Plywood
Description
The Material
Plywood is laminated wood, the layers glued together such that the grain in successive layers are at right angles, giving stiffne
and strength in both directions. The number of layers varies, but is always odd (3, 5, 7…) to give symmetry about the core ply
it is unsymmetric it warps when wet or hot. Those with few plies (3,5) are significantly stronger and stiffer in the direction of
outermost layers; with increasing number of plies the properties become more uniform. High quality plywood is bonded with
synthetic resin. The data listed below describe the in-plane properties of a typical 5-ply.
Composition
Cellulose/Hemicellulose/Lignin/12%H2O/Adhesive
Image
Caption
Plywood dominates the market for both wood and steel stud construction. It is widely used, too, for furniture and fittings, bo
building and packaging.
General properties
Density 43.7 - 49.94 lb/ft^3
Price 0.2565 - 0.4275 USD/lb
Mechanical properties
Young's Modulus 1.001 - 1.885 10^6 psi
Shear Modulus * 0.07252 - 0.2901 10^6 psi
Bulk modulus * 0.2321 - 0.3626 10^6 psi
Poisson's Ratio 0.22 - 0.3
Hardness - Vickers 3- 9 HV
Elastic Limit * 1.305 - 4.351 ksi
Tensile Strength 1.45 - 6.382 ksi
Compressive Strength 1.16 - 3.626 ksi
Elongation 2.4 - 3%
Endurance Limit * 1.015 - 2.321 ksi
Fracture Toughness * 0.91 - 1.638 ksi.in^1/2
Loss Coefficient * 8.00E-03 - 0.11
Thermal properties
Thermal conductor or insulator? Good insulator
Thermal Conductivity 0.1733 - 0.2889 BTU.ft/h.ft^2.F
Thermal Expansion 3.333 - 4.444 µstrain/°F
Specific Heat 0.3965 - 0.4084 BTU/lb.F
Glass Temperature 248 - 284 °F
Maximum Service Temperature * 212 - 266 °F
Minimum Service Temperature * -148 - -94 °F
Electrical properties
Electrical conductor or insulator? Poor insulator
Resistivity 6.00E+13 - 2.00E+14 µohm.cm
Dielectric Constant 6- 8
Power Factor * 0.08 - 0.11
Breakdown Potential * 10.16 - 15.24 V/mil
Optical properties
Transparency Opaque
Eco properties
Production Energy 2708 - 3142 kcal/lb
CO2 creation -0.9 - -0.7 kg/kg
Recycle FALSE
Downcycle TRUE
Biodegrade TRUE
Incinerate TRUE
Landfill TRUE
A renewable resource? TRUE
Impact on the environment
Wood is a renewable resource, absorbing CO2 as it grows. Present day consumption for engineering purposes can readily be
Processability (Scale 1 = impractical to 5 = excellent)
Mouldability 3- 4
Machinability 5
Durability
Flammability Poor
Fresh Water Average
Sea Water Average
Weak Acid Average
Strong Acid Very Poor
Weak Alkalis Good
Strong Alkalis Poor
Organic Solvents Good
UV Good
Oxidation at 500C Very Poor
Supporting information
Design guidelines
Plywoods offers high strength at low weight. Those for general construction are made from softwood plys, but the way in wh
Technical notes
Low cost plywoods are bonded with starch or animal glues and are not water resistant -- they are used for boxes and internal
Typical uses
Furniture, building and construction, marine and boat building, packaging, transport and vehicles, musical instruments, aircra
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e at right angles, giving stiffness
symmetry about the core ply - if
and stiffer in the direction of the
uality plywood is bonded with
, for furniture and fittings, boat
ering purposes can readily be met by controlled planting and harvesting, making wood a truly sustainable material.
wood plys, but the way in which plywood is made allows for great flexibility. For aesthetic purposes, hardwoods can be used for the oute
e used for boxes and internal construction. Waterproof and marine plywoods are bonded with synthetic resin -- they are used for externa
s, musical instruments, aircraft, modeling.
rdwoods can be used for the outermost plys, giving "paneling plywoods" faced with walnut, mahogany or other expensive woods on a cor
c resin -- they are used for external paneling and general construction.
or other expensive woods on a core of softwood. Those for ultra-light design have hardwood outer plys on a core of balsa. Metal-faced ply
on a core of balsa. Metal-faced plywoods can be riveted. Curved moldings for furniture such as chairs are made by laying-up the unbonde
e made by laying-up the unbonded plys in a shaped mould and curing the adhesive under pressure using an airbag or matching mould. Sin
g an airbag or matching mould. Singly curved shapes are straightforward; double curvatures should be minimized or avoided.
inimized or avoided.
Softwood: pine, across grain
Description
The Material
Softwoods come from coniferous, mostly evergreen, trees such as spruce, pine, fir and redwood. Wood must be seasoned be
Composition
Cellulose/Hemicellulose/Lignin/12%H2O
Image
Caption
Wood remains one of the world's major structural materials, as well finding application in more delicate objects like furniture
General properties
Density 27.47 - 37.46 lb/ft^3
Price 0.2565 - 0.6841 USD/lb
Mechanical properties
Young's Modulus 0.08702 - 0.1305 10^6 psi
Shear Modulus* 0.05076 - 0.05802 10^6 psi
Bulk modulus 0.05366 - 0.05947 10^6 psi
*
Poisson's Ratio 0.02 - 0.04
Hardness - Vickers 2.6 - 3.2 HV
Elastic Limit* 0.2466 - 0.3771 ksi
Tensile Strength 0.4641 - 0.5656 ksi
*
Compressive Strength 0.4351 - 1.305 ksi
Elongation 1- 1.5 %
*
Endurance Limit 0.1392 - 0.174 ksi
*
Fracture Toughness 0.364 - 0.455 ksi.in^1/2
*
Loss Coefficient 0.028 - 0.036
Thermal properties
Good insulator
Thermal conductor or insulator?
Thermal Conductivity 0.04622 - 0.08089 BTU.ft/h.ft^2.F
*
Thermal Expansion 14.44 - 20 µstrain/°F
Specific Heat 0.3965 - 0.4084 BTU/lb.F
Glass Temperature 170.6 - 215.6 °F
Maximum Service Temperature - 248 284 °F
*
Minimum Service Temperature - -148 -94 °F
Electrical properties
Poor insulator
Electrical conductor or insulator?
