Volume 01 - Properties and Selection Irons, Steels, and High-Performance Alloys Part 1 docx

ASM INTERNATIONAL The Materials Information Company ® Volume Publication Information and Contributors Properties and Selection: Irons, Steels, and High-Performance Alloys was published in 1990 as Volume of the 10th Edition Metals Handbook With the second printing (1993), the series title was changed to ASM Handbook The Volume was prepared under the direction of the ASM International Handbook Committee Authors and Reviewers • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • LAMET UFRGS G Aggen Allegheny Ludlum Steel Division Allegheny Ludlum Corporation Frank W Akstens Industrial Fasteners Institute C Michael Allen Adjelian Allen Rubeli Ltd H.S Avery Consultant P Babu Caterpillar, Inc Alan M Bayer Teledyne Vasco Felix Bello The WEFA Group S.P Bhat Inland Steel Company M Blair Steel Founders' Society of America Bruce Boardman Deere and Company Technical Center Kurt W Boehm Nucor Steel Francis W Boulger Battelle-Columbus Laboratories (retired) Greg K Bouse Howmet Corporation John L Bowles North American Wire Products Corporation J.D Boyd Metallurgical Engineering Department Queen's University B.L Bramfitt Bethlehem Steel Corporation Richard W Bratt Consultant W.D Brentnall Solar Turbines C.R Brinkman Oak Ridge National Laboratory Edward J Bueche USS/Kobe Steel Company Harold Burrier, Jr The Timken Company Anthony Cammarata Mineral Commodities Division U.S Bureau of Mines A.P Cantwell LTV Steel Company M Carlucci Lorlea Steels Harry Charalambu Carr & Donald Associates Joseph B Conway Mar-Test Inc W Couts Wyman-Gordon Company Wil Danesi Garrett Processing Division Allied-Signal Aerospace Company John W Davis McDonnell Douglas R.J Dawson Deloro Stellite, Inc Terry A DeBold Carpenter Technology Corporation James Dimitrious Pfauter-Maag Cutting Tools Douglas V Doanne Consulting Metallurgist Mehmet Doner Allison Gas Turbine Division Henry Dormitzer Wyman-Gordon Company Allan B Dove Consultant (deceased) Don P.J Duchesne Adjelian Allen Rubeli Ltd Gary L Erickson Cannon-Muskegon Corporation Walter Facer American Spring Wire Company Brownell N Ferry LTV Steel Company F.B Fletcher Lukens Steel Company E.M Foley Deloro Stellite, Inc • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • R.D Forrest Division Fonderie Pechinery Electrometallurgie James Fox Charter Rolling Division Charter Manufacturing Company, Inc Edwin F Frederick Bar, Rod and Wire Division Bethlehem Steel Corporation James Gialamas USS/Kobe Steel Company Jeffery C Gibeling University of California at Davis Wayne Gismondi Union Drawn Steel Co., Ltd R.J Glodowski Armco, Inc Loren Godfrey Associated Spring Barnes Group, Inc Alan T Gorton Atlantic Steel Company W.G Granzow Research & Technology Armco, Inc David Gray Teledyne CAE Malcolm Gray Microalloying International, Inc Richard B Gundlach Climax Research Services I Gupta Inland Steel Company R.I.L Guthrie McGill Metals Processing Center McGill University P.C Hagopian Stelco Fastener and Forging Company J.M Hambright Inland Bar and Structural Division Inland Steel Company K Harris Cannon-Muskegon Corporation Hans J Heine Foundry Management & Technology W.E Heitmann Inland Steel Company T.A HeussLTV Steel Bar Division LTV Steel Company Thomas Hill Speedsteel of New Jersey, Inc M Hoetzl Surface Combustion, Inc Peter B Hopper Milford Products Corporation J.P Hrusovsky The Timken Company David Hudok Weirton Steel Corporation S Ibarra Amoco Corporation J.E Indacochea Department of Civil Engineering, Mechanics, and Metallurgy University of Illinois at Chicago Asjad Jalil The Morgan Construction Company William J Jarae Georgetown Steel Corporation Lyle R Jenkins Ductile Iron Society J.J Jonas McGill Metals Processing Center McGill University Robert S Kaplan U.S Bureau of Mines Donald M Keane LaSalle Steel Company William S Kirk U.S Bureau of Mines S.A Kish LTV Steel Company R.L Klueh Metals and Ceramics Division Oak Ridge National Laboratory G.J.W Kor The Timken Company Charles Kortovich PCC Airfoils George Krauss Advanced Steel Processing and Products Research Center Colorado School of Mines Eugene R Kuch Gardner Denver Division J.A Laverick The Timken Company M.J Leap The Timken Company P.W Lee The Timken Company B.F Leighton Canadian Drawn Steel Company R.W Leonard USX Corporation R.G Lessard Stelpipe Stelco, Inc S Liu Center for Welding and Joining Research Colorado School of Mines Carl R Loper, Jr Materials Science & Engineering Department University of WisconsinMadison Donald G Lordo Townsend Engineered Products R.A Lula Consultant • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • W.C Mack Babcock & Wilcox Division McDermott Company T.P Madvad USS/Kobe Steel Company J.K Mahaney, Jr LTV Steel Company C.W Marshall Battelle Memorial Institute G.T Matthews The Timken Company Gernant E Maurer Special Metals Corporation Joseph McAuliffe Lake Erie Screw Corporation Thomas J McCaffrey Carpenter Steel Division Carpenter Technology Corporation J McClain Danville Division Wyman-Gordon Company T.K McCluhan Elkem Metals Company D.B McCutcheon Steltech Technical Services Ltd Hal L Miller Nelson Wire Company K.L Miller The Timken Company Frank Minden Lone Star Steel Michael Mitchell Rockwell International R.W Monroe Steel Founders' Society of America Timothy E Moss Inland Bar and Structural Division Inland Steel Company Brian Murkey R.B & W Corporation