ME330 Manufacturing Processes - PowerPoint PPT Presentation

Title: ME330 Manufacturing Processes


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ME-330Manufacturing Processes

• Instructor Chris Zhang
• E-mail Chris.Zhang_at_Usask.ca
• Marker
• E-mail

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Course Objective Provide introduction to
processes involved in manufacturing of parts and
products and to relating these processes to
basic engineering concepts product designs
Technical Nature of the Course 1.Theoretical
foundation for mathematical analysis of
various processes. 2. Classification and
description of various technologies 3. The
equipment
Text Fundamentals of Modern Manufacturing
Materials, Processes, and SystemsMikell P.
Groover, Prentice Hall,  ISBN 0 - 13 -312182-8
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Evaluation Assignment                         
           10 Quiz                            
                     25 Participation         
                            10 Case
study                                       20
Final exam (written, open book)       35
                                       
Total       100
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Metals Phase diagram
Property high stiffness, better toughness,
good electrical conductivity, good thermal
conductivity
Why metals have these nice properties

• structures at atomic level

Fig.1.1
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Metals Phase diagram
Ways to change the structure temperature,
alloying, chemistry, mechanical
Pure metals and their Alloys
- Gold, silver, and copper may exist in
applications as their pure form, but most of
metals are alloyed. - An alloy is a metal
comprised of two or more elements, at least one
of which is metallic. Two main categories of
alloys are (1) solid solutions and (2)
intermediate phase.
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Metals Phase diagram
Solid solutions one element dissolved in another
to form single-phase solution Phase-Any
homogeneous mass, metal with grains having same
lattice structure
Types Substitutional and Interstitial
Fig.1.2
- Solid solution alloy structure stronger and
harder
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Metals Phase diagram

• Conditions for substitutional solid solutions
  possible
• The atomic radii of the two elements similar
• Their lattice types must be the same
• The lower valency metal becomes the solvent
• Their chemical affinity is small

Example BRASS (ZINC in COPPER)
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Metals Phase diagram
Interstitial solid solution Atoms of dissolving
element fit into vacant spaces between base metal
atoms in lattice structure - Solute atoms small
compared to Solvent atoms
Example Carbon dissolved in Iron to form STEEL
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Metals Phase diagram

• Intermediate phases
• Every element has a limit for its solubility of
  another element
• When element A completely dissolved into another
  element B, the whole system is one phase of that
  solid solution.

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Metals Phase diagram

• Intermediate phases
• When the amount of the dissolving element in the
  alloy exceeds the solid solubility limit of the
  base metal, a second phase forms in the alloy.

Intermediate phase
Its properties are between two pure elements
Here, the system has two elements (A,B) and two
phases intermediate phase and solid solution
(A,B)
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Metals Phase diagram
Phase diagram
A means to represent the phase or status of a
metal alloy system with respect to (1)
composition and (2) temperature
P f (T, C)
(a) Amount of dissolving element A and amount of
solvent element B ? (b) Among of phase 1 and
amount of phase 2 ?
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Metals Phase diagram
Fig. 1.3 is a copper-nickel alloy system
Fig.1.3
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Metals Phase diagram
The following things are known from Fig.1.3

• Pure copper melts at 1981 F
• Pure nickel melts at 2651 F
• The system is a solid solution throughout
• Below solidus line solid
• Above liquidus line liquid
• Between, two phases solid and liquid

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Metals Phase diagram

• - The overall composition of the alloy (i.e.,
  amount of copper and amount of nickel) is given
  by its position along the horizontal axis.
• The compositions of the liquid and solid phases
  are not the same (Cu-Ni ratio in Solid phase NOT
  EQUAL to Cu-Ni ratio in Liquid phase)
• - Ex 1. 50 copper-nickel and at 1260 deg C, see
  Fig.1.3. Find the compositions of the solid and
  liquid.
• Solution draw a horizontal line, which
  intersects the liquidus and solidus lines,
  respectively, see Fig.1.3.