Resistivity * 2.10E+14 - 7.00E+14 µohm.cm
*
Dielectric Constant 5- 6.2
Power Factor * 0.05 - 0.07
Breakdown * Potential 25.4 - 50.8 V/mil
Optical properties
Transparency Opaque
Eco properties
Production Energy 1560 - 1723 kcal/lb
CO2 creation -1.16 - -1.05 kg/kg
Recycle FALSE
Downcycle TRUE
Biodegrade TRUE
Incinerate TRUE
Landfill TRUE
TRUE
A renewable resource?
Impact on the environment
Wood is a renewable resource, absorbing CO2 as it grows. Present day consumption for engineering purposes can readily be
Processability (Scale 1 = impractical to 5 = excellent)
Mouldability 2- 3
Machinability 5
Durability
FlammabilityPoor
A
Fresh Water verage
Sea Water Average
Weak Acid Average
Strong AcidVery Poor
G
Weak Alkalis ood
Poor
Strong Alkalis
Good
Organic Solvents
UV Good
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
Wood offers a remarkable combination of properties. It is light, and, parallel to the grain, it is stiff, strong and tough - as good
Technical notes
The values for the mechanical properties given for woods require explanation. Wood-science laboratories measure the mean
Typical uses
Flooring; furniture; containers; cooperage; sleepers (when treated); building construction; boxes; crates and palettes; planing
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wood. Wood must be seasoned before it is used. Seasoning is the process of drying the natural moisture out of the raw timber to make it
more delicate objects like furniture and musical instruments.
gineering purposes can readily be met by controlled planting and harvesting, making wood a truly sustainable material.
is stiff, strong and tough - as good, per unit weight, as any man-made material except CFRP. It is cheap, it is renewable, and the fossil-fuel
e laboratories measure the mean properties of high-quality "clear" wood samples: small specimens with no knots or other defects; the d
boxes; crates and palettes; planing-mill products; sub-flooring; sheathing and as the feedstock for plywood, particleboard and hardboard.
out of the raw timber to make it dimensionally stable, allowing its use without shrinking or warping. In air-seasoning the wood is dried na
nable material.
it is renewable, and the fossil-fuel energy needed to cultivate and harvest it is outweighed by the energy it captures from the sun during g
h no knots or other defects; the data for woods in the Level 3 CES database is of this type. This is not, however, the data needed for desig
od, particleboard and hardboard.
air-seasoning the wood is dried naturally in covered but open-sided structure. In kiln-drying the wood is artificially dried in an oven or kiln
y it captures from the sun during growth. It is easily machined, carved and joined, and - when laminated - it can be molded to complex sha
owever, the data needed for design. All engineering materials have some variability in quality and properties. To allow for this design hand
artificially dried in an oven or kiln. Modern kilns are so designed that an accurate control of moisture is achieved. Wood has been used fo
- it can be molded to complex shapes. And it is aesthetically pleasing, warm both in color and feel, and with associations of craftsmanship
rties. To allow for this design handbooks list "allowables" - property values that will be met or exceeded by, say, 99% of all samples (mean
achieved. Wood has been used for construction and to make products since the earliest recorded time. The ancient Egyptians used it for
with associations of craftsmanship and quality.
by, say, 99% of all samples (meaning the mean value minus 2.33 standard deviations). Natural materials like wood show greater variabilit
The ancient Egyptians used it for furniture, sculpture and coffins before 2500 BC. The Greeks at the peak of their empire (700 BC) and the
s like wood show greater variability than man-made materials like steel, with the result that the allowable values for mechanical propertie
k of their empire (700 BC) and the Romans at the peak of theirs (around 0 AD) made elaborate buildings, bridges, boats, chariots and wea
le values for mechanical properties may be only 50% of the mean. There is a second problem: structures made of wood are much larger t
, bridges, boats, chariots and weapons of wood, and established the craft of furniture making that is still with us today. More diversity of
s made of wood are much larger than the wood-science test samples. They contain knots, shakes and sloping grain, all of which degrade p
l with us today. More diversity of use appeared in Mediaeval times, with the use of wood for large-s
oping grain, all of which degrade properties. To deal with this the wood is "stress-graded" by visual inspecti
Softwood: pine, along grain
Description
The Material
Softwoods come from coniferous, mostly evergreen, trees such as spruce, pine, fir and redwood. Wood must be seasoned be
Composition
Cellulose/Hemicellulose/Lignin/12%H2O
Image
Caption
Wood remains one of the world's major structural materials, as well finding application in more delicate objects like furniture
General properties
Density 27.47 - 37.46 lb/ft^3
Price 0.2565 - 0.6841 USD/lb
Mechanical properties
Young's Modulus 1.218 - 1.494 10^6 psi
Shear Modulus* 0.08992 - 0.1102 10^6 psi
Bulk modulus 0.05366 - 0.05947 10^6 psi
*
Poisson's Ratio 0.35 - 0.4
*
Hardness - Vickers 3- 4 HV
Elastic Limit* 5.076 - 6.527 ksi
*
Tensile Strength 8.702 - 14.5 ksi
*
Compressive Strength 5.076 - 6.237 ksi
Elongation * 1.99 - 2.43 %
*
Endurance Limit 2.756 - 3.336 ksi
*
Fracture Toughness 3.094 - 3.731 ksi.in^1/2
*
Loss Coefficient 7.00E-03 - 0.01
Thermal properties
Good insulator
Thermal conductor or insulator?
*
Thermal Conductivity 0.1271 - 0.1733 BTU.ft/h.ft^2.F
*
Thermal Expansion 1.389 - 5 µstrain/°F
Specific Heat 0.3965 - 0.4084 BTU/lb.F
Glass Temperature 170.6 - 215.6 °F
Maximum Service Temperature - 248 284 °F
*
Minimum Service Temperature - -148 338 °F
Electrical properties
Poor insulator
Electrical conductor or insulator?
Resistivity * 6.00E+13 - 2.00E+14 µohm.cm
*
Dielectric Constant 5- 6.2
Power Factor * 0.05 - 0.1
Breakdown * Potential 10.16 - 15.24 V/mil
Optical properties
Transparency Opaque
Eco properties
Production Energy 1560 - 1723 kcal/lb
CO2 creation -1.16 - -1.05 kg/kg
Recycle FALSE
Downcycle TRUE
Biodegrade TRUE
Incinerate TRUE
Landfill TRUE
TRUE
A renewable resource?
