MECHANICALPROCESSES

Polymers

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Material Science
Overview
Characteristics
Comparisons
Development Timeline

Selection Criteria
Applications
Flow Characteristics
Data Sheet Primer
Glossary
Creep
Glass Transition Temperature
Heat Deflection Temperature
Mold Shrinkage
more...

Thermoplastics
ABS
Fluoropolymers
Polyacetal
Polyamide
Polycarbonate
Polyethylene
Polysulfone
more... Thermosets
Epoxy
Phenolic Resin
Polyimide
Polyurethane
Silicone
more

Common Materials

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Introduction :-
Properties of common solid materials are divided into following categories:
• Physical properties: Density, melting and boiling temperature.
• Mechanical Properties: Including basic mechanical properties, such as elastic modulus, shear modulus, Poisson's ratio, and mechanical strength properties, i.e., yielding stress, ultimate stress, elongation.
• Thermal Properties: Coefficient of thermal expansion, thermal conductivity.
• Electric Properties: Electric resistivity.
• Acoustic Properties: Compression wave velocity, shear wave velocity, bar velocity.

Note: 1. All properties are under 1 atm (1.01325×105 Pa; 760 mmHg; 14.6959 psi) and at room temperature 25 ºC (77 ºF) unless specified otherwise.
2. Further information on a specific material can be obtained by clicking the name of that particular material in the following table.
3. Users who prefer Standard or other unit systems rather than the SI units, click the amount (number) of the specific material property for unit conversion.
4. Materials in different phases at room temperature: Liquid, Gas.

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Physical Properties

Material Density
(×1000 kg/m3) Melting Point
(ºC) Boiling Point
(ºC)
Aluminum [Al] 2.71 660.3 2519
Aluminum Alloy 2.64 - 2.8 565.0 - 660.0 -
Brass 8.4 - 8.75 930.0 -
Brass; Noval 8.4 - -
Brass; Red (80% Cu, 20% Zn) 8.75 1000 -
Brick 1.8 - 2.4 - -
Bronze; Regular 7.8 - 8.8 1050 -
Bronze; Manganese 8.3 - -
Carbon [C] 2.25 4492 3642
Ceramic 2 - 3 3870 -
Concrete 2.3 - 2.4 - -
Copper [Cu] 8.94 1085 2562
Copper Alloy 8.23 925.0 -
Cork 0.15 - 0.2 - -
Glass 2.4 - 2.8 - -
Gold [Au] 19.32 1064 2856
Iron [Fe] 7.87 1538 2861
Iron (Cast) 7 - 7.4 - -
Iron (Wrought) 7.4 - 7.8 - -
Lead [Pb] 11.3 327.5 1749
Magnesium [Mg] 1.74 650.0 1090
Magnesium Alloy 1.77 1246 2061
Monel (67% Ni, 30% Cu) 8.84 1330 -
Nickel [Ni] 8.89 1455 2913
Nylon; Polyamide 1.1 - -
Platinum [Pt] 21.4 1768 3825
Rubber 0.96 - 1.3 - -
Silicon [Si] 2.33 1382 -
Silver [Ag] 10.49 961.8 2162
Solder; Tin-Lead 8.17 - 11.34 215.0 -
Steel 7.85 1425 -
Stone; Granite 2.6 - -
Stone; Limestone 2 - 2.9 - -
Stone; Marble 2.6 - 2.9 - -
Stone; Quartz 2.6 - -
Tin [Sn] 7.3 231.9 2602
Titanium [Ti] 4.54 1668 3287
Titanium Alloy 4.51 - -
Tungsten [W] 19.3 3422 5555
Wood; Ash 0.56 - 0.64 - -
Wood; Douglas Fir 0.48 - 0.56 - -
Wood; Oak 0.64 - 0.72 - -
Wood; Southern Pine 0.55 - 0.64 - -
Zinc [Zn] 7.14 419.5 907.0

other alloy

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Carbon Steels
Low-Carbon Steels
Medium-Carbon Steels
High-Carbon Steels
ANSI 10xx 11xx 12xx 15xx
more...

Alloy Steels
Standard Alloy Steels
H-Steels
HSLA
ANSI 13xx 4xxx 5xxx 8xxx 9xxx
more...
Stainless Steels
Austenitic Steels
Martensitic Steels
Ferritic Steels
Type 2xx 3xx 4xx 5xx
more...

Tool Steels
High Speed
Cold Work
Hot work
ANSI M T H A S
more...