T.E Murphy Inland Bar and Structural Division Inland Steel Company Janet Nash American Iron and Steel Institute Drew V Nelson Mechanical Engineering Department Stanford University G.B Olson Northwestern University George H Osteen Chaparral Steel J Otter Saginaw Division General Motors Corporation D.E Overby Stelco Technical Services Ltd John F Papp U.S Bureau of Mines Y.J Park Amax Research Company D.F Paulonis United Technologies Leander F Pease III Powder-Tech Associates, Inc Thoni V Philip TVP Inc Thomas A PhillipsDepartment of the Interior U.S Bureau of Mines K.E Pinnow Crucible Research Center Crucible Materials Corporation Arnold Plant Samuel G Keywell Company Christopher Plummer The WEFA Group J.A Pojeta LTV Steel Company R Randall Rariton River Steel P Repas U.S.S Technical Center USX Corporation M.K Repp The Timken Company Richard Rice Battelle Memorial Institute William L Roberts Consultant G.J Roe Bethlehem Steel Corporation Kurt Rohrbach Carpenter Technology Corporation A.R Rosenfield Battelle Memorial Institute James A Rossow Wyman-Gordon Company C.P Royer Exxon Production Research Company Mamdouh M Salama Conoco Inc Norman L Samways Association of Iron and Steel Engineers Gregory D Sander Ring Screw Works J.A Schmidt Joseph T Ryerson and Sons, Inc Michael Schmidt Carpenter Technology Corporation W Schuld Seneca Wire & Manufacturing Company R.E Schwer Cannon-Muskegon Corporation Kay M Shupe Bliss & Laughlin Steel Company V.K Sikka Oak Ridge National Laboratory • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Steve Slavonic Teledyne Columbia-Summerill Dale L Smith Argonne National Laboratory Richard B Smith Western Steel Division Stanadyne, Inc Dennis Smyth The Algoma Steel Corporation Ltd G.R Speich Department of Metallurgical Engineering Illinois Institute of Technology Thomas Spry Commonwealth Edition W Stasko Crucible Materials Corporation Crucible Research Center Doru M Stefanescu The University of Alabama Joseph R Stephens Lewis Research Center National Aeronautics and Space Administration P.A Stine General Electric Company N.S Stoloff Rensselaer Polytechnic Institute John R Stubbles LTV Steel Company D.K Subramanyam Ergenics, Inc A.E Swansiger ABC Rail Corporation R.W Swindeman Oak Ridge National Laboratory N Tepovich Connecticut Steel Millicent H Thomas LTV Steel Company Geoff Tither Niobium Products Company, Inc George F Vander Voort Carpenter Technology Corporation Elgin Van Meter Empire-Detroit Steel Division Cyclops Corporation Krishna M Vedula Materials Science & Engineering Department Case Western Reserve University G.M Waid The Timken Company Charles F Walton Consultant Lee R Walton Latrobe Steel Company Yung-Shih Wang Exxon Production Research Company S.D Wasko Allegheny Ludlum Steel Division Allegheny Ludlum Corporation J.R Weeks Brookhaven National Laboratory Charles V White GMI Engineering and Management Institute Alexander D Wilson Lukens Steel Company Peter H Wright Chaparral Steel Company B Yalamanchili North Star Steel Texas Company Z Zimerman Bethlehem Steel Corporation Foreword For nearly 70 years the Metals Handbook has been one of the most widely read and respected sources of information on the subject of metals Launched in 1923 as a single volume, it has remained a durable reference work, with each succeeding edition demonstrating a continuing upward trend in growth, in subject coverage, and in reader acceptance As we enter the final decade of the 20th century, the ever-quickening pace of modern life has forced an increasing demand for timely and accurate technical information Such a demand was the impetus for this, the 10th Edition of Metals Handbook Since the publication of Volume of the 9th Edition in 1978, there have been significant technological advances in the field of metallurgy The goal of the present volume is to document these advances as they pertain to the properties and selection of cast irons, steels, and superalloys A companion volume on properties and selection of nonferrous alloys, special-purpose materials, and pure metals will be published this autumn Projected volumes in the 10th Edition will present expanded coverage on processing and fabrication of metals; testing, inspection, and failure analysis; microstructural analysis and materials characterization; and corrosion and wear phenomena (the latter a subject area new to the Handbook series) During the 12 years it took to complete the 17 volumes of the 9th Edition, the high standards for technical reliability and comprehensiveness for which Metals Handbook is internationally known were retained Through the collective efforts of the ASM Handbook Committee, the editorial staff of the Handbook, and nearly 200 contributors from industry, research organizations, government establishments, and educational institutions, Volume of the 10th Edition continues this legacy of excellence • • Klaus M Zwilsky President ASM INTERNATIONAL Edward L Langer Managing Director ASM INTERNATIONAL Preface During the past decade, tremendous advances have taken place in the field of materials science Rapid technological growth and development of composite materials, plastics, and ceramics combined with continued improvements in ferrous and nonferrous metals have made materials selection one of the most challenging endeavors for engineers Yet the process of selection of materials has also evolved No longer is a mere recitation of specifications, compositions, and