Impact on the environment
Wood is a renewable resource, absorbing CO2 as it grows. Present day consumption for engineering purposes can readily be
Processability (Scale 1 = impractical to 5 = excellent)
Mouldability 2- 3
Machinability 5
Durability
FlammabilityPoor
A
Fresh Water verage
Sea Water Average
Weak Acid Average
Strong AcidVery Poor
G
Weak Alkalis ood
Poor
Strong Alkalis
Good
Organic Solvents
UV Good
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
Wood offers a remarkable combination of properties. It is light, and, parallel to the grain, it is stiff, strong and tough - as good
Technical notes
The values for the mechanical properties given for woods require explanation. Wood-science laboratories measure the mean
Typical uses
Flooring; furniture; containers; cooperage; sleepers (when treated); building construction; boxes; crates and palettes; planing
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Reference
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Producers
wood. Wood must be seasoned before it is used. Seasoning is the process of drying the natural moisture out of the raw timber to make it
more delicate objects like furniture and musical instruments.
gineering purposes can readily be met by controlled planting and harvesting, making wood a truly sustainable material.
is stiff, strong and tough - as good, per unit weight, as any man-made material except CFRP. It is cheap, it is renewable, and the fossil-fuel
e laboratories measure the mean properties of high-quality "clear" wood samples: small specimens with no knots or other defects; the d
boxes; crates and palettes; planing-mill products; sub-flooring; sheathing and as the feedstock for plywood, particleboard and hardboard.
out of the raw timber to make it dimensionally stable, allowing its use without shrinking or warping. In air-seasoning the wood is dried na
nable material.
it is renewable, and the fossil-fuel energy needed to cultivate and harvest it is outweighed by the energy it captures from the sun during g
h no knots or other defects; the data for woods in the Level 3 CES database is of this type. This is not, however, the data needed for desig
od, particleboard and hardboard.
air-seasoning the wood is dried naturally in covered but open-sided structure. In kiln-drying the wood is artificially dried in an oven or kiln
y it captures from the sun during growth. It is easily machined, carved and joined, and - when laminated - it can be molded to complex sha
owever, the data needed for design. All engineering materials have some variability in quality and properties. To allow for this design hand
artificially dried in an oven or kiln. Modern kilns are so designed that an accurate control of moisture is achieved. Wood has been used fo
- it can be molded to complex shapes. And it is aesthetically pleasing, warm both in color and feel, and with associations of craftsmanship
rties. To allow for this design handbooks list "allowables" - property values that will be met or exceeded by, say, 99% of all samples (mean
achieved. Wood has been used for construction and to make products since the earliest recorded time. The ancient Egyptians used it for
with associations of craftsmanship and quality.
by, say, 99% of all samples (meaning the mean value minus 2.33 standard deviations). Natural materials like wood show greater variabilit
The ancient Egyptians used it for furniture, sculpture and coffins before 2500 BC. The Greeks at the peak of their empire (700 BC) and the
s like wood show greater variability than man-made materials like steel, with the result that the allowable values for mechanical propertie
k of their empire (700 BC) and the Romans at the peak of theirs (around 0 AD) made elaborate buildings, bridges, boats, chariots and wea
le values for mechanical properties may be only 50% of the mean. There is a second problem: structures made of wood are much larger t
, bridges, boats, chariots and weapons of wood, and established the craft of furniture making that is still with us today. More diversity of
s made of wood are much larger than the wood-science test samples. They contain knots, shakes and sloping grain, all of which degrade p
l with us today. More diversity of use appeared in Mediaeval times, with the use of wood for large-s
oping grain, all of which degrade properties. To deal with this the wood is "stress-graded" by visual inspecti
Flexible Polymer Foam (LD)
Description
The Material
Polymer foams are made by the controlled expansion and solidification of a liquid or melt through a blowing agent; physical,
Composition
Hydrocarbon
Image
Caption
Flexible latex foams are used for cushions, mattresses and packaging.
General properties
Density 2.372 - 4.37 lb/ft^3
Price 0.5985 - 4.874 USD/lb
Mechanical properties
Young's Modulus 1.45E-04 - 4.35E-04 10^6 psi
Shear Modulus 5.80E-05 - 2.90E-04 10^6 psi
Bulk modulus 1.45E-04 - 4.35E-04 10^6 psi
Poisson's Ratio 0.23 - 0.33
Hardness - Vickers 2.00E-03 - 0.03 HV
Elastic Limit 2.90E-03 - 0.04351 ksi
Tensile Strength 0.03481 - 0.3408 ksi
Compressive Strength 2.90E-03 - 0.04351 ksi
Elongation 10 - 175 %
*
Endurance Limit 0.02901 - 0.2901 ksi
*
Fracture Toughness 0.01365 - 0.0455 ksi.in^1/2
*
Loss Coefficient 0.1 - 0.5
Thermal properties
Good insulator
Thermal conductor or insulator?
Thermal Conductivity 0.02311 - 0.03409 BTU.ft/h.ft^2.F
Thermal Expansion 63.89 - 122.2 µstrain/°F
Specific Heat 0.418 - 0.5398 BTU/lb.F
Melting Point 233.3 - 350.3 °F
Glass Temperature -171.7 - 8.33 °F
Maximum Service Temperature - 181.1 233.3 °F
Minimum Service Temperature --99.67 -9.67 °F
Electrical properties
Good insulator
Electrical conductor or insulator?
Resistivity 1.00E+20 - 1.00E+23 µohm.cm
Dielectric Constant 1.05 - 1.3
Power Factor 1.00E-04 - 6.00E-04
Breakdown Potential 101.6 - 177.8 V/mil
Optical properties
Transparency Opaque
Eco properties
Production * Energy 1.22E+04 - 1.35E+04 kcal/lb
CO2 creation * 4.78 - 5.28 kg/kg
Recycle FALSE
Downcycle TRUE
Biodegrade FALSE
Incinerate TRUE
Landfill TRUE
FALSE
A renewable resource?