Aluminum Alloys
Cast Aluminum
Wrought Aluminum
AA 1xxx 2xxx 5xxx 6xxx 7xxx
more...

Copper Alloys
Cast Copper
Wrought Copper
Brasses
Bronzes
UNS C1xxxx C4xxxx C8xxxx C9xxxx
more...
Titanium Alloys
Commercially Pure
Alpha Alloys
Beta Alloys
more...

Magnesium Alloys
Castings
Bars and Shapes
Sheets and Plates

copper alioys

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General Information

Copper is one of the most useful metals known to man, and it was one of the first to be utilized. Copper is a reddish-yellow material and is extremely ductile. Copper has a face-centered-cubic (fcc) crystal structure and has the second best electrical conductivity of the metals, second only to silver compared to which it has a conductivity of 97%. The thermal conductivity of copper is very high falling in between silver and gold. There are almost 400 different copper alloys depending on the commercial product made; rods, plates, sheets, strips, tubes, pipes, extrusions, foils, forgings, wires, and castings from foundries.

Cast Copper Alloys

Cast copper alloys generally have a great range of alloying elements than wrought alloys because of the nature of the casting process. The cast brasses consist of of copper-zinc-tin alloys (red, semi-red, and yellow). The cast bronzes consist of manganese bronzes (high-strength yellow brasses), leaded manganese bronze alloys (leaded high-strength yellow brasses), and copper-zinc-silicon alloys (silicon brasses and bronzes). There are four main families in the cast bronze alloys; copper-tin-lead, copper-tin-nickel, copper-tin, and copper-aluminum alloys.

Wrought Copper Alloys

Wrought alloys produced in a variety of different methods, including annealed, cold worked, hardened by heat treatments, or stress relieved. There are four main families of wrought copper (see table above); copper and high-copper alloys, brasses, bronzes, and copper nickel & nickel-silver alloys.

UNS Designations

UNS Numbers Types Alloy Names
C10000-C19999: Wrought Coppers, High-Copper Alloys
C20000-C49999: Wrought Brasses
C50000-C59999: Wrought Phosphor Bronzes
C60600-C64200: Wrought Aluminum Bronzes
C64700-C66100: Wrought Silicon Bronzes
C66400-C69800: Wrought Brasses
C70000-C79999: Wrought Copper nickels, nickel silvers
C80000-C82800: Cast Coppers, High-Copper Alloys
C83300-C85800: Cast Brasses
C86100-C86800: Cast Manganese Bronzes
C87200-C87900: Cast Silicon Bronzes and Brasses
C90200-C94800: Cast Tin Bronzes
C95200-C95800: Cast Aluminum Bronzes
C96200-C97800: Cast Copper Nickels, Nickel Silvers
C98200-C98800: Cast Leaded Copper
C99300-C99750: Cast Special Alloys

Aluminum alloy

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General Information

Aluminum is a silverish white metal that has a strong resistance to corrosion and like gold, is rather malleable. It is a relatively light metal compared to metals such as steel, nickel, brass, and copper with a specific gravity of 2.7. Aluminum is easily machinable and can have a wide variety of surface finishes. It also has good electrical and thermal conductivities and is highly reflective to heat and light.

Characteristics

At extremely high temperatures (200-250°C) aluminum alloys tend to lose some of their strength. However, at subzero temperatures, their strength increases while retaining their ductility, making aluminum an extremely useful low-temperature alloy.
Aluminum alloys have a strong resistance to corrosion which is a result of an oxide skin that forms as a result of reactions with the atmosphere. This corrosive skin protects aluminum from most chemicals, weathering conditions, and even many acids, however alkaline substances are known to penetrate the protective skin and corrode the metal.

Aluminum also has a rather high electrical conductivity, making it useful as a conductor. Copper is the more widely used conductor, having a conductivity of approximately 161% that of aluminum. Aluminum connectors have a tendency to become loosened after repeated usage leading to arcing and fire, which requires extra precaution and special design when using aluminum wiring in buildings.

Aluminum is a very versatile metal and can be cast in any form known. It can be rolled, stamped, drawn, spun, roll-formed, hammered and forged. The metal can be extruded into a variety of shapes, and can be turned, milled, and bored in the machining process. Aluminum can riveted, welded, brazed, or resin bonded. For most applications, aluminum needs no protective coating as it can be finished to look good, however it is often anodized to improve color and strength.

steel

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Steel is the common name for a large family of iron alloys which are easily malleable after the molten stage. Steels are commonly made from iron ore, coal, and limestone. When these raw materials are put into the blast furnace, the result is a "pig iron" which has a composition of iron, carbon, manganese, sulfur, phosphorus, and silicon.
As pig iron is hard and brittle, steelmakers must refine the material by purifying it and then adding other elements to strengthen the material. The steel is next deoxidized by a carbon and oxygen reaction. A strongly deoxidized steel is called "killed", and a lesser degrees of deoxodized steels are called "semikilled", "capped", and "rimmed".

