tubing
Mechanical tubing
Aircraft tubing
Hot-rolled carbon steel
wire rods
Industrial quality
Rods for
manufacture of
wire intended for
electric welded chain
Rods for heading,
forging, and roll-
threading wire
Rods for lock washer
wire
Rods for scrapless nut
wire
Rods for upholstery
spring wire
Rods for welding wire
Drawing quality
Pressure vessel quality
Structural quality
Aircraft physical quality
Hot-rolled alloy steel bars
Regular quality
Aircraft quality or steel
subject to magnetic
particle inspection
Axle shaft quality
Bearing quality
Cold-heading quality
Special cold-heading
quality
Rifle barrel quality,
gun quality, shell or
A.P. shot quality
Alloy steel wire
Aircraft quality
Bearing quality
Special surface quality
Cold-finished alloy steel
bars
Regular quality
Aircraft quality or
steel subject to
magnetic particle
inspection
Axle shaft quality
Bearing shaft quality
Cold-heading quality
Special cold-heading
quality
Rifle barrel quality,
gun quality, shell or
A.P. shot quality
Line pipe
Oil country tubular goods
Steel specialty tubular
goods
Pressure tubing
Mechanical tubing
Stainless and heat-
resisting pipe,
pressure
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 12 17.8.2006 4:37pm
12 Steel Heat Treatment: Metallurgy and Technologies
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1.3.3 CLASSIFICATION OF STEEL BASED ON CHEMICAL COMPOSITION
1.3.3.1 Carbon and CarbonManganese Steels
In addition to carbon, plain carbon steels contain the following other elements: Mn up to
1.65%, S up to 0.05%, P up to 0.04%, Si up to 0.60%, and Cu up to 0.60%. The effects of each
of these elements in plain carbon steels have been summarized in Section 1.2.
Carbon steel can be classified according to various deoxidation processes (see Section 1.3.1).
Deoxidation practice and steelmaking process will have an effect on the characteristics and
properties of the steel (see Section 1.2). However, variations in C content have the greatest effect
on mechanical properties, with C additions leading to increased hardness and strength. As such,
carbon steels are generally grouped according to their C content. In general, carbon steels contain
up to 2% total alloying elements and can be subdivided into low-carbon, medium-carbon, high-
carbon, and ultrahigh-carbon (UHC) steels; each of these designations is discussed below.
As a group, carbon steels constitute the most frequently used steel. Table 1.2 lists various
grades of standard carbon and low-alloy steels with the Society of Automotive Engineers and
American Iron and Steel Institute (SAE-AISI) designations. Table 1.3 shows some represen-
tative standard carbon steel compositions with SAE-AISI and the corresponding Unified
Numbering System (UNS) designations [6,8,30].
Low-carbon steels contain up to 0.25% C. The largest category of this class is flat-rolled
products (sheet or strip), usually in the cold-rolled or subcritical annealed condition and
usually with final temper-rolling treatment. The carbon content for high formability and high
drawability steels is very low (
-
TA
BLE
1.2
SAE-
AIS
ID
esig
nat
ion
Syst
emfo
rC
arbon
and
Low
-Alloy
Stee
ls
Num
e ra l
sa n
d
Dig
its
Ty p
eof
S te e
la n
dN
om
ina l
Alloy
Conte
nt
(%)
Num
e ra l
sa n
d
Dig
its
Ty p
eof
S te e
la n
dN
om
ina l
All
oy
Conte
nt
(%)
Num
e ra l
sa n
dD
igit
s
Ty p
eof
S te e
la n
dN
om
ina l
Alloy
Conte
nt
(%)
Car b
on
s te e
lsN
icke l
c h
r om
ium
m
oly
bde n
um
s te e
lsC
hr o
miu
m(b
e ar ing)s t
e els
10xxa
. ... .
.. .
.Pla
inca
rbon
(Mn
1.0
0m
ax)
11xx
. ... .
.. .
.R
esulfurize
d
12xx
. ... .
.. .
.R
esulfurize
dand
rephosp
horize
d
15xx
. ... .
.. .