properties adequate when dealing with this complex operation Instead, information is needed that explains the correlation among the processing, structures, and properties of materials as well as their areas of use It is the aim of this volume the first in the new 10th Edition series of Metals Handbook to present such data Like the technology it documents, the Metals Handbook is also evolving To be truly effective and valid as a reference work, each Edition of the Handbook must have its own identity To merely repeat information, or to simply make superficial cosmetic changes, would be self-defeating As such, utmost care and thought were brought to the task of planning the 10th Edition by both the ASM Handbook Committee and the Editorial Staff To ensure that the 10th Edition continued the tradition of quality associated with the Handbook, it was agreed that it was necessary to: • • • • • Determine which subjects (articles) not included in previous Handbooks needed to be added to the 10th Edition Determine which previously published articles needed only to be revised and/or expanded Determine which previously published articles needed to be completely rewritten Determine which areas needed to be de-emphasized Identify and eliminate obsolete data The next step was to determine how the subject of properties selection should be addressed in the 10th Edition Considering the information explosion that has taken place during the past 30 years, the single-volume approach used for Volume of the 8th Edition (published in 1961) was not considered feasible For the 9th Edition, three separate volumes on properties and selection were published from 1978 to 1980 This approach, however, was considered somewhat fragmented, particularly in regard to steels: carbon and low-alloy steels were covered in Volume 1, whereas tools steels, austenitic manganese steels, and stainless steels were described in Volume After considering the various options, it was decided that the most logical and user-friendly approach would be to publish two comprehensive volumes on properties and selection In the present volume, emphasis has been placed on cast irons, carbon and low-alloy steels, and highperformance alloys such as stainless steels and superalloys A companion volume on properties and selection of nonferrous alloys and special-purpose materials will follow (see Table for an abbreviated table of contents) Table Abbreviated table of contents for Volume 2, 10th Edition, Metals Handbook Specific Metals and Alloys Wrought Aluminum and Aluminum Alloys Cast Aluminum Alloys Aluminum-Lithium Alloys Aluminum P/M Alloys Wrought Copper and Copper Alloys Cast Copper Alloys Copper P/M Products Nickel and Nickel Alloys Beryllium-Copper and Beryllium-Nickel Alloys Cobalt and Cobalt Alloys Magnesium and Magnesium Alloys Tin and Tin Alloys Zinc and Zinc Alloys Lead and Lead Alloys Refractory Metals and Alloys Wrought Titanium and Titanium Alloys Cast Titanium Alloys Titanium P/M Alloys Zirconium and Hafnium Uranium and Uranium Alloys Beryllium Precious Metals Rare Earth Metals Germanium and Germanium Compounds Gallium and Gallium Compounds Indium and Bismuth Special-Purpose Materials Soft Magnetic Materials Permanent Magnet Materials Metallic Glasses Superconducting Materials Electrical Resistance Alloys Electric Contact Materials Thermocouple Materials Low Expansion Alloys Shape-Memory Alloys Materials For Sliding Bearings Metal-Matrix Composite Materials Ordered Intermetallics Cemented Carbides Cermets Superabrasives and Ultrahard Tool Materials Structural Ceramics Pure Metals Preparation and Characterization of Pure Metals Properties of Pure Metals Special Engineering Topics Recycling of Nonferrous Alloys Toxicity of Metals Principal Sections Volume has been organized into seven major sections: • • • • • • • Cast Irons Carbon and Low-Alloy Steels Hardenability of Carbon and Low-Alloy Steels Fabrication Characteristics of Carbon and Low-Alloy Steels Service Characteristics of Carbon and Low-Alloy Steels Specialty Steels and Heat-Resistant Alloys Special Engineering Topics Of the 53 articles contained in these sections, 14 are new, 10 were completely rewritten, and the remaining articles have been substantially revised A review of the content of the major sections is given below; highlighted are differences between the present volume and its 9th Edition predecessor Table summarizes the content of the principal sections Table Summary of contents for Volume 1, 10th Edition, Metals Handbook Section title Number of articles Pages Figures(a) Tables(b) References Cast Irons 104 155 81 108 Carbon and Low-Allow Steels 21 344 298 266 230 Hardenability of Carbon and Low-Alloy Steels 122 210 178 28 Fabrication Characteristics of Carbon and Low-Alloy Steels 44 56 10 85 Service Characteristics of Carbon and Low-Alloy Steels 140 219 22 567 Specialty Steels and Heat-Resistant Alloys 11 252 249 163 358 Special Engineering Topics 27 29 11 50 53 1033 1216 731 1426 Totals (a) Total number of figure captions; some figures may include more than one illustration (b) Does not include unnumbered in-text tables or tables that are part of figures Cast irons are described in six articles The introductory article on "Classification and Basic Metallurgy of Cast Irons" was completely rewritten for the 10th Edition The article on "Compacted Graphite Iron" is new to the Handbook Both of these contributions