Impact on the environment
Foaming of insulation with CFCs has a damaging effect on the ozone layer - it is now abandoned. Monomers and foaming age
Processability (Scale 1 = impractical to 5 = excellent)
Castability 3- 5
Mouldability 1- 4
Machinability 3- 4
Weldability 1
Durability
FlammabilityVery Poor
V
Fresh Water ery Good
Sea Water Very Good
Weak Acid Very Good
Strong AcidGood
V
Weak Alkalis ery Good
Average
Strong Alkalis
Good
Organic Solvents
UV Average
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
Flexible foams have characteristics that suit them for cushioning and packaging of delicate objects. They are shaped by injecti
Technical notes
The properties of foams depend, most directly, on the material of which they are made and on the relative density (the fracti
Typical uses
Packaging, buoyancy, cushioning, sleeping mats, soft furnishings, artificial skin, sponges, carriers for inks and dyes.
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hrough a blowing agent; physical, chemical or mechanical blowing agents are possible. The resulting cellular material has a lower density,
oned. Monomers and foaming agents pose hazards; good practice overcomes these. For cushioning, the requirements are comfort and lon
objects. They are shaped by injecting or pouring a mix of polymer, catalyst and foaming agent into a mould where the agent evolves gas, e
on the relative density (the fraction of the foam that is solid). Most commercial foams have a relative density between 1% and 30%. To a
riers for inks and dyes.
ular material has a lower density, stiffness and strength than the parent material, by an amount that depends on its relative density - the
requirements are comfort and long life; polyurethane foams have been commonly used, but concerns about flammability and durability l
uld where the agent evolves gas, expanding the foam. Expanding in a cold mould gives a solid surface skin. Closed cell foams float in water
ensity between 1% and 30%. To a lesser extent, the properties depend on the size and the shape of the cells. Low density, closed cell, foa
pends on its relative density - the volume-fraction of solid in the foam. Flexible foams can be soft and compliant, the material of cushions
bout flammability and durability limit their use in furniture.
n. Closed cell foams float in water; open cell foams absorb liquids and act as sponges.
cells. Low density, closed cell, foams have exceptional low thermal conductivity. Skinned rigid foams have good bending stiffness and stre
mpliant, the material of cushions, mattresses, and padded clothing. Most are made from polyurethane, although latex (natural rubber) an
ve good bending stiffness and strength of low weight.
although latex (natural rubber) and most other elastomers can be foamed.
Rigid Polymer Foam (LD)
Description
The Material
Polymer foams are made by the controlled expansion and solidification of a liquid or melt through a blowing agent; physical,
Composition
Hydrocarbon
Image
Caption
Rigid polymer foam is used as the core of the GFRP sandwich shell for ultra-light weight designs such as this glider.
General properties
Density 2.247 - 4.37 lb/ft^3
Price 1.026 - 51.3 USD/lb
Mechanical properties
Young's Modulus 3.34E-03 - 0.0116 10^6 psi
Shear Modulus 1.16E-03 - 5.08E-03 10^6 psi
Bulk modulus 3.34E-03 - 0.0116 10^6 psi
Poisson's Ratio 0.25 - 0.33
Hardness - Vickers 0.037 - 0.17 HV
Elastic Limit 0.04351 - 0.2466 ksi
Tensile Strength 0.06527 - 0.3263 ksi
Compressive Strength 0.05366 - 0.2466 ksi
Elongation 2- 5%
*
Endurance Limit 0.04293 - 0.1973 ksi
Fracture Toughness 1.91E-03 - 0.0182 ksi.in^1/2
*
Loss Coefficient 5.00E-03 - 0.3
Thermal properties
Good insulator
Thermal conductor or insulator?
Thermal Conductivity 0.01329 - 0.02311 BTU.ft/h.ft^2.F
Thermal Expansion 11.11 - 44.44 µstrain/°F
Specific Heat 0.2675 - 0.4562 BTU/lb.F
Glass Temperature 152.3 - 339.5 °F
Maximum Service Temperature - 152.3 296.3 °F
Minimum Service Temperature --351.7 -99.67 °F
Electrical properties
Good insulator
Electrical conductor or insulator?
Resistivity 1.00E+17 - 1.00E+21 µohm.cm
Dielectric Constant 1.04 - 1.448
Power Factor 8.00E-05 - 5.10E-03
Breakdown Potential 48.26 - 153.4 V/mil
Optical properties
Transparency Opaque
Eco properties
Production * Energy 1.50E+04 - 1.66E+04 kcal/lb
CO2 creation * 6.59 - 7.28 kg/kg
Recycle TRUE
Downcycle TRUE
Biodegrade FALSE
Incinerate TRUE
Landfill TRUE
FALSE
A renewable resource?
Impact on the environment
Foaming of insulation with CFCs has a damaging effect on the ozone layer - it is now abandoned. Monomers and foaming age
Processability (Scale 1 = impractical to 5 = excellent)
Castability 1- 3
Mouldability 3- 4
Machinability 3- 4
Weldability 1- 2
Durability
FlammabilityAverage
V
Fresh Water ery Good
Sea Water Very Good
Weak Acid Very Good
Strong AcidAverage
V
Weak Alkalis ery Good
Good
Strong Alkalis
Good
Organic Solvents
UV Good
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
Energy management and packaging requires the ability to absorb energy at a constant, controlled crushing stress; here polyu
Technical notes
The properties of foams depend, most directly, on the material of which they are made and on the relative density (the fracti
Typical uses
Thermal insulation, Cores for sandwich structures, Panels, Partitions, Refrigeration, Energy Absorption, Packaging, Buoyancy,
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hrough a blowing agent; physical, chemical or mechanical blowing agents are possible. The resulting cellular material has a lower density,
igns such as this glider.
oned. Monomers and foaming agents pose hazards; good practice overcomes these.
rolled crushing stress; here polyurethane, polypropylene and polystyrene foams are used. Acoustic control requires the ability to absorb
on the relative density (the fraction of the foam that is solid). Most commercial foams have a relative density between 1% and 30%. To a
Absorption, Packaging, Buoyancy, Floatation.
ular material has a lower density, stiffness and strength than the parent material, by an amount that depends on its relative density - the
trol requires the ability to absorb sound and damp vibration; polyurethane, polystyrene and polyethylene foams are all used. Thermal ins
ensity between 1% and 30%. To a lesser extent, the properties depend on the size and the shape of the cells. Low density, closed cell, foa
pends on its relative density - the volume-fraction of solid in the foam. Rigid foams are made from polystyrene, phenolic, polyethylene, po
ne foams are all used. Thermal insulation requires long life; polyurethane foams were common but are now replaced by phenolics and pol
cells. Low density, closed cell, foams have exceptional low thermal conductivity. Skinned rigid foams have good bending stiffness and stre
tyrene, phenolic, polyethylene, polypropylene or derivatives of polymethylmethacrylate. They are light and stiff, and have mechanical pro
ow replaced by phenolics and polystyrenes. When fire-protection is needed phenolic foams are used. Foams are usually shaped by injecti
ve good bending stiffness and strength of low weight.