Steels can either be cast directly to shape, or into ingots which are reheated and hot worked into a wrought shape by forging, extrusion, rolling, or other processes. Wrought steels are the most common engineering material used, and come in a variety of forms with different finishes and properties.

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Standard Steels

According to the chemical compositions, standard steels can be classified into three major groups: carbon steels, alloy steels, and stainless steels:
Steels Compositions
Carbon Steels Alloying elements do not exceed these limits: 1% carbon, 0.6% copper, 1.65% manganese, 0.4% phosphorus, 0.6% silicon, and 0.05% sulfur.
Alloy Steels Steels that exceed the element limits for carbon steels. Also includes steels that contain elements not found in carbon steels such as nickel, chromium (up to 3.99%), cobalt, etc.
Stainless Steels Contains at least 10% chromium, with or without other elements. Based on the structures, stainless steels can be grouped into three grades:
Austenitic: Typically contains 18% chromium and 8% nickel and is widely known as 18-8. Nonmagnetic in annealed condition, this grade can only be hardened by cold working.

Ferritic: Contains very little nickel and either 17% chromium or 12% chromium with other elements such as aluminum or titanium. Always magnetic, this grade can be hardened only by cold working.

Martensitic: Typically contains 12% chromium and no nickel. This grade is magnetic and can be hardened by heat treatment.

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Tool Steels

Tool steels typically have excess carbides (carbon alloys) which make them hard and wear-resistant. Most tool steels are used in a heat-treated state, generally hardened and tempered.
There are a number of categories assigned by AISI (American Iron and Steel Institute), each with an identifying letter:

W: Water-Hardening
S: Shock-Resisting
O: Cold-Work (Oil-Hardening)
A: Cold-Work (Medium-Alloy, Air-Hardening)
D: Cold-Work (High-Carbon, High-Chromium)
L: Low-Alloy
F: Carbon-Tungsten
P: P1-P19: Low-Carbon Mold Steels
P20-P39: Other Mold Steels
H: H1-H19: Chromium-Base Hot Work
H20-H29: Tungsten-Base Hot Work
H40-H59: Molybdenum-Base Hot Work
T: High-Speed (Tungsten-Base)
M: High-Speed (Molybdenum-Base)