were authored by D.M Stefanescu (The University of Alabama), who served as Chairman of Volume 15, Casting, of the 9th Edition The remaining four articles contain new information on materials (for example, austempered ductile iron) and testing (for example, dynamic tear testing) Carbon and Low-Alloy Steels Key additions to this section include articles that explain the relationships among processing (both melt and rolling processes), microstructures, and properties of steels Of particular note is the article by G Krauss (Colorado School of Mines) on pages 126 to 139 and the various articles on high-strength low-alloy steels Other highlights include an extensive tabular compilation that cross-references SAE-AISI steels to their international counterparts (see the article "Classification and Designation of Steels") and an article on "Bearing Steels" that compares both case-hardened and through-hardened bearing materials Hardenability of Carbon and Low-Alloy Steels Following articles that introduce H-steels and describe hardenability concepts, including test procedures to determine the hardening response of steels, a comprehensive collection of hardenability curves is presented Both English and metric hardenability curves are provided for some 86 steels Fabrication Characteristics Sheet formability, forgeability, machinability, and weldability are described next The article on bulk formability, which emphasizes recent studies on HSLA forging steels, is new to the Handbook series The material on weldability was completely rewritten and occupies nearly four times the space allotted in the 9th Edition Service Characteristics The influence of various in-service environments on the properties of steels is one of the most widely studied subjects in metallurgy Among the topics described in this section are elevated-temperature creep properties, low-temperature fracture toughness, fatigue properties, and impact toughness A new article also describes the deleterious effect of neutron irradiation on alloy and stainless steels Of critical importance to this section, however, is the definitive treatise on "Embrittlement of Steels" written by G.F Vander Voort (Carpenter Technology Corporation) Featuring more than 75 graphs and 372 references, this 48-page article explores the causes and effects of both thermal and environmental degradation on a wide variety of steels Compared with the 9th Edition on the same subject, this represents a nearly tenfold increase in coverage Specialty Steels and Heat-Resistant Alloys Eleven articles on wrought, cast, and powder metallurgy materials for specialty and/or high-performance applications make up this section Alloy development and selection criteria as related to corrosion-resistant and heat-resistant steels and superalloys are well documented More than 100 pages are devoted to stainless steels, while three new articles have been written on superalloys including one on newly developed directionally solidified and single-crystal nickel-base alloys used for aerospace engine applications Special Engineering Topics The final section examines two subjects that are becoming increasingly important to the engineering community: (1) the availability and supply of strategic materials, such as chromium and cobalt, used in High-speed steel tools Cemented carbide tools mm in mm in Face mill 0.15-0.30 0.006-0.012 0.20-0.40 0.008-0.015 Plain mill 0.13-0.23 0.005-0.009 0.15-0.30 0.006-0.012 End mill 0.08-0.20 0.003-0.008 0.08-0.25 0.003-0.010 Circular saw 0.05-0.10 0.002-0.004 0.02-0.10 0.001-0.004 Note: For milling speeds, see Table 14 Experience has shown that when converting from malleable iron or pearlitic malleable iron castings to ductile iron, surface speeds should be increased by about 20% This allows the chip to roll faster and break easier, improving tool life and thereby providing an increase in productivity The higher elongation of ductile iron causes the chips to roll and produce more abrasion on the tool This added abrasion is reduced if the chip breaks instead of rolling Also, as-cast ductile iron does not have the surface decarburized layer normally found in malleable irons that decreases tool life Work hardening is produced when machining ductile iron, making it important to avoid light cuts Coolants improve high-speed tool life, but are not as effective for carbide tool life until high-surface speeds are used A comparison can be made between the machinability of ASTM class 40 gray iron and that of ASTM grade 6040-18 ductile iron The gray iron has a tensile strength of about 275 MPa (40 ksi) and a hardness of 190 to 220 HBN The ductile irons have a yield strength of about 275 MPa (40 ksi) and a hardness of about 187 HBN The higher silicon content of ductile iron compared to malleable iron or gray cast iron causes the ferrite to be harder The recommended cutting speed for rough turning using a single-point high speed steel tool at a feed of about 0.38 mm/rev (0.015 in./rev) is 20 m/min (70 sfm) for ASTM class 40 gray iron and 43 m/min (140 sfm) for ASTM grade 60-40-18 ductile iron For a similar rough turning operation, cast mild steel with a tensile strength of about 415 to 485 MPa (60 to 70 ksi) requires a cutting speed of 33 m/min (110 sfm) Replacing the high speed steel tool with one made of sintered carbides allows increases in cutting speed for all three materials, but does not change the ratios of cutting speeds