.Pla
inca
rbon
(max
Mn
range:
1.0
01.6
5)
Manganes
est
eels
13xx
. ... .
.. .
.M
n1.7
5
Nic
kel
stee
ls
23xx
.....
...
.N
i3.5
0
25xx
.....
...
.N
i5.0
0
Nic
kel
ch
rom
ium
stee
ls
31xx
.....
...
.N
i1.2
5;C
r0.6
5and
0.8
0
32xx
.....
...
.N
i1.7
5;C
r1.0
7
33xx
.....
...
.N
i3.5
0;C
r1.5
0and
1.5
7
34xx
.....
...
.N
i3.0
0;C
r0.7
7
Moly
bden
um
stee
ls
40xx
.....
...
.M
o0.2
0and
0.2
5
44xx
.....
...
.M
o0.4
0and
0.5
2
Chro
miu
mm
oly
bden
um
stee
ls
41xx
.....
...
.C
r0.5
0,0.8
0,and
0.9
5;M
o0.1
2,0.2
0,
0.2
5,and
0.3
0
43xx
. ... .
.. .
.N
i1.8
2;C
r0.5
0and
0.8
0;
Mo
0.2
5
43BV
xx
Ni1.8
2;C
r0.5
0;M
o0.1
2and
0.2
5;V
0.0
3m
in
47xx
. ... .
.. .
.N
i1.0
5;C
r0.4
5;M
o0.2
0and
0.3
5
81xx
. ... .
.. .
.N
i0.3
0;C
r0.4
0;M
o0.1
2
86xx
.....
...
.N
i0.5
5;C
r0.5
0;M
o0.2
0
87xx
.....
...
.N
i0.5
5;C
r0.5
0;M
o0.2
5
88xx
.....
...
.N
i0.5
5;C
r0.5
0;M
o0.3
5
93xx
.....
...
.N
i3.2
5;C
r1.2
0;M
o0.1
2
94xx
.....
...
.N
i0.4
5;C
r0.4
0;M
o0.1
2
97xx
.....
...
.N
i0.5
5;C
r0.2
0;M
o0.2
0
98xx
.....
...
.N
i1.0
0;C
r0.8
0;M
o0.2
5
Nic
kel
m
oly
bden
um
stee
ls
46xx
.....
...
.N
i0.8
5and
1.8
2;M
o0.2
0and
0.2
5
48xx
.....
...
.N
i3.5
0;M
o0.2
5
Chro
miu
mst
eels
50xx
.....
...
.C
r0.2
7,0.4
0,0.5
0,and
0.6
5
51xx
.....
...
.C
r0.8
0,0.8
7,0.9
2,0.9
5,1.0
0,and
1.0
5
50xxx. .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
.Cr
0.5
0
51xxx. .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
. Cr
1.0
2m
inC
1.0
0
52xxx. .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
.Cr
1.4
5
Chro
miu
mva
nadiu
mst
eels
61xx
. ... .
.. .
.. .
.. .
.. .
.. .
.. .
.. .
.C
r0.6
0,0.8
0,and
0.9
5;
V0.1
0and
0.1
5m
inT
ungst
ench
rom
ium
stee
l
72xx
.....
...
...
...
...
...
...
...
.W
1.7
5;C
r0.7
5
Silic
onm
anganes
est
eels
92xx
.....
...
...
...
...
...
...
...
.Si1.4
0and
2.0
0;M
n
0.6
5,0.8
2,and
0.8
5;
Cr
0and
0.6
5H
igh-s
tren
gth
low
-alloy
stee
ls
9xx
.....
...
...
...
...
...
...
...
.V
arious
SA
Egra
des
Boro
nst
eels
xxB
xx
.....
...
...
...
...
...
...
...
.Bden
ote
sboro
nst
eel
Lea
ded
stee
ls
xxL
xx
.....
...
...
...
...
...
...
...
.Lden
ote
sle
aded
stee
l
aT
he
xx
inth
ela
sttw
odig
its
ofth
ese
des
ignations
indic
ate
sth
atth
eca
rbon
conte
nt(in
hundre
dth
sofa
per
cent)
isto
be
inse
rted
.