materials

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Elements

Element Name Symbol Atomic Number Atomic Weight
Actinium Ac 89 [227]
Aluminum Al 13 26.981539
Americium Am 95 [243]
Antimony Sb 51 121.76
Argon Ar 18 39.948
Arsenic As 33 74.92159
Astatine At 85 [210]
Barium Ba 56 137.327
Berkelium Bk 97 [247]
Beryllium Be 4 9.012182
Bismuth Bi 83 208.98037
Boron B 5 10.811
Bromine Br 35 79.904
Cadmium Cd 48 112.411
Calcium Ca 20 40.078
Californium Cf 98 [251]
Carbon C 6 12.011
Cerium Ce 58 140.115
Cesium Cs 55 132.90543
Chlorine Cl 17 35.4527
Chromium Cr 24 51.9961
Cobalt Co 27 58.9332
Copper Cu 29 63.546
Curium Cm 96 [247]
Dubnium Db 105 [262]
Dysprosium Dy 66 162.5
Einsteinium Es 99 [252]
Erbium Er 68 167.26
Europium Eu 63 151.965
Fermium Fm 100 [257]
Fluorine F 9 18.9984032
Francium Fr 87 [223]
Gadolinium Gd 64 157.25
Gallium Ga 31 69.723
Germanium Ge 32 72.61
Gold Au 79 196.96654
Hafnium Hf 72 178.49
Helium He 2 4.002602
Holmium Ho 67 164.93032
Hydrogen H 1 1.00794
Indium In 49 114.818
Iodine I 53 126.90447
Iridium Ir 77 192.217
Iron Fe 26 55.845
Krypton Kr 36 83.8
Lanthanum La 57 138.9055
Lawrencium Lr 103 [262]
Lead Pb 82 207.2
Lithium Li 3 6.941
Lutetium Lu 71 174.967
Magnesium Mg 12 24.305
Manganese Mn 25 54.93805
Mendelevium Md 101 [258]
Mercury Hg 80 200.59
Molybdenum Mo 42 95.94
Neodymium Nd 60 144.24
Neon Ne 10 20.1797
Neptunium Np 93 [237]
Nickel Ni 28 58.6934
Niobium Nb 41 92.90638
Nitrogen N 7 14.00674
Nobelium No 102 [259]
Osmium Os 76 190.23
Oxygen O 8 15.9994
Palladium Pd 46 106.42
Phosphorus P 15 30.973762
Platinum Pt 78 195.08
Plutonium Pu 94 [244]
Polonium Po 84 [209]
Potassium K 19 39.0983
Praseodymium Pr 59 140.90765
Promethium Pm 61 [145]
Protactinium Pa 91 231.03588
Radium Ra 88 [226]
Radon Rn 86 [222]
Rhenium Re 75 186.207
Rhodium Rh 45 102.9055
Rubidium Rb 37 85.4678
Ruthenium Ru 44 101.07
Rutherfordium Rf 104 [261]
Samarium Sm 62 150.36
Scandium Sc 21 44.95591
Selenium Se 34 78.96
Silicon Si 14 28.0855
Silver Ag 47 107.8682
Sodium Na 11 22.989768
Strontium Sr 38 87.62
Sulfur S 16 32.066
Tantalum Ta 73 180.9479
Technetium Tc 43 [98]
Tellurium Te 52 127.6
Terbium Tb 65 158.92534
Thallium Tl 81 204.3833
Thorium Th 90 232.0381
Thulium Tm 69 168.93421
Tin Sn 50 118.71
Titanium Ti 22 47.867
Tungsten W 74 183.84
Uranium U 92 238.0289
Vanadium V 23 50.9415
Xenon Xe 54 131.29
Ytterbium Yb 70 173.04
Yttrium Y 39 88.90585
Zinc Zn 30 65.39
Zirconium Zr 40 91.224

Rapid Prototyping

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Rapid Prototyping (RP) can be defined as a group of techniques used to quickly fabricate a scale model of a part or assembly using three-dimensional computer aided design (CAD) data. What is commonly considered to be the first RP technique, Stereolithography, was developed by 3D Systems of Valencia, CA, USA. The company was founded in 1986, and since then, a number of different RP techniques have become available.

Rapid Prototyping has also been referred to as solid free-form manufacturing, computer automated manufacturing, and layered manufacturing. RP has obvious use as a vehicle for visualization. In addition, RP models can be used for testing, such as when an airfoil shape is put into a wind tunnel. RP models can be used to create male models for tooling, such as silicone rubber molds and investment casts. In some cases, the RP part can be the final part, but typically the RP material is not strong or accurate enough. When the RP material is suitable, highly convoluted shapes (including parts nested within parts) can be produced because of the nature of RP.

There is a multitude of experimental RP methodologies either in development or used by small groups of individuals. This section will focus on RP techniques that are currently commercially available, including Stereolithography (SLA), Selective Laser Sintering (SLS®), Laminated Object Manufacturing (LOM™), Fused Deposition Modeling (FDM), Solid Ground Curing (SGC), and Ink Jet printing techniques.

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Why Rapid Prototyping?

The reasons of Rapid Prototyping are

• To increase effective communication.
• To decrease development time.
• To decrease costly mistakes.
• To minimize sustaining engineering changes.
• To extend product lifetime by adding necessary features and eliminating redundant features early in the design.

Rapid Prototyping decreases development time by allowing corrections to a product to be made early in the process. By giving engineering, manufacturing, marketing, and purchasing a look at the product early in the design process, mistakes can be corrected and changes can be made while they are still inexpensive. The trends in manufacturing industries continue to emphasize the following:

• Increasing number of variants of products.
• Increasing product complexity.
• Decreasing product lifetime before obsolescence.
• Decreasing delivery time.

Rapid Prototyping improves product development by enabling better communication in a concurrent engineering environment.

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Methodology of Rapid Prototyping

The basic methodology for all current rapid prototyping techniques can be summarized as follows:

1. A CAD model is constructed, then converted to STL format. The resolution can be set to minimize stair stepping.
2. The RP machine processes the .STL file by creating sliced layers of the model.
3. The first layer of the physical model is created. The model is then lowered by the thickness of the next layer, and the process is repeated until completion of the model.
4. The model and any supports are removed. The surface of the model is then finished and cleaned.

surface treatments

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The processes of surface treatments, more formally surface engineering, tailor the surfaces of engineering materials to

control friction and wear,

improve corrosion resistance,

change physical property, e.g., conductivity, resistivity, and reflection,

alter dimension,

vary appearance, e.g., color and roughness,

reduce cost.
Ultimately, the functions and/or service lives of the materials can be improved.