and stiff, and have mechanical properties the make them attractive for energy management and packaging, and for lightweight structura
oams are usually shaped by injecting or pouring a mix of polymer and foaming agent into a mould where the agent evolves gas, expanding
ging, and for lightweight structural use. Open-cell foams can be used as filters, closed cell foams as flotation. Self-skinning foams, called 'st
e the agent evolves gas, expanding the foam. The mix can be pelletised, and the mould part-filled with solid pellets before foaming (see "E
ion. Self-skinning foams, called 'structural' or 'syntactic', have a dense surface skin made by foaming in a cold mould. Rigid polymer foams
olid pellets before foaming (see "Expanded foam molding" in this database). Expanding in a cold mould gives a solid surface skin, creating
a cold mould. Rigid polymer foams are widely used as cores of sandwich panels.
gives a solid surface skin, creating a sandwich-like structure with attractive mechanical properties.
Aluminium alloys
Description
The Material
Aluminum was once so rare and precious that the Emperor Napoleon III of France had a set of cutlery made from it that cost
Composition
Al + alloying elements, e.g. Mg, Mn, Cr, Cu, Zn, Zr, Li
Image
Caption
Aluminum can formed both by casting and by deformation.
General properties
Density 156.1 - 181 lb/ft^3
Price 0.6453 - 1.046 USD/lb
Mechanical properties
Young's Modulus 9.863 - 11.89 10^6 psi
Shear Modulus 3.626 - 4.496 10^6 psi
Bulk modulus 9.282 - 10.3 10^6 psi
Poisson's Ratio 0.32 - 0.36
Hardness - Vickers 12 - 150.5 HV
Elastic Limit 4.351 - 72.52 ksi
Tensile Strength 8.412 - 79.77 ksi
Compressive Strength 4.351 - 72.52 ksi
Elongation 1- 44 %
Endurance Limit 3.133 - 22.77 ksi
Fracture Toughness 20.02 - 31.85 ksi.in^1/2
Loss Coefficient 1.00E-04 - 2.00E-03
Thermal properties
Good conductor
Thermal conductor or insulator?
Thermal Conductivity 43.91 - 135.8 BTU.ft/h.ft^2.F
Thermal Expansion 11.67 - 13.33 µstrain/°F
Specific Heat 0.2047 - 0.2365 BTU/lb.F
Melting Point 886.7 - 1250 °F
Maximum Service Temperature - 248 410 °F
Minimum Service Temperature -459.7 °F
Electrical properties
Good conductor
Electrical conductor or insulator?
Resistivity 2.5 - 6.5 µohm.cm
Optical properties
Transparency Opaque
Eco properties
Production Energy 1.99E+04 - 2.20E+04 kcal/lb
CO2 creation 11.6 - 12.8 kg/kg
Recycle TRUE
Downcycle TRUE
Biodegrade FALSE
Incinerate FALSE
Landfill TRUE
FALSE
A renewable resource?
Impact on the environment
Aluminum ore is abundant. It takes a lot of energy to extract aluminum, but it is easily recycled at low energy cost.
Processability (Scale 1 = impractical to 5 = excellent)
Castability 4- 5
Formability 3- 4
Machinability 4- 5
Weldability 3- 4
Solder/Brazability 2- 3
Durability
FlammabilityGood
V
Fresh Water ery Good
Sea Water Good
Weak Acid Very Good
Strong AcidVery Good
G
Weak Alkalis ood
Poor
Strong Alkalis
Very
Organic SolventsGood
UV Very Good
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
Aluminum alloys are light, can be strong, and are easily worked. Pure aluminum has outstanding electrical and thermal condu
Technical notes
Until 1970, designations of wrought aluminum alloys were a mess; in many countries, they were simply numbered in the orde
Typical uses
Aerospace engineering; automotive engineering - pistons, clutch housings, exhaust manifolds; die cast chassis for household
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of cutlery made from it that cost him more than silver. But that was 1860; today, nearly 150 years later, aluminum spoons are things you
led at low energy cost.
nding electrical and thermal conductivity (copper is the only competition here) and is relatively cheap - though still more than twice the pr
were simply numbered in the order of their development. The International Alloy Designation System (IADS), now widely accepted, gives
ds; die cast chassis for household and electronic products; siding for buildings; foil for containers and packaging; beverage cans; electrical
, aluminum spoons are things you throw away - a testament to our ability to be both technically creative and wasteful. Aluminum, the firs
hough still more than twice the price of steel. It is a reactive metal - in powder form it can explode - but in bulk an oxide film (Al2O3) form
ADS), now widely accepted, gives each wrought alloy a 4-digit number. The first digit indicates the major alloying element or elements. Th
ckaging; beverage cans; electrical and thermal conductors.
e and wasteful. Aluminum, the first of the 'light alloys' (with magnesium and titanium), is the third most abundant metal in the earth's cru
in bulk an oxide film (Al2O3) forms on its surface, protecting it from corrosion in water and acids (but not strong alkalis). Aluminum alloys
r alloying element or elements. Thus the series 1xxx describe unalloyed aluminum; the 2xxx series contain copper as the major alloying el
abundant metal in the earth's crust (after iron and silicon) but extracting it costs much energy. It has grown to be the second most import
ot strong alkalis). Aluminum alloys are not good for sliding surfaces - they scuff - and the fatigue strength of the high-strength alloys is poo
in copper as the major alloying element, and so forth. The third and fourth digits are significant in the 1xxx series but not in the others; in
own to be the second most important metal in the economy (steel comes first), and the mainstay of the aerospace industry.
h of the high-strength alloys is poor. Nearly pure aluminum (1000 series alloys) is used for small appliances and siding; high strength alloys
xxx series but not in the others; in 1xxx series they describe the minimum purity of the aluminum; thus 1145 has a minimum purity of 99.4
aerospace industry.
es and siding; high strength alloys are used in aerospace (2000 and 7000 series), and extrudable, medium strength alloys are used in the a
1145 has a minimum purity of 99.45%; 1200 has a minimum purity of 99.00%. In all other series, the third and fourth digits are simply seri
m strength alloys are used in the automotive and general engineering sectors (6000 series).
d and fourth digits are simply serial numbers; thus 5082 and 5083 are two distinct aluminum-magnesium alloys. The second digit has a cu
m alloys. The second digit has a curious function: it indicates a close relationship: thus 5352 is closely related to 5052 and 5252; and 7075
ated to 5052 and 5252; and 7075 and 7475 differ only slightly in composition. To these serial numbers a
Polyamides (Nylons, PA)
Description
The Material
Back in 1945, the war in Europe just ended, the two most prized luxuries were cigarettes and nylons. Nylon (PA) can be drawn
Composition
(NH(CH2)5C0)n
Image
Caption
Polyamides are tough, and easily colored.