Sourc
e:Fro
mC
ourt
esy
ofA
SM
Inte
rnational,
Mate
rials
Park
,O
H.W
ith
per
mission.
)
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 14 17.8.2006 4:37pm
14 Steel Heat Treatment: Metallurgy and Technologies
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TABLE 1.3Standard Carbon Steel Compositions with SAE-AISI and Corresponding UNS Designations
Plain Carbon Steel (Nonresulfurized, 1.0% Mn Max)a
UNS SAE-AISICast or Heat Chemical Ranges and Limits (%)a
Number Number C Mn P max S max
G10060 1006 0.08 max 0.45 max 0.040 0.050
G10080 1008 0.10 max 0.50 max 0.040 0.050
G10090 1009 0.15 max 0.60 max 0.040 0.050
G10100 1010 0.080.13 0.300.60 0.040 0.050
G10120 1012 0.100.15 0.300.60 0.040 0.050
G10150 1015 0.120.18 0.300.60 0.040 0.050
G10160 1016 0.120.18 0.600.90 0.040 0.050
G10170 1017 0.140.20 0.300.60 0.040 0.050
G10180 1018 0.140.20 0.600.90 0.040 0.050
G10190 1019 0.140.20 0.701.00 0.040 0.050
G10200 1020 0.170.23 0.300.60 0.040 0.050
G10210 1021 0.170.23 0.600.90 0.040 0.050
G10220 1022 0.170.23 0.701.00 0.040 0.050
G10230 1023 0.190.25 0.300.60 0.040 0.050
G10250 1025 0.220.28 0.300.60 0.040 0.050
G10260 1026 0.220.28 0.600.90 0.040 0.050
G10300 1030 0.270.34 0.600.90 0.040 0.050
G10330 1033 0.290.36 0.701.00 0.040 0.050
G10350 1035 0.310.38 0.600.90 0.040 0.050
G10370 1037 0.310.38 0.701.00 0.040 0.050
G10380 1038 0.340.42 0.600.90 0.040 0.050
G10390 1039 0.360.44 0.701.00 0.040 0.050
G10400 1040 0.360.44 0.600.90 0.040 0.050
G10420 1042 0.390.47 0.600.90 0.040 0.050
G10430 1043 0.390.47 0.701.00 0.040 0.050
G10450 1045 0.420.50 0.600.90 0.040 0.050
G10490 1049 0.450.53 0.600.90 0.040 0.050
G10500 1050 0.470.55 0.600.90 0.040 0.050
G10550 1055 0.520.60 0.600.90 0.040 0.050
G10600 1060 0.550.66 0.600.90 0.040 0.050
G10640 1064 0.590.70 0.500.80 0.040 0.050
G10650 1065 0.590.70 0.600.90 0.040 0.050
G10700 1070 0.650.76 0.600.90 0.040 0.050
G10740 1074 0.690.80 0.500.80 0.040 0.050
G10750 1075 0.690.80 0.400.70 0.040 0.050
G10780 1078 0.720.86 0.300.60 0.040 0.050
G10800 1080 0.740.88 0.600.90 0.040 0.050
G10840 1084 0.800.94 0.600.90 0.040 0.050
G10850 1085 0.800.94 0.701.00 0.040 0.050
G10860 1086 0.800.94 0.300.50 0.040 0.050
G10900 1090 0.840.98 0.600.90 0.040 0.050
G10950 1095 0.901.04 0.300.50 0.040 0.050
Continued
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 15 17.8.2006 4:37pm
Steel Nomenclature 15
-
TABLE 1.3 (Continued)Standard Carbon Steel Compositions with SAE-AISI and Corresponding UNS Designations
Free-Cutting (Resulfurized) Carbon Steel Compositionsa
UNS SAE-AISICast or Heat Chemical Ranges and Limits (%)
Number Number C Mn P max S
G11080 1108 0.080.13 0.500.80 0.040 0.080.13
G11100 1110 0.080.13 0.300.60 0.040 0.080.13
G11170 1117 0.140.20 1.001.30 0.040 0.080.13
G11180 1118 0.140.20 1.301.60 0.040 0.080.13
G11370 1137 0.320.39 1.351.65 0.040 0.080.13
G11390 1139 0.350.43 1.351.65 0.040 0.130.20
G11400 1140 0.370.44 0.701.00 0.040 0.080.13
G11410 1141 0.370.45 1.351.65 0.040 0.080.13
G11440 1144 0.400.48 1.351.65 0.040 0.240.33
G11460 1146 0.420.49 0.701.00 0.040 0.080.13
G11S10 1151 0.480.55 0.701.00 0.040 0.080.13