among the three materials For ductile iron, the cutting speed, using carbide tools dry, increases to about 82 m/min (270 sfm) Example 1: Comparison of the Machinability of Ferritic Ductile Iron With That of Selected Grades of Gray Cast Iron For this test program, test castings representing a range of cooling conditions were produced (see Fig 33) The five sections were then cut apart and centered, and the surfaces were turned off to depths of about 1.6 to 3.2 mm ( 16 to in.) The resulting diameters were 95, 70, 60, and 45 mm (3.75, 2.75, 2.37, and 1.75 in.) Test turning was done by making successive 0.508 mm (0.200 in.) cuts at a cutting speed of 76 m/min (250 sfm) Three cuts were made and timed for each test section The rate of metal removal was calculated for each size, and the data are shown in Fig 33(a) Fig 33 Comparison of the machinability of ductile and gray irons (a) Metal removal rates (b) Tool life Source: Ref 20 Pearlitic Ductile Irons Compared With Pearlitic Gray Irons The test described in Example compared annealed ferritic ductile iron with pearlitic gray iron of slightly higher hardness Other data comparing pearlitic gray irons with pearlitic ductile irons show no great machinability differences when the irons are of similar hardness The comparison of tool life in the machining of ductile and gray irons is shown in Fig 33(b) Ductile Irons Compared With Malleable Cast Irons In another investigation, a comparison was made between ductile iron castings and malleable iron castings The machining operations included facing, boring, threading, and drilling There was no significant difference in machining costs between these two materials when the work was done on a production basis References cited in this section 19 Machining Data Handbook, Vol 1, 3rd ed., Metcut Research Associates, 1980 20 "Machinability Report," U.S Air Force, 1950 Ductile Iron Revised by Lyle R Jenkins, Ductile Iron Society; and R.D Forrest, Pechiney Electrometallurgie, Division Fonderie Welding Special materials and techniques are available for the repair welding of ductile iron castings, or for joining ductile iron to itself or to other ferrous materials such as steel, gray iron, or malleable iron Like the welding of other cast irons, the welding of ductile iron requires special precautions to obtain optimum properties in the weld metal and adjacent heat-affected zone The main objective is to avoid the formation of cementite in the matrix material, which makes the welded region brittle; but in ductile iron an additional objective, that of retaining a nodular form of graphite, is of almost equal importance The formation of martensite or fine pearlite can be removed by tempering A technique developed and patented by Oil City Iron Works uses a special ductile iron filler metal and a special welding flux that is introduced through a powder spray-type oxyacetylene welding torch In this technique, which is used predominantly for the cosmetic repair of ductile iron castings, parent metal is puddled under a neutral region of slightly reducing flame, and filler metal is added as the special flux is sprayed into the puddle through the torch A properly executed weld will be essentially free of eutectic carbides in the weld metal and will have a pearlitic matrix with bull's-eye ferrite surrounding the particles of spheroidal graphite Typically, the mechanical properties of the weld metal are very similar to those of the parent metal for all heattreated conditions: as-welded, annealed, normalized, or quenched and tempered The only possible exception is that the ductility of the weld metal may be slightly lower than that of equivalent parent metal at the lower hardnesses, such as those typical of the as-welded or annealed conditions Among other advantages, this process obtains a perfect color match with the cast metal; yields weld metal with composition, microstructure, and properties very close to those of the original casting; and minimizes the transition zone, the heat-affected zone, and any residual stresses As an alternative to the Oil City process, ductile iron can be welded with a high-nickel alloy, using the fluxcored arc welding (FCAW) process In flux-cored arc welding, a hollow wire with the composition 50Ni-44Fe4.25Mn-1.0C-0.6Si and containing a special flux is used as the electrode in standard FCAW equipment This method is used to join ductile iron to itself or to steel or other types of cast iron more often than it is used to effect the cosmetic repair of castings The mechanical properties of the high-nickel weld metal and of the adjacent heat-affected zone are usually equivalent to the properties of ASTM grade 65-45-12 ductile iron A major disadvantage of welding with the high-nickel alloy is that it does not respond to heat treatment, and thus weldments made with this alloy cannot be heat treated to obtain uniformly high strength levels, as can weldments made using the Oil City process Low-temperature welding rods and wire that have high wetting properties on cast iron base metals, are available This effects the joining of metals at such low temperatures that the base metal does not melt The composition of the weld metal is such that it has dimensional changes with temperature similar to those of ductile iron, thereby reducing stresses The color match is perfect, the hardness is low, the tensile strength is greater than 390 MPa (57 ksi), and the elongation