Common surface treatments can be divided into two major categories: treatments that cover the surfaces and treatments that alter the surfaces.

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Treatments Covering Surfaces

Organic Coatings: The organic coatings apply paints, cements, laminates, fused powders, lubricants, or floor toppings on the surfaces of materials.

Inorganic Coatings: The inorganic coatings perform electroplatings, autocatalytic platings (electroless platings), conversion coatings, thermal sprayings, hot dippings, hardfacings, furnace fusings, or coat thin films, glass, ceramics on the surfaces of the materials.

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Treatments Altering Surfaces

Hardenings: Selective hardenings can be done by flame, induction, laser or electron beam.

High Energy Treatments: Common high energy treatments include ion implantation, laser glazing/fusion, and electron beam treatment.

Thin Diffusion Treatments: Thin diffusion processes include Ferritic-nitrocarb, boronizing, and other high temperature reaction processes, e.g., TiC, VC.

Heavy Diffusion Treatments: Heavy diffusion processes include carburizing, nitriding, and carbonitriding.

Special Treatments: Some special treatments, such as cryo, magnetic, and sonic treatments, affect not only the surfaces but also the bulk materials.

Burnishing

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Burnishing is a process by which a smooth hard tool (using sufficient pressure) is rubbed on the metal surface. This process flattens the high spots by causing plastic flow of the metal.The edges of sheet metal can be smoothed out by pushing the sheet metal through a die that will exert a compressive force to smooth out the blanked edge and the burrs caused by the die break.

Roller Burnishing improves the finish and size of surfaces of revolution such as cylinders and conical surfaces. Both internal and external surfaces can be burnished using an appropriate tool.

Burnishing improves the surface finish, surface hardness, wear-resistance, fatigue and corrosion resistance.

Machining: An Introduction

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In terms of annual dollars spent, machining is the most important of the manufacturing processes. Machining can be defined as the process of removing material from a workpiece in the form of chips. The term metal cutting is used when the material is metallic. Most machining has very low set-up cost compared to forming, molding, and casting processes. However, machining is much more expensive for high volumes. Machining is necessary where tight tolerances on dimensions and finishes are required.

The Machining section is divided into the following categories:
DRILLING:

TURNING:

MILLING:

GRINDING:

CHIP FORMATION:

Hot Forming Centrifugal Casting

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Centrifugal casting as a category includes Centrifugal Casting, Semi-Centrifugal Casting and Centrifuging.
Centrifugal Casting: In centrifugal casting, a permanent mold is rotated about its axis at high speeds (300 to 3000 rpm) as the molten metal is poured. The molten metal is centrifugally thrown towards the inside mold wall, where it solidifies after cooling. The casting is usually a fine grain casting with a very fine-grained outer diameter, which is resistant to atmospheric corrosion, a typical situation with pipes. The inside diameter has more impurities and inclusions, which can be machined away.
Only cylindrical shapes can be produced with this process. Size limits are upto 3 m (10 feet) diameter and 15 m (50 feet) length. Wall thickness can be 2.5 mm to 125 mm (0.1 - 5.0 in). The tolerances that can be held on the OD can be as good as 2.5 mm (0.1 in) and on the ID can be 3.8 mm (0.15 in). The surface finish ranges from 2.5 mm to 12.5 mm (0.1 - 0.5 in) rms.
Typical materials that can be cast with this process are iron, steel, stainless steels, and alloys of aluminum, copper and nickel. Two materials can be cast by introducing a second material during the process. Typical parts made by this process are pipes, boilers, pressure vessels, flywheels, cylinder liners and other parts that are axi-symmetric.
Semi-Centrifugal Casting: The molds used can be permanent or expendable, can be stacked as necessary. The rotational speeds are lower than those used in centrifugal casting. The center axis of the part has inclusion defects as well as porosity and thus is suitable only for parts where this can be machined away. This process is used for making wheels, nozzles and similar parts where the axis of the part is removed by subsequent machining.
Centrifuging: Centrifuging is used for forcing metal from a central axis of the equipment into individual mold cavities that are placed on the circumference. This provides a means of increasing the filling pressure within each mold and allows for reproduction of intricate details. This method is often used for the pouring of investment casting pattern.