Standard Resulfurized and Rephosphorized Carbon Steelsa
UNS SAE-AISICast or Heat Chemical Ranges and Limits, %(a)
Number Number C max Mn P S Pb
Gl2110 1211 . . . . . . . . . 0.13 0.600.90 0.070.12 0.100.15
G12120 1212 . . . . . . . . . 0.13 0.701.00 0.070.12 0.160.23
G12130 1213 . . . . . . . . . 0.13 0.701.00 0.070.12 0.240.33
G12150 1215 . . . . . . . . . 0.09 0.751.05 0.040.09 0.260.35
G12144 12L14b . . . . . . . . . 0.15 0.851.15 0.040.09 0.260.35 0.150.35
Standard Nonresulfurized Carbon Steels (Over 1.0% Manganese)
UNS SAE-AISICast or Heat Chemical Ranges and Limits, %
Number Number C Mn P max S max
G15130 1513 . . . . . . . . . . . . . . . . . . 0.100.16 1.101.40 0.040 0.050
G15220 1522 . . . . . . . . . . . . . . . . . . 0.180.24 1.101.40 0.040 0.050
G15240 1524 . . . . . . . . . . . . . . . . . . 0.190.25 1.351.65 0.040 0.050
G15260 1526 . . . . . . . . . . . . . . . . . . 0.220.29 1.101.40 0.040 0.050
G15270 1527 . . . . . . . . . . . . . . . . . . 0.220.29 1.201.50 0.040 0.050
G15360 1536 . . . . . . . . . . . . . . . . . . 0.300.37 1.201.50 0.040 0.050
G15410 1541 . . . . . . . . . . . . . . . . . . 0.360.44 1.351.65 0.040 0.050
G15480 1548 . . . . . . . . . . . . . . . . . . 0.440.52 1.101.40 0.040 0.050
G15510 1551 . . . . . . . . . . . . . . . . . . 0.450.56 0.851.15 0.040 0.050
G15520 1552 . . . . . . . . . . . . . . . . . . 0.470.55 1.201.50 0.040 0.050
G15610 1561 . . . . . . . . . . . . . . . . . . 0.550.65 0.751.05 0.040 0.050
G15660 1566 . . . . . . . . . . . . . . . . . . 0.600.71 0.851.15 0.040 0.050
Applicable to semifinished products for forging, hot-rolled and cold-finished bars, wire rods, and seamless tubing.aIt is not common practice to produce the 12xx series of steels to specified limits for silicon because of its adverse effect
on machinability.bContains 0.150.35% lead; other steels listed here can be produced with similar amounts of lead.
Source: From Numbering System, Chemical Composition, 1993 SAE Handbook, Vol. 1, Materials Society of Automotive
Engineers, Warrendale, PA, pp. 1.011.189.
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 16 17.8.2006 4:37pm
16 Steel Heat Treatment: Metallurgy and Technologies
-
sections containing ~0.25% C, with up to 1.5% Mn and Al are used if improved toughness is
required. When used for stampings, forgings, seamless tubes, and boilerplate, Al addition should
be avoided. An important type of this category is the low-carbon free-cutting steels containing up
to 0.15% C and up to 1.2% Mn, a minimum of Si and up to 0.35% S with or without 0.30% Pb.
These steels are suited for automotive mass production manufacturing methods [4].
Medium-carbon steels containing 0.300.55% C and 0.601.65% Mn are used where
higher mechanical properties are desired. They are usually hardened and strengthened by
heat treatment or by cold work. Low-carbon and manganese steels in this group find wide
applications for certain types of cold-formed parts that need annealing, normalizing, or
quenching and tempering treatment before use. The higher carbon grades are often cold
drawn to specific mechanical properties for use without heat treatment for some applications.