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Metals Phase diagram
Obtain 62 Ni in solid, 36 Ni in
liquid When reduce temperature at 50-50 point to
the solidus line, we obtain 50 Ni in solid and
26 Ni in liquid. The is the result of the
assumption made in the phase diagram, i.e., the
equilibrium state there is sufficient time given
(for diffusion) to the whole system to meet that
which is indicated by the intersection point
along the liquidus. In practice, there is a
situation called segregation when the liquid
freezes
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Metals Phase diagram
segregation The first liquid to solidify has a
composition that is rich in the metal element
with the higher melting point. Then, as
additional metal solidified, its composition is
different from that of the first metal to freeze.
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Metals Phase diagram
Inverse lever rule (determine amounts of phases
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L phase proportion CS/(CSCL) S phase
proportion LS/(CSCL)
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Metals Phase diagram
Remark 1.1 The method of determining the
chemical composition of phases and the amounts of
each phase are applicable to the solid region of
the phase diagram as well as to the
liquidus-solidus region. When only one phase is
present (in Fig.1.3), this is in the entire solid
region), the composition of the phase is its
aggregate composition under equilibrium
conditions, and the inverse lever rule does not
apply since there is only one phase.
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Metals Phase diagram
Tin-lead system a more complicated phase
diagram, see Fig. 1.4.
Fig.1.4
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Metals Phase diagram

• New features (Fig.1.4)
• Presence of two new solids ? and ?
• Eutectic point, which has the lowest melting
  point
• Pure tin and lead have the highest melting point
  any of their alloys melt at lower temperature.

Ex 2 determine the compositions in two
corresponding phases for the aggregate
composition, 25 , at temperature 500 F.
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Metals Phase Diagram for Iron and Carbon
1. Iron Ferrous Metals, Fe
Iron Carbon Alloys Steel and Cast iron BCC
structure
2. Iron Carbon phase diagram (Fig.2.1)

• Pure iron, melting point 2802 F
• From room temp. to melting, several solid phases
  transforms a -gt ? -gt d

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Metals Phase diagram for Iron and Carbon
Fe3C
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Metals Phase diagram for Iron and Carbon

• Iron pure iron (99.99 ),
• ingot iron (some carbon, 0.1 impurities),
• wrought iron (3 slug with low carbon).
• Solubility of carbon in iron will depend on
  solid phases of iron Ferrite 0.02 Austenite
  2.1
• Steel 0.02 2.1 Cast iron 2.1-4
• Cementite, Fe3C hard and brittle
• Carbon an element increasing strength Fe is
  soft.

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Metals Phase diagram for Iron and Carbon

• 3. Steel
• - Steel is an alloy of iron that contains carbon
  ranging by weight between 0.02 and 2.11
• It often includes other alloying ingredients as
  well manganese, chromium, nickel, molybdenum
• classification of steels
• plain carbon, low-alloy, stainless, tool

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Metals Phase diagram for Iron and Carbon
3. Steel plain carbon steel low-carbon (lt0.2),
medium-carbon (0.2lt and lt0.5), high-carbon
(gt0.5).
Low-alloy steel Cr, Mn, Mo, Ni, V
Stainless steels highly alloyed steels, Cr 15,
Ni
Tool steel highly alloyed steels designed for
use as industrial cutting tools, dies, and molds.
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Metals Nonferrous metals
1. Metals
Ferrous and nonferrous
2. Nonferrous
Aluminum, copper, magnesium, nickel, titanium,
and zinc and their alloys.
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General feature of non-ferrous metals

• Strength is not as good as the steel
• Corrosion resistance and/or strength-to-weight
  ratios higher
• Lower electrical resistance copper
• Higher thermal conductivity aluminum
• Lower melting point Zinc (die casting)

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• Superalloys
• - Substantial amount of 3 or more metals
  rather than one base metal alloying elements
• Processing of metals
• - Shaping- casting, forming, material removel
• - Assembly
• - Finishing process- electroplating, painting
• - Property Enhancement- Cold working, Heat
• Treatment