Archive for November, 2012

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Hardness Conversion Table

HardnessConversionTableChart.pdf

Hardness Conversion Table
Brinell Haardness   (BHN) Vickers Hardness (HV) Rockwell Hardness (HRB) Rockwell Hardness (HRC)
86 90
95 100 56.2
105 110 62.3
114 120 66.7
124 130 71.2
133 140 75.0
143 150 78.7
152 160 81.7
162 170 85.0
171 180 87.1
181 190 89.5
190 200 91.5
199 210 93.5
209 220 95.0
219 230 96.7
228 240 98.1
238 250 99.5
242 255 23.1
252 265 24.8
261 275 26.4
266 280 27.1
276 290 28.5
280 295 29.2
295 310 31.0
304 320 32.2
314 330 33.3
323 340 34.4
333 350 35.5
342 360 36.6
352 370 37.7
361 380 38.8
371 390 39.8
380 400 40.8
390 410 41.8
399 420 42.7
409 430 43.6
418 440 44.5
428 450 45.3
437 460 46.1
447 470 46.9
456 480 47.7
466 490 48.4
475 500 49.1
485 510 49.8
494 520 50.5
504 530 51.1
513 540 51.7
523 550 52.3
532 560 53.0
542 570 53.6
551 580 54.1
561 590 54.7
570 600 55.2
580 610 55.7
589 620 56.3
599 630 56.8
608 640 57.3
618 650 57.8

Coefficient of Friction

CoefficientOfFrictionChart.pdf

Coefficient of Friction
Extreme care is needed in using friction coefficients. Please use additional independent references.  For any specific application the ideal method of determining the coefficient of friction is by trials.  A short table is included above the main table to illustrate how the coefficient of friction is affected by surface films.  When a metal surface is perfectly clean in a vacuum, the friction is much higher than the normal accepted value and seizure can easily occur.
Effect of Oxide film, Sulfide film on Coefficient of Static Friction
MATERIAL Clean & Dry Thick Oxide Film Sulfide Film
Steel-Steel 0.78 0.27 0.39
Copper-Copper 1.21 0.76 0.74
Coefficient of Friction
Mat. 1 Mat 2. Dry Greasy
Static Sliding Static Sliding
Aluminum Alluminum 1.05-1.35 1.4 0.3
Aluminum Mild Steel 0.61 0.47
Brake Material Cast Iron 0.4
Brake Material Cast Iron (Wet) 0.2
Brass Cast Iron 0.3
Brick Wood 0.6
Bronze Cast Iron 0.22
Bronze Steel 0.16
Cadmium Cadmium 0.5 0.05
Cadmium Mild Steel 0.46
Cast Iron Cast Iron 1.1 0.15 0.07
Cast Iron Oak 0.49 0.075
Chromium Chromium 0.41 0.34
Copper Cast Iron 1.05 0.29
Copper Copper 1.0 0.08
Copper Mild Steel 0.53 0.36 0.18
Copper-Lead Alloy Steel 0.22
Diamond Diamond 0.1 0.05-0.1
Diamond Metal 0.1-0.15 0.1
Glass Glass 0.9-1.0 0.4 0.1-0.6 0.09-0.12
Glass Metal 0.5-0.7 0.2-0.3
Glass Nickel 0.78 0.56
Graphite Graphite 0.1 0.1
Graphite Steel 0.1 0.1
Graphite (In vacuum) Graphite (In vacuum) 0.5-0.8
Hard Carbon Hard Carbon 0.16 0.12-0.14
Hard Carbon Steel 0.14 0.11-0.14
Iron Iron 1.0 0.15-0.2
Lead Cast Iron 0.43
Leather Wood 0.3-0.4
Leather Metal (Clean) 0.6 0.2
Leather Metal (Wet) 0.4
Leather Oak (Parallel grain) 0.61 0.52
Magnesium Magnesium 0.6 0.08
Nickel Nickel 0.7-1.1 0.53 0.28 0.12
Nickel Mild Steel 0.64 0.178
Nylon Nylon 0.15-0.25
Oak Oak (Parallel grain) 0.62 0.48
Oak Oak (cross grain) 0.54 0.32 0.072
Platinum Platinum 1.2 0.25
Plexiglas Plexiglas 0.8 0.8
Plexiglas Steel 0.4 – 0.5 0.4 – 0.5
Polystyrene Polystyrene 0.5 0.5
Polystyrene Steel 0.3-0.35 0.3-0.35
Polythene Steel 0.2 0.2
Rubber Asphalt (Dry) 0.5-0.8
Rubber Asphalt (Wet) 0.25-0.0.75
Rubber Concrete (Dry) 0.6-0.85
Rubber Concrete (Wet) 0.45-0.75
Saphire Saphire 0.2 0.2
Silver Silver 1.4 0.55
Sintered Bronze Steel 0.13
Solids Rubber 1.0-4.0
Steel Aluminium Bros 0.45
Steel Brass 0.35 0.19
Steel (Mild) Brass 0.51 0.44
Steel (Mild) Cast Iron 0.23 0.183 0.133
Steel Cast Iron 0.4 0.21
Steel Copper Lead Alloy 0.22 0.16 0.145
Steel (Hard) Graphite 0.21 0.09
Steel Graphite 0.1 0.1
Steel (Mild) Lead 0.95 0.95 0.5 0.3
Steel (Mild) Phos Bros 0.34 0.173
Steel Phos Bros 0.35
Steel (Hard) Polythened 0.2 0.2
Steel (Hard) Polystyrene 0.3-0.35 0.3-0.35
Steel (Mild) Steel (Mild) 0.74 0.57 0.09-0.19
Steel (Hard) Steel (Hard) 0.78 0.42 0.05-0.11 0.029-.12
Steel Zinc (Plated on steel) 0.5 0.45
Teflon Steel 0.04 0.04 0.04
Teflon Teflon 0.04 0.04 0.04
Tin Cast Iron .32