All of these steels can be used for forgings, and their selection is dependent on the section
size and the mechanical properties needed after heat treatment [8]. These grades, generally
produced as killed steels, are used for a wide range of applications that include automobile
parts for body, engines, suspensions, steering, engine torque converter, and transmission [31].
Some Pb or S additions make them free-cutting grades, whereas Al addition produces grain
refinement and improved toughness. In general, steels containing 0.400.60% C are used as
rails, railway wheels, tires, and axles.
High-carbon steels containing 0.551.00% C and 0.300.90% Mn have more restricted
applications than the medium-carbon steels because of higher production cost and poor
formability (or ductility) and weldability. High-carbon steels find applications in the spring
industry (as light and thicker plat springs, laminated springs, and heavier coiled springs), farm
implement industry (as plow beams, plowshares, scraper blades, discs, mowers, knives, and
harrow teeth), and high-strength wires where improved wear characteristics and higher
strength than those attainable with lower carbon grades are needed.
UHC steels are experimental plain carbon steels with 1.02.1% C (1532 vol% cementite)
[3234]. Optimum superplastic elongation has been found at about 1.6% C content [9]. These
steels have the capability of emerging as important technological materials because they
exhibit superplasticity. The superplastic behavior of these materials is attributed to the
structure consisting of uniform distribution of very fine, spherical, discontinuous particles
(0:1---1:5mm diameter) in a very fine-grained ferrite matrix (0:5---2:0mm diameter) that can bereadily achieved by any of the four thermomechanical treatment routes described elsewhere [4].
1.3.3.2 Low-Alloy Steels
Alloy steels may be defined as those steels that owe their improved properties to the presence
of one or more special elements or to the presence of large proportions of elements such as
Mn and Si than are ordinarily present in carbon steels [26]. Alloy steels contain Mn, Si, or Cu
in quantities greater than the maximum limits (e.g., 1.65% Mn, 0.60% Si, and 0.60% Cu) of
carbon steels, or they contain special ranges or minimums of one or more alloying elements.
However, in some countries Mn, Si, or Cu as an alloy element in low-alloy and alloy steels is
only greater than 1.00% Mn, 0.50% Si, or 0.10% Cu [7].
The alloying elements increase the mechanical and fabrication properties. Broadly, alloy
steels can be divided into (1) low-alloy steels containing less than 5 wt% total noncarbon alloy
addition, (2) medium-alloy steels containing 510 wt% total noncarbon alloy addition, and (3)
high-alloy steels with more than 10wt% total noncarbon alloy addition. Table 1.4 lists some
low-alloy steel compositions with SAE-AISI and corresponding UNS designations.
Low-alloy steels constitute a group of steels that exhibit superior mechanical properties
compared to plain carbon steels as the result of addition of such alloying elements as Ni, Cr,
and Mo. For many low-alloy steels, the main function of the alloying elements is to increase
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 17 17.8.2006 4:37pm