General properties
Density 69.92 - 71.17 lb/ft^3
Price 1.645 - 1.81 USD/lb
Mechanical properties
Young's Modulus 0.38 - 0.4641 10^6 psi
Shear Modulus* 0.1407 - 0.1719 10^6 psi
Bulk modulus 0.5366 - 0.5656 10^6 psi
Poisson's Ratio 0.34 - 0.36
Hardness - Vickers 25.8 - 28.4 HV
Elastic Limit 7.252 - 13.75 ksi
Tensile Strength 13.05 - 23.93 ksi
Compressive Strength 7.977 - 15.12 ksi
Elongation 30 - 100 %
*
Endurance Limit 5.221 - 9.572 ksi
*
Fracture Toughness 2.019 - 5.111 ksi.in^1/2
*
Loss Coefficient 0.0125 - 0.01527
Thermal properties
Good insulator
Thermal conductor or insulator?
Thermal Conductivity 0.1346 - 0.1462 BTU.ft/h.ft^2.F
Thermal Expansion 80 - 83 µstrain/°F
Specific Heat* 0.3823 - 0.3976 BTU/lb.F
Melting Point 409.7 - 427.7 °F
Glass Temperature 110.9 - 132.5 °F
Maximum Service Temperature -163.1 188.3 °F
* -189.7
Minimum Service Temperature - -99.67 °F
Electrical properties
Good insulator
Electrical conductor or insulator?
Resistivity * 1.50E+19 - 1.40E+20 µohm.cm
Dielectric Constant 3.7 - 3.9
Power Factor * 0.014 - 0.06
Breakdown Potential 383.5 - 416.6 V/mil
Optical properties
Transparency Translucent
Refractive Index 1.52 - 1.53
Eco properties
Production * Energy 1.11E+04 - 1.22E+04 kcal/lb
CO2 creation 3.99 - 4.41 kg/kg
Recycle TRUE
Downcycle TRUE
Biodegrade FALSE
Incinerate TRUE
Landfill TRUE
FALSE
A renewable resource?
Recycle mark
Impact on the environment
Nylons have no known toxic effects, although they are not entirely inert biologically. Nylons are oil-derivatives, but this will n
Processability (Scale 1 = impractical to 5 = excellent)
Castability 1- 2
Mouldability 4- 5
Machinability 3- 4
Weldability 5
Durability
FlammabilityAverage
V
Fresh Water ery Good
Sea Water Very Good
Weak Acid Good
Strong AcidPoor
V
Weak Alkalis ery Good
Good
Strong Alkalis
Average
Organic Solvents
UV Average
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
Nylons are tough, strong and have a low coefficient of friction, with useful properties over a wide range of temperature (-80 t
Technical notes
The density, stiffness, strength, ductility and toughness of Nylons all lie near the average for unreinforced polymers. Their the
Typical uses
Light duty gears, bushings, sprockets and bearings; electrical equipment housings, lenses, containers, tanks, tubing, furniture
Tradenames
Adell, Akulon, Albis, Amilan, Ashlene, Capron, Celanese, Chemlon, Durethan, Gapex, Grilon, Grivory, Hylon, Kopa, Latamid, Lu
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d nylons. Nylon (PA) can be drawn to fibers as fine as silk, and was widely used as a substitute for it. Today, newer fibers have eroded its d
are oil-derivatives, but this will not disadvantage them in the near future. With refinements in polyolefin catalysis, nylons face stiff comp
a wide range of temperature (-80 to +120 C). They are easy to injection mould, machine and finish, can be thermally or ultrasonically bond
r unreinforced polymers. Their thermal conductivities and thermal expansion are a little lower than average. Reinforcement with mineral,
ontainers, tanks, tubing, furniture casters, plumbing connections, bicycle wheel covers, ketchup bottles, chairs, toothbrush bristles, handle
Grivory, Hylon, Kopa, Latamid, Lubrilon, Magnacomp, Maranyl, Minlon, NSC, Nivionplast, Novamid, Nydur, Nylamid, Nylene, Nypel, Orgam
day, newer fibers have eroded its dominance in garment design, but nylon-fiber ropes, and nylon as reinforcement for rubber (in car tires)
n catalysis, nylons face stiff competition from less expensive polymers.
e thermally or ultrasonically bonded, or joined with epoxy, phenol-formaldehyde or polyester adhesives. Certain grades of nylon can be e
age. Reinforcement with mineral, glass powder or glass fiber increases the modulus, strength and density. Semi-crystalline nylon is disting
chairs, toothbrush bristles, handles, bearings, food packaging. Nylons are used as hot-melt adhesives for book bindings; as fibers - ropes,
dur, Nylamid, Nylene, Nypel, Orgamide, Radilon, Schulamid, Selar, Sniamid, Star-C, Star-L, Staramide, Texalon, Ultramid, Vestamid, Wellam
forcement for rubber (in car tires) and other polymers (PTFE, for roofs) remains important. It is used in product design for tough casings, f
s. Certain grades of nylon can be electroplated allowing metallisation, and most accept print well. A blend of PPO/Nylon is used in fenders
ty. Semi-crystalline nylon is distinguished by a numeric code for the material class indicating the number of carbon atoms between two ni
r book bindings; as fibers - ropes, fishing line, carpeting, car upholstery and stockings; as aramid fibers - cables, ropes, protective clothing,
alon, Ultramid, Vestamid, Wellamid, Zytel
product design for tough casings, frames and handles, and - reinforced with glass - as bearings gears and other load-bearing parts. There a
nd of PPO/Nylon is used in fenders, exterior body parts. Nylon fibers are strong, tough, elastic and glossy, easily spun into yarns or blended
r of carbon atoms between two nitrogen atoms in the molecular chain. The amorphous material is transparent; the semi-crystalline mater
cables, ropes, protective clothing, air filtration bags and electrical insulation.
other load-bearing parts. There are many grades (Nylon 6, Nylon 66, Nylon 11….) each with slightly different properties.