is 25 to 30% The weld metal is suitable for tungsten inert gas welding operations The welding rods or wire are produced by Shichiho Metal Industrial Company Ltd Other methods for welding ductile iron include submerged arc welding and the use of austenitic consumable materials (see Ref 21, 22, 23 and the article "Welding of Cast Irons," in Welding, Volume of ASM Handbook, formerly 9th Edition Metals Handbook References cited in this section 21 D.L Olson, "Investigation of the MnO-SiO2-Oxides and MnO-SiO2-Fluorides Welding Flux Systems," DAAG29-77-G-0097, U.S Army Research Office, June 1978 22 M.A Davila, D.L Olson, and T.A Freese, Submerged Arc Welding of Ductile Iron, Trans AFS, 1977 23 M.A Davila and D.L Olson, The Development of Austenitic Filler Materials for Welding Ductile Iron, Paper 23, Welding Institute Reprint, Welding Institute, 1978 Ductile Iron Revised by Lyle R Jenkins, Ductile Iron Society; and R.D Forrest, Pechiney Electrometallurgie, Division Fonderie References R.B Gundlach and J.F Janowak, Approaching Austempered Ductile Iron Properties by Controlled Cooling in the Foundry, in Proceedings of the First International Conference on Austempered Ductile 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Iron: Your Means to Improved Performance, Productivity, and Cost, American Society for Metals, 1984 Lyle Jenkins, Ductile Iron An Engineering Asset, in Proceedings of the First International Conference on Austempered Ductile Iron: Your Means to Improved Performance, Productivity, and Cost, American Society for Metals, 1984 R.B Gundlach and J.F Janowak, A Review of Austempered Ductile Iron Metallurgy, in Proceedings of the First International Conference on Austempered Ductile Iron: Your Means to Improved Performance, Productivity, and Cost, American Society for Metals, 1984 P.A Blackmore and R.A Harding, The Effects of Metallurgical Process Variables on the Properties of Austempered Ductile Irons, in Proceedings of the Fist International Conference on Austempered Ductile Irons: Your Means to Improved Performance, Productivity, and Cost, American Society for Metals, 1984 C.R Loper, P Banerjee, and R.W Heine, Risering Requirements for Ductile Iron Castings in Greensand Moulds, Gray Iron News, May 1964, p 5-16 "The Fatigue Life of Cast Surface of Malleable and Nodular Iron," Bulletin 177, Metals Research and Development Foundation D.L Sponseller, W.G Scholz, and D.F Rundle, Development of Low-Alloy Ductile Irons for Service at 1200-1500 F, AFS Trans., Vol 76, 1968, p 353-368 W.S Pellini, G Sandoz, and H.F Bishop, Notch Ductility of Nodular Irons, Trans ASM, Vol 46, 1954, p 418-445 C Vishnevsky and J.F Wallace, The Effect of Heat Treatment on the Impact Properties of Ductile Iron, Gray Iron News, July 1962, p 5-10 R.K Nanstad, F.J Worzala, and C.R Loper, Jr., Static and Dynamic Toughness of Ductile Cast Iron, AFS Trans., Vol 83, 1975 G.N.J Gilbert, Tensile and Fatigue Tests on Normalized Pearlitic Nodular Irons, J Res., Vol (No 10), Feb 1957, p 498-504 R.C Haverstraw and J.F Wallace, Fatigue Properties of Ductile Iron, Gray Ductile Iron News, Aug 1966, p 5-19 H.D Merchant and M.H Moulton, Hot Hardness and Structure of Cast Irons, Br Foundryman, Vol 57 (Part 2), Feb 1964, p 62-73 C.F Walton, Ed., Gray and Ductile Iron Castings Handbook, Gray and Ductile Founders' Society, 1971 C.R Wilks, N.A Matthews, and R.W Kraft, Jr., Elevated Temperature Properties of Ductile Cast Irons, Trans ASM, Vol 47, 1954 F.B Foley, Mechanical Properties at Elevated Temperatures of Ductile Cast Iron, Trans ASME, Vol 78, 1956, p 1435-1438 C.C Reynolds, W.T Whittington, and H.F Taylor, Hardenability of Ductile Iron, AFS Trans., Vol 63, 1955, p 116-122 H.T Angus, Cast Iron: Physical and Engineering Properties, 2nd ed., Butterworths, 1976 Machining Data Handbook, Vol 1, 3rd ed., Metcut Research Associates, 1980 "Machinability Report," U.S Air Force, 1950 D.L Olson, "Investigation of the MnO-SiO2-Oxides and MnO-SiO2-Fluorides Welding Flux Systems," DAAG29-77-G-0097, U.S Army Research Office, June 1978 M.A Davila, D.L Olson, and T.A Freese, Submerged Arc Welding of Ductile Iron, Trans AFS, 1977 M.A Davila and D.L Olson, The Development of Austenitic Filler Materials for Welding Ductile Iron, Paper 23, Welding Institute Reprint, Welding Institute, 1978 Compacted Graphite Iron Doru M Stefanescu, The University of Alabama Introduction COMPACTED GRAPHITE (CG) cast iron is also referred to as vermicular graphite, upgraded, or semiductile cast iron (Ref 1) It has been inadvertently manufactured in the past in the process of producing ductile iron, as a result of undertreatment with magnesium or cerium Since 1965, after R.D Schelleng obtained a patent for its production, CG iron has occupied its rightful place in the family of cast irons The graphite morphology of CG iron is rather complex A typical scanning electron microscope photomicrograph of a compacted graphite particle etched out of the matrix is shown in Fig 1(a) It is seen that compacted graphite appears in clusters that are interconnected within the eutectic cells Classical optical metallography (Fig 1b) exhibits graphite that is similar to type IV ASTM A 247 graphite (see the article "Classification and Basic Metallurgy of Cast Iron" in this Volume) Compacted graphite appears as thicker, shorter-flake graphite In general, an acceptable CG iron is one in which at least 80% of the graphite is compacted