Steel Nomenclature 17
-
TA
BLE
1.4
Low
-Alloy
Stee
lC
om
posi
tions
Applica
ble
toB
ille
ts,
Blo
om
s,Sl
abs,
and
Hot-
Rolled
and
Cold
-Fin
ished
Bar
s(S
ligh
tly
Wid
erR
ange
s
of
Com
pos i
tions
Apply
toPla
tes )
UN
S
Num
be r
S AE
Num
be r
Cor r
e spondin
g
AIS
IN
um
be r
L adle
Che m
ica l
Com
pos i
tion
L im
its
(%)a
CM
nP
SSi
Ni
Cr
Mo
V
G13300
1330
1330
0.2
80.3
31.6
01.9
00.0
35
0.0
40
0.1
50.3
5
G13350
1335
1335
0.3
30.3
81.6
01.9
00.0
35
0.0
40
0.1
50.3
5
G13400
1340
1340
0.3
80.4
31.6
01.9
00.0
35
0.0
40
0.1
50.3
5
G13450
1345
1345
0.4
30.4
81.6
01.9
00.0
35
0.0
40
0.1
50.3
5
G40230
4023
4023
0.2
00.2
50.7
00.9
00.0
35
0.0
40
0.1
50.3
5
G40240
4024
4024
0.2
00.2
50.7
00.9
00.0
35
0.0
350.0
50
0.1
50.3
5
0.2
00.3
0
G40270
4027
4027
0.2
50.3
00.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
0
G40280
4028
4028
0.2
50.3
00.7
00.9
00.0
35
0.0
350.0
50
0.1
50.3
5
0.2
00.3
0
G40320
4032
0.3
00.3
50.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
0
G40370
4037
4037
0.3
50.4
00.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
0
G40420
4042
0.4
00.4
50.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
0
G40470
4047
4047
0.4
50.5
00.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
0
G41180
4118
4118
0.1
80.2
30.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.4
00.6
00.0
80.1
5
G41300
4130
4130
0.2
80.3
30.4
00.6
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41350
4135
0.3
30.3
80.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41370
4137
4137
0.3
50.4
00.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41400
4140
4140
0.3
80.4
30.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41420
4142
4142
0.4
00.4
50.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41450
4145
4145
0.4
10.4
80.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41470
4147
4147
0.4
50.5
00.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41500
4150
4150
0.4
80.5
30.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
00.1
50.2
5
G41610
4161
4161
0.5
60.6
40.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
00.2
50.3
5
G43200
4320
4320
0.1
70.2
20.4
50.6
50.0
35
0.0
40
0.1
50.3
51.6
52.0
00.4
00.6
00.2
00.3
0
G43400
4340
4340
0.3
80.4
30.6
00.8
00.0
35
0.0
40
0.1
50.3
51.6
52.0
00.7
00.9
00.2
00.3
0
G43406
E4340
bE
4340
0.3
80.4
30.6
50.8
50.0
25
0.0
25
0.1
50.3
51.6
52.0
00.7
00.9
00.2
00.3
0
G44220
4422
0.2
00.2
50.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.3
50.4
5
G44270
4427
0.2
40.2
90.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.3
50.4
5
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 18 17.8.2006 4:37pm
18 Steel Heat Treatment: Metallurgy and Technologies
-
G46150
4615
4615
0.1
30.1
80.4
50.6
50.0
35
0.0
40
0.1
50.2
51.6
52.0
0
0.2
00.3
0
G46170
4617
0.1
50.2
00.4
50.6
50.0
35
0.0
40
0.1
50.3
51.6
52.0
0
0.2
00.3
0
G46200
4620
4620
0.1
70.2
20.4
50.6
50.0
35
0.0
40
0.1
50.3
51.6
52.0
0
0.2
00.3
0
G46260
4626
4626
0.2
40.2
90.4
50.6
50.0
35
0.0
40
max
0.1
50.3
50.7
01.0
0
0.1
50.2
5
G47180
4718
4718
0.1
60.2
10.7
00.9
0
0.9
01.2
00.3
50.5
50.3
00.4
0
G47200
4720
4720
0.1
70.2
20.5
00.7
00.0
35
0.0
40
0.1
50.3
50.9
01.2
00.3
50.5
50.1
50.2
5
G48150
4815
4815
0.1
30.1
80.4
00.6
00.0
35
0.0
40
0.1
50.3
53.2
53.7
5
0.2