, easily spun into yarns or blended with other materials. Nylons absorb up to 4% water; to prevent dimensional changes, they must be co
parent; the semi-crystalline material is opal white.
erent properties.
ensional changes, they must be conditioned before molding, allowing them to establishing equilibrium with normal atmospheric humidity
ith normal atmospheric humidity. Nylons have poor resistance to strong acids, oxidizing agents and solvents, particularly in transparent g
ents, particularly in transparent grades.
Polyoxymethylene (Acetal, POM)
Description
The Material
POM was first marketed by DuPont in 1959 as Delrin. It is similar to nylon but is stiffer, and has better fatigue and water resis
Composition
(CH2-O)n
Image
General properties
Density 86.77 - 89.27 lb/ft^3
Price 1.599 - 2.394 USD/lb
Mechanical properties
Young's Modulus 0.3626 - 0.7252 10^6 psi
Shear Modulus 0.1218 - 0.3296 10^6 psi
Bulk modulus 0.6382 - 0.6672 10^6 psi
Poisson's Ratio 0.33 - 0.4066
Hardness - Vickers 14.6 - 24.8 HV
Elastic Limit 7.049 - 10.5 ksi
Tensile Strength 8.702 - 13 ksi
Compressive Strength 10.86 - 17.98 ksi
Elongation 10 - 75 %
*
Endurance Limit 3.18 - 4.965 ksi
Fracture Toughness 1.555 - 3.822 ksi.in^1/2
*
Loss Coefficient 6.38E-03 - 0.01702
Thermal properties
Good insulator
Thermal conductor or insulator?
Thermal Conductivity 0.1277 - 0.2025 BTU.ft/h.ft^2.F
Thermal Expansion 42.05 - 112 µstrain/°F
Specific Heat 0.3258 - 0.3422 BTU/lb.F
Melting Point 319.7 - 362.9 °F
Glass Temperature -0.6704 - 17.33 °F
Maximum Service Temperature 170.3 - 206.3 °F
Minimum Service Temperature -189.7 - -99.67 °F
Electrical properties
Good insulator
Electrical conductor or insulator?
Resistivity 3.30E+20 - 3.00E+21 µohm.cm
Dielectric Constant 3.6 - 4
Power Factor 9.50E-04 - 5.00E-03
Breakdown Potential 383.5 - 520.7 V/mil
Optical properties
Transparency Opaque
Eco properties
Production * Energy 1.08E+04 - 1.19E+04 kcal/lb
CO2 creation * 3.8 - 4.2 kg/kg
Recycle TRUE
Downcycle TRUE
Biodegrade FALSE
Incinerate TRUE
Landfill TRUE
FALSE
A renewable resource?
Recycle mark
Impact on the environment
Acetal, like most thermoplastics, is an oil derivative, but this poses no immediate threat to its use.
Processability (Scale 1 = impractical to 5 = excellent)
Castability 1- 2
Mouldability 4- 5
Machinability 3- 4
Weldability 4- 5
Durability
Flammability Poor
V
Fresh Water ery Good
Sea Water Very Good
Weak Acid Good
Strong AcidPoor
G
Weak Alkalis ood
Good
Strong Alkalis
Good
Organic Solvents
UV Average
Very Poor
Oxidation at 500C
Supporting information
Design guidelines
POM is easy to mould by blow molding, injection molding or sheet molding, but shrinkage on cooling limits the minimum reco
Technical notes
The repeating unit of POM is - (CH2O)n and the resulting molecule is linear and highly crystalline. Consequently, POM is easily
Typical uses
POM is more expensive than commodity polymers such as PE, so is limited to high performance applications in which its natu
Tradenames
Acetron, Delrin, Fulton, Latan, Lupital, Plaslube, Tenac, Thermocomp, Ultraform
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has better fatigue and water resistance - nylons, however, have better impact and abrasion resistance. It is rarely used without modificat
n cooling limits the minimum recommended wall thickness for injection molding to 0.1mm. As manufactured, POM is gray but it can be c
alline. Consequently, POM is easily moldable, has good fatigue resistance and stiffness, and is water resistant. In its pure form, POM degra
ance applications in which its natural lubricity is exploited. It is found in fuel-system; seat-belt components; steering columns; window-sup
t is rarely used without modifications: most often filled with glass fiber, flame retardant additives or blended with PTFE or PU. The last, PO
tured, POM is gray but it can be colored. It can be extruded to produce shapes of constant cross section such as fibers and pipes. The high
stant. In its pure form, POM degrades easily by dePolymerization from the ends of the polymer chain by a process called 'unzipping'. The a
nts; steering columns; window-support brackets and handles; shower heads, ballcocks, faucet cartridges, and various fittings; quality toys;
nded with PTFE or PU. The last, POM/PU blend, has good toughness. POM is used where requirements for good moldability, fatigue resis
such as fibers and pipes. The high crystallinity leads to increased shrinkage upon cooling. It must be processed in the temperature range
a process called 'unzipping'. The addition of 'blocking groups' at the ends of the polymer chains or coPolymerization with cyclic ethers su
, and various fittings; quality toys; garden sprayers; stereo cassette parts; butane lighter bodies; zippers; telephone components; coupling
for good moldability, fatigue resistance and stiffness justify its high price relative to mass polymers, like polyethylene, which are polymeri
ocessed in the temperature range 190-230 C and may require drying before forming because it is hygroscopic. Joining can be done using u
lymerization with cyclic ethers such as ethylene oxide prevents unzipping and hence degradation.
; telephone components; couplings; pump impellers; conveyor plates; gears; sprockets; springs; gears; cams; bushings; clips; lugs; door ha
polyethylene, which are polymerized from cheaper raw materials using lower energy input.
copic. Joining can be done using ultrasonic welding, but POM's low coefficient of friction requires welding methods that use high energy a
ams; bushings; clips; lugs; door handles; window cranks; housings; seat-belt components; watch gears; conveyor links; aerosols; mechani
ng methods that use high energy and long ultrasonic exposure; adhesive bonding is an alternative. POM is a good electrical insulator. With
conveyor links; aerosols; mechanical pen and pencil parts; milk pumps; coffee spigots; filter housings; food conveyors; cams; gears; TV tun
is a good electrical insulator. Without coPolymerization or the addition of blocking groups, POM degrades easily.
od conveyors; cams; gears; TV tuner arms; automotive underhood components.
