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Ch09 Notes

Dec 02, 2015

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Notes for IUPUI ME 344

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    Iron Carbide Phase Diagram

    Figure 9.6

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    Creating Pearlite

    Figure 9.7

    Figure 9.8

    After W. F. Smith, The Structure and Properties of Engineering Alloys, 2nd ed.,McGraw-Hill, 1981, p.8

    Hypoeutectoid Plain Carbon Steel

    Figure 9.9 Figure 9.10

    Pearlite

    After W. F. Smith, The Structure and Properties of Engineering Alloys, 2nd ed.,McGraw-Hill, 1981, p.10

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    Hypereutectoid Plain Carbon Steel

    Figure 9.11After W. F. Smith, The Structure and Properties of Engineering Alloys, 2nd ed.,McGraw-Hill, 1981, p.12.

    Proeutectoid Cementite (white)

    Crystal Structure

    Figure 9.17 Figure 9.19After E. R. Parker and V. F. Zackay Strong and Ductile Steels, Sci.Am.,November 1968, p.36; Copyright by Scientific American Inc; all rights reserved

    AusteniteFCC

    Slightly distorted

    MartensiteBCC

    Distorted (long in c)BCC- BC Tetragonal

    Alpha FerriteBCC

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    Microstructure of Fe C Martensites

    Figure 9.13

    After A. R. Marder and G. Krauss, as presented in Hardenebility Concepts with Applications to Steel, AIME, 1978, p. 238.

    Bainite

    Figure 9.24

    After H. E. McGannon(ed.), The Making Shaping and Treating of Steel, 9th ed., United States Steel Corp., 1971

    Hot quenched 550-350 Hot quenched 350 - 250

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    Crystal Formation Requires Time.

    After W. F. Smith, The Structure and Properties of Engineering Alloys, McGraw-Hill, 1981, p.14

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    Isothermal Transformation (IT)Diagram

    Figure 9.22

    After W. F. Smith, The Structure and Properties of Engineering Alloys, McGraw-Hill, 1981, p.14

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    IT Diagrams for Noneutectoid Steels

    Figure 9.25After R. A. Grange, V. E. Lambert, and J. J. Harrington, Trans, ASM, 51:377(1959)

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    Continuous Cooling-Transformation Diagram

    Figure 9.26After R. A. Grange and J. M. Kiefer, Alloying Elements in Steel, ASM 2nd ed., 1966, p.254.

    Continuous Cooling-Transformation Diagram

    Figure 9.27After R. A. Grange and J. M. Kiefer, Alloying Elements in Steel, ASM 2nd ed., 1966, p.254.

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    Heat Treatments

    Annealing

    Normalizing

    Quenching

    Tempering

    Austenitizing

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    Tempering of Plain Carbon Steel

    Tempering TemperatureBelow 200 C200 700 0C400 700 0C

    StructureEpsilon CarbideCementite (rod-like)Cementite (Spheroidite)

    Figure 9.31From Suiting the heat Treatment to the job, United States Steel Corp., 1968, p.34.

    Spheroidite sphere like cementite particlesmost ductile high energy productionsince keep at 700C for 30 hours or moreresults in softer steel than full anneal

    Effects of Tempering

    Figure 9.32After JE. C. Bain, and H. W. Paxton, Alloying Elements in Steel, 2nd ed., American Society for Metals, 1996 p.38.

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    Classification

    Classification of Alloy Steels First two digits: Principle alloying element. Last two digits: % of carbon.

    Source: Alooy Steel: Semifinished; Hot-Rolled and Cold-Finished Bars, American Iron and Steel Institute, 1970.

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    Hardenability

    Weldability

    Machineability

    In General Choose between:1. Load Bearing member yield strength & toughness2. Wear application 60HRC on surface with required thickness3. Through hardening (C > 0.3%)4. High-strength, low-alloy weldability and structural uses

    Typical ranges in alloy steels (%) Principal effects

    Aluminum

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    Mechanical Properties of Low Alloy Steels

    4820

    Table 9.6

    Treatment E (Gpa)

    Yield (Mpa)

    Ultimate

    Elongation

    Microstruct

    1 Normalized 205 475 793 22.7% Fine Pearlite

    2 Annealed 830 C 11C/hr to 650C then air cooled

    3 Oil quenched from 845 with 540 C temper

    4 Oil quench from 845 with 595 C temper

    5 Oil quench from 845 with 650 C temper

    5140 Steel

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    Aluminum

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    Effects of Aging on Strength

    Figure 9.43

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    Copper

    Stainless Steel

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    Cast Iron

    White Cast iron

    Iron Carbide

    Pearlite

    Figure 9.59

    Courtesy of central Foundry

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    Gray Cast Iron

    GraphiteFlakes

    Figure 9.60 Figure 9.61

    After Metals Handbook, vol. 7, 8th ed., American Society for Metals, 1972, p.82.

    Ductile Cast iron

    Figure 9.63After Metals Handbook, vol. 7, 8th ed., American Society for Metals, 1972, p.88.

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    Malleable Cast Iron

    Figure 9.65After Metals Handbook, vol. 7, 8th ed., American Society for Metals, 1972, p.95.

    Magnesium Alloys

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    Titanium Alloys

    Nickel AlloysAlnico (aluminium, cobalt; used in magnets)Alumel (manganese, aluminium, silicon)Chromel (chromium)Cupronickel (bronze, copper)Ferronickel (iron)German silver (copper, zinc)Hastelloy (molybdenum, chromium, sometimes tungsten)Inconel (chromium, iron)Monel metal (copper, iron, manganese)Nichrome (chromium)Nickel-carbon (carbon)Nicrosil (chromium, silicon, magnesium)Nisil (silicon)Nitinol (titanium, shape memory alloy)

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    Shape Memory Effect

    Heated(Austenite)

    Cooled(Martensite)

    Deformed(Martensite) Heated

    (Austenite)

    NiTi

    NiTi

    Amorphous Metals

    crystalline Amorphous

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