00.3
0
G48170
4817
4817
0.1
50.2
00.4
00.6
00.0
35
0.0
40
0.1
50.3
53.2
53.7
5
0.2
00.3
0
G48200
4820
4820
0.1
80.2
30.5
00.7
00.0
35
0.0
40
0.1
50.3
53.2
33.7
5
0.2
00.3
0
G50401
50B
40c
0.3
80.4
30.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.4
00.6
0
G50441
50B
44c
50B44
0.4
30.4
80.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.4
00.6
0
G50460
5O
46
0.4
30.4
80.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
5
G50461
50B
46c
50B46
0.4
40.4
90.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.2
00.3
5
G50501
50B
50c
50B50
0.4
80.5
30.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.4
00.6
0
G50600
5060
0.5
60.6
40.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.4
00.6
0
G50601
50B
60c
50B60
0.5
60.6
40.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.4
00.6
0
G51150
5115
0.1
30.1
80.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G51170
5117
5117
0.1
50.2
00.7
01.9
00.0
40
0.0
40
0.1
50.3
5
0.7
00.9
0
G51200
5120
5120
0.1
70.2
20.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G51300
5130
5130
0.2
80.3
30.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
0
G51320
5132
5132
0.3
00.3
50.6
00.8
00.0
35
0.0
40
0.1
50.3
5
0.7
51.0
0
G51350
5135
5135
0.3
30.3
80.6
00.8
00.0
35
0.0
40
0.1
53.3
5
0.8
01.0
5
G51400
5140
5140
0.3
80.4
30.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G51470
5147
5147
0.4
60.5
10.7
00.9
50.0
35
0.0
40
0.1
50.3
5
0.8
51.1
5
G51500
5150
5150
0.4
80.5
30.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G51550
5155
5155
0.5
10.5
90.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G51600
5160
5160
0.5
60.6
40.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G51601
51B
60c
51B60
0.5
60.6
40.7
51.0
00.0
35
0.0
40
0.1
50.3
5
0.7
00.9
0
G50986
50100b
0.9
81.1
00.2
50.4
50.0
25
0.0
25
0.1
50.3
5
0.4
00.6
0
G51986
51100b
E51100
0.9
81.1
00.2
50.4
50.0
25
0.0
25
0.1
50.3
5
0.9
01.1
5
G52986
52100b
E52100
0.9
81.1
00.2
50.4
50.0
25
0.0
25
0.1
50.3
5
1.3
01.6
0
Continued
Totten / Steel Heat Treatment: Metallurgy and Technologies DK9384_C001 Final Proof page 19 17.8.2006 4:37pm
Steel Nomenclature 19
-
TA
BLE
1.4
(Conti
nued
)Lo
w-A
lloy
Stee
lC
om
posi
tio
ns
Applica
ble
toB
ille
ts,
Blo
om
s,Sl
abs,
and
Hot-
Rolled
and
Cold
-Fin
ished
Bar
s(S
ligh
tly
Wid
erR
ange
s
of
Com
posi
tio
ns
Apply
toPla
tes)
UN
S
Num
ber
SAE
Num
ber
Corr
espondin
g
AIS
IN
um
ber
Ladle
Chem
ical
Com
posi
tion
Lim
its
(%)a
CM
nP
SSi
Ni
Cr
Mo
V
G61180
6118
6118
0.1
60.2
10.5
00.7
00.0
35
0.0
40
0.1
50.3
5
0.5
00.7
0
0.1
00.1
5
G61500
6150
6150
0.4
80.5
30.7
00.9
00.0
35
0.0
40
0.1
50.3
5
0.8
01.1
0
0.1
5m
in
G81150
8115
8115
0.1
30.1
80.7
00.9
00.0
35
0.0
40
0.1
50.3
50.2
00.4
00.3
00.5
00.0
80.1
5
G81451
81B
45c
81B
45
0.4
30.4
80.7
51.0
00.0
35
0.0
40
0.1
50.3
50.2
00.4
00.3
50.5
50.0
80.1
5
G86150
8615
8615
0.1
30.1
80.7
00.9
00.0
35
0.0
40
0.1
50.3
50.4
00.7
00.4
00.6
00.1
50.2
5
G86170
8617
8617
0.1
50.2
00.7
00.9
00.0
35
0.0
40
0.1
50.3
50.4
00.7
00.4
00.6
00.1
50.2
5
G86200
8620
8620
0.1
80.2
30.7
00.9
00.0
35
0.0
40
0.1
50.3
50.4
00.7
00.4
00.6
00.1
50.2
5
G86220
8622
8622
0.2
00.2
50.7
00.9
00.0
35
0.0
40
0.1
50.3
50.4
00.7
00.4
00.6
00.1
50.2
5
G86250
8625
8625
0.2
30.2
80.7
00.9
00.0
35
0.0
40
0.1
50.3
50.4
00.7
00.4
00.6
00.1
50.2