graphite, there is a maximum of 20% spheroidal graphite (SG), and there is no flake graphite (FG) Fig Compacted graphite (a) SEM photomicrograph showing deep-etched specimen 200× (b) Optical photomicrograph This graphite morphology allows better use of the matrix, yielding higher strength and ductility than flake graphite cast iron Similarities between the solidification patterns of flake and compacted graphite iron explain the good castability of the latter, compared to ductile iron (ductile iron, which is also termed nodular iron or spheroidal graphite iron, is called SG iron in this article) Also the interconnected graphite provides better thermal conductivity and damping capacity than spheroidal graphite Reference E Nechtelberger, H Puhr, J.B von Nesselrode, and A Nakayasu, Paper presented at the 49th International Foundry Congress, International Committee of Foundry Technical Associations, Chicago, 1982 Compacted Graphite Iron Doru M Stefanescu, The University of Alabama Chemical Composition The range of acceptable carbon and silicon contents for the production of CG iron is rather wide, as shown in Fig Nevertheless, the optimum carbon equivalent (CE) must be selected as a function of section thickness, in order to avoid carbon flotation when too high a CE is used, or excessive chilling tendency, when too low a CE is used The manganese content can vary between 0.1 and 0.6%, depending on whether a ferritic or a pearlitic structure is desired Phosphorus content should be kept below 0.06% in order to obtain maximum ductility from the matrix The initial sulfur level should be below 0.025%, although techniques for producing CG iron from base irons with higher sulfur levels are now available (see the article "Compacted Graphite Irons" in Casting, Volume 15 of ASM Handbook, formerly 9th Edition Metals Handbook) Residual sulfur after liquid treatment is typically in the range of 0.01 to 0.02% Fig Optimum range for carbon and silicon contents for CG iron Source: Ref The change in graphite morphology from the flake graphite in the base iron to the compacted graphite in the final iron is achieved by liquid treatment with different minor elements These elements may include one or more of the following: magnesium, rare earths (cerium, lanthanum, praseodymium, and so on), calcium, titanium, and aluminum The amounts and combinations to be used are a function of the method of liquid treatment, base sulfur, section thickness, and so forth, and are discussed in Volume 15 of ASM Handbook, formerly 9th Edition Metals Handbook For example, Fig shows some typical correlations between treatment method (level of minor elements), initial sulfur level, and graphite shape when producing CG irons Spheroidizer ∆S range(a) for compacted iron, % Mg + Ce -0.0155 to -0.032 Mg + Ti > 0.10% -0.0155 to -0.042 Mg + Ti 0.05 - 0.1% + Al 0.2 - 0.3% -0.0110 to -0.055 Mg + Al > 0.35% -0.0060 to -0.35 (a) ∆S: final % S - 0.34 (% residual elements) - 1.33 (% Mg) Fig Optimum range of initial sulfur level as a function of type (figure) and amount (table) of minor elements used for graphite compaction The above table shows the sulfur range, ∆S, for compacted iron formation with different spheroidizers in an iron composition of 3.5% C, 2.1% Si, 0.75% Mn, and 0.03 to 0.08% P Source: Ref 1, Compacted graphite iron has a strong ferritization tendency Copper, tin, molybdenum, and even aluminum can be used to increase the pearlite/ferrite ratio Again, the optimum amounts of these elements for a particular matrix structure are largely a function of section size References cited in this section E Nechtelberger, H Puhr, J.B von Nesselrode, and A Nakayasu, Paper presented at the 49th International Foundry Congress, International Committee of Foundry Technical Associations, Chicago, 1982 H.H Cornell and C.R Loper, Jr., Trans AFS, Vol 93, 1985, p 435 R Elliott, Cast Iron Technology, Butterworths, 1988 Compacted Graphite Iron Doru M Stefanescu, The University of Alabama Castability The fluidity of cast iron is a function of its pouring temperature, composition, and eutectic morphology A higher temperature and higher CE result in better fluidity Everything else being equal, the fluidity of CG iron is intermediate between that of FG (highest) and SG (lowest) iron (Ref 1) However, because CG iron has a higher strength than FG iron for the same CE, high-CE compositions of CG iron can be used for the pouring of thin castings Shrinkage Characteristics With CG irons, obtaining sound castings free from external and internal shrinkage porosity is easier than with SG irons and slightly more difficult than with FG irons This is because the tendency for mold wall movement also lies between that of SG and FG irons In relative numbers, solidification expansion has been found to be 4.4 for SG iron and to 1.8 for CG iron if FG iron is (Ref 4) Because of the rather low shrinkage of CG iron, it can sometimes be cast riserless Expensive pattern changes are therefore not necessary when converting from gray iron to CG iron because the same gating and risering techniques can be applied Chilling Tendency Although many believe that the chilling tendency of CG iron is also intermediate between that of FG (lowest) and SG (highest) irons, this is not true Figure shows the influence of nodularity on the structure of chill pins cast in air set molds (Ref 5) It can be seen that the highest chilling tendency is achieved for irons with nodularities between and 64% In other words, the chilling tendency of CG iron is higher than that of both SG and FG iron This correlates with cooling curve data (see the article "Compacted Graphite Irons" in Casting, Volume 15 of ASM Handbook, formerly 9th Edition Metals Handbook) and is explained by the combination of a low nucleation rate and low growth rate occurring during the solidification of CG iron Fig Influence of graphite shape over the chilling tendency of cast iron Type A graphite flake: uniform distribution and random orientation Type D graphite flake: interdendritic segregation and random orientation (see the article "Classification and Basic Metallurgy of Cast Iron" in this Volume) Source: Ref References cited in this section E Nechtelberger, H Puhr, J.B von Nesselrode, and A Nakayasu, Paper presented at the 49th International Foundry Congress, International Committee of Foundry Technical Associations, Chicago, 1982 D.M Stefanescu, I Dinescu, S Craciun, and M Popescu, "Production of Vermicular Graphite Cast Irons by Operative Control and Correction of Graphite Shape," Paper 37 presented at the 46th International Foundry Congress, Madrid, 1979 D.M Stefanescu, F Martinez, and I.G Chen, Trans AFS, Vol 91, 1983, p 205 Compacted Graphite Iron Doru M Stefanescu, The University of Alabama Mechanical Properties at Room Temperature The in-service behavior of many structural parts is a function not only of their mechanical strength, but also of their deformation properties Thus it is not surprising to find that many castings fail not because of insufficient strength, but because of a low capacity for deformation This is especially true under conditions of rapid loading and/or thermal stress Particularly sensitive to such loading are casting zones that include some defects or abrupt changes in section thickness The elongation values of about 1% obtainable with high-strength gray iron are insufficient for certain types of applications such as diesel cylinder heads (Ref 6) Compacted graphite irons have strength properties close to those of SG irons, at considerably higher elongations than those of FG iron, and with intermediate thermal conductivities Consequently, they can successfully outperform other cast irons in a number of applications The main factors affecting the mechanical properties of CG irons both at room temperatures and at elevated temperatures are: • • • Composition Structure (nodularity and matrix) Section size In turn, the structure is heavily influenced by processing variables such as the type of raw materials, preprocessing of the melt (superheating temperature, holding time, desulfurization), and liquid treatment (graphite compaction and postinoculation) Tensile Properties and Hardness A comparison between some properties of FG, CG, and SG irons is given in Table A listing of tensile properties of various CG irons produced by different methods is given in Table Table Comparison of properties of cerium-treated CG iron with FG iron of the same chemical composition, high-strength pearlitic FG iron, and ferritic SG iron in the as-cast condition Property High-strength pearlitic FG iron (100% pearlite, 100% FG)(a) FG iron (100% pearlite, 100% FG)(b) Ce-treated CG iron (>95% ferrite, >95% CG)(b) SG iron (100% ferrite, 80% SG, 20% poor SG)(b) Chemical composition, % 3.10 C, 2.10 Si, 0.60 Mn 3.61 C, 2.49 Si, 0.05 Mn 36.1 C, 2.54 Si, 0.05 Mn 3.56 C, 2.72 Si, 0.05 Mn Tensile strength, MPa (ksi) 317 (46) 110 (16) 336 (48.7) 438 (63.5) 0.2% proof stress, MPa (ksi) 257 (37.3) 285 (41.3) Elongation, % 6.7 25.3 Modulus of elasticity, GPA (106 psi) 108 (15.7) 96.9 (14.05) 158 (22.9) 176 (25.5) Brinell hardness, HB 200 156 150 159 at 20 °C (68 °F) 9.32 (6.87) 24.5 (18.1) at -20 °C (-4 °F) 6.57 (4.85) 9.81 (7.23) at -40 °C (-40 °F) 7.07 (5.21) 6.18 (4.56) Charpy V-notched-bar impact toughness, J (ft · lbf) Charpy impact bend toughness, J (ft · lbf) at 20 °C (68 °F) 4.9 2.0 32.07 (23.7) 176.5 (130.2) at -20 °C (-4 °F) 26.48 (19.5) 148.1 (109.2) at -40 °C (-40 °F) 26.67 (19.7) 121.6 (89.7) Rotating-bar fatigue strength, MPa (ksi) 127.5 (18.5) 49.0 (7.1) 210.8 (30.6) 250.0 (36.3) Thermal conductivity, W/(cm · K) 0.419 0.423 0.356 0.327 Source: Ref (a) Mechanical properties determined from a sample with a section size 30 mm (1.2 in.) in diameter (b) Mechanical properties determined from a Y block 23 mm (0.9 in.) section Table Tensile properties, hardness, and thermal conductivity of various CG irons at room temperature Structural condition(a) Graphite type Tensile strength 0.2% proof stress MPa Degree of saturation, S C (b) ksi MPa ksi Irons treated with additions of cerium As-cast ferrite (>95% F) 1.04 95% CG, 5% SG 336 48.7 257 37.3 Ferritic-pearlitic (>5% P) 1.04 95% CG, 5% SG 298 43.2 224 32.5 As-cast ferrite (90% F, 10% P) 1.00 85% CG, 15% SG 371 53.8 267 38.7 100% ferrite 1.00 85% CG, 15% SG 338 49.0 245 35.5 100% ferrite 1.04-1.09 CG 365 ± 63 53 ± 278 ± 42 40 ± Ferritic-pearlitic (>90% F, 90% CG 300-400 43-58 250-300 36-43 Ferritic-pearlitic (85% F) 1.04 70% CG, 30% SG 320 46.4 242 35 Pearlitic (90% P, 10% F) 90% CG 400-550 58-80 320-430 46-62 Pearlitic (95% P, 5% F) 1.02 80% CG, 20% SG 410 59.5 338 49 As-cast ferrite (0.004% Ce, 95% F) 6.7 158 22.9 35.6 150 Ferritic-pearlitic (>5% P) 5.3 144 20.9 38.5 128 As-cast ferrite (90% F, 10% P) 5.5 137 19.9 100% ferrite 8.0 140 100% ferrite 7.2 ± 4.5 138-156 Ferritic-pearlitic (>90% F,