Stainless steel
Description
The Material
Stainless steels are alloys of iron with chromium, nickel, and - often - four of five other elements. The alloying transmutes pla
Composition
Fe/<0.25C/16 - 30Cr/3.5 - 37Ni/<10Mn + Si,P,S (+N for 200 series)
Image
Caption
One the left: Siemens toaster in brushed austenitic stainless steel (by Porsche Design). On the right, scissors in ferritic stainles
General properties
Density 474.5 - 505.7 lb/ft^3
Price 1.283 - 5.13 USD/lb
Mechanical properties
Young's Modulus 27.41 - 30.46 10^6 psi
Shear Modulus 10.73 - 12.18 10^6 psi
Bulk modulus 19.44 - 21.9 10^6 psi
Poisson's Ratio 0.265 - 0.275
Hardness - Vickers 130 - 570 HV
Elastic Limit 24.66 - 145 ksi
Tensile Strength 69.62 - 324.9 ksi
Compressive Strength 24.66 - 145 ksi
Elongation 5- 70 %
*
Endurance Limit 25.38 - 109.2 ksi
Fracture Toughness 56.42 - 136.5 ksi.in^1/2
*
Loss Coefficient 2.90E-04 - 1.48E-03
Thermal properties
Poor conductor
Thermal conductor or insulator?
Thermal Conductivity 6.933 - 13.87 BTU.ft/h.ft^2.F
Thermal Expansion 7.222 - 11.11 µstrain/°F
Specific Heat 0.1075 - 0.1266 BTU/lb.F
Melting Point 2507 - 2642 °F
Maximum Service Temperature - 1202 1652 °F
-457.9
Minimum Service Temperature - -456.1 °F
Electrical properties
Good conductor
Electrical conductor or insulator?
Resistivity 64 - 107 µohm.cm
Optical properties
Transparency Opaque
Eco properties
Production * Energy 8364 - 9241 kcal/lb
CO2 creation * 4.86 - 5.37 kg/kg
Recycle TRUE
Downcycle TRUE
Biodegrade FALSE
Incinerate FALSE
Landfill TRUE
FALSE
A renewable resource?
Impact on the environment
Stainless steels are FDA approved -- indeed, they are so inert that they can be implanted in the body, and are widely used in f
Processability (Scale 1 = impractical to 5 = excellent)
Castability 3- 4
Formability 2- 3
Machinability 2- 3
Weldability 5
Solder/Brazability 5
Durability
FlammabilityVery Good
V
Fresh Water ery Good
Sea Water Very Good
Weak Acid Very Good
Strong AcidGood
V
Weak Alkalis ery Good
Very
Strong Alkalis Good
Very
Organic SolventsGood
UV Very Good
Very Good
Oxidation at 500C
Supporting information
Design guidelines
Stainless steel must be used efficiently to justify its higher costs, exploiting its high strength and corrosion resistance. Econom
Technical notes
Stainless steels are classified into four categories: the 200and 300 series austenitic (Fe-Cr-Ni-Mn) alloys, the 400 series ferritic
Typical uses
Railway cars, trucks, trailers, food-processing equipment, sinks, stoves, cooking utensils, cutlery, flatware, architectural meta
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ments. The alloying transmutes plain carbon steel that rusts and is prone to brittleness below room temperature into a material that does
he right, scissors in ferritic stainless steel; it is magnetic, austenitic stainless is not.
the body, and are widely used in food processing equipment. All can be recycled.
and corrosion resistance. Economic design uses thin, rolled gauge, simple sections, concealed welds to eliminate refinishing, and grades t
i-Mn) alloys, the 400 series ferritic (Fe-Cr) alloys, the martensitic (Fe-Cr-C) alloys that also form part of the 400 series, and precipitation ha
lery, flatware, architectural metalwork, laundry equipment, chemical-processing equipment, jet-engine parts, surgical tools, furnace and
erature into a material that does neither. Indeed, most stainless steels resist corrosion in most normal environments, and they remain du
eliminate refinishing, and grades that are suitable to manufacturing (such as free machining grades when machining is necessary). Surface
he 400 series, and precipitation hardening or PH (Fe-Cr-Ni-Cu-Nb) alloys with designations starting with S. Typical of the austenitic grades
parts, surgical tools, furnace and boiler components, oil-burner parts, petroleum-processing equipment, dairy equipment, heat-treating e
environments, and they remain ductile to the lowest of temperatures.
n machining is necessary). Surface finish can be controlled by rolling, polishing or blasting. Stainless steels are selected, first, for their corr
S. Typical of the austenitic grades of stainless steel is the grade 304: 74% iron, 18% chromium and 8 % nickel. Here the chromium protects
, dairy equipment, heat-treating equipment, automotive trim. Structural uses in corrosive environments, e.g. nuclear plants, ships, offsho
ls are selected, first, for their corrosion resistance, second, for their strength and third, for their ease of fabrication. Most stainless steels
ckel. Here the chromium protects by creating a protective Cr2O3 film on all exposed surfaces, and the nickel stabilizes face-centered cubi
s, e.g. nuclear plants, ships, offshore oil installations, underwater cables and pipes.
fabrication. Most stainless steels are difficult to bend, draw and cut, requiring slow cutting speeds and special tool geometry. They are av
ickel stabilizes face-centered cubic austenite, giving ductility and strength both at high and low temperatures; they are non-magnetic (a w
pecial tool geometry. They are available in sheet, strip, plate, bar, wire, tubing and pipe, and can be readily soldered and braised. Welding
atures; they are non-magnetic (a way of identifying them). The combination of austenitic and ferritic structures (the duplex stainless steels
dily soldered and braised. Welding stainless steel is possible but the filler metal must be selected to ensure an equivalent composition to
uctures (the duplex stainless steels) provide considerably slower growth of stress-induced cracks, they can be hot-rolled or cast and are of
ure an equivalent composition to maintain corrosion resistance. The 300 series are the most weldable; the 400 series are less weldable.
an be hot-rolled or cast and are often heat treated as well. Austenitic stainless steel with high molybdenum content and copper has excell
he 400 series are less weldable.
um content and copper has excellent resistance to pitting and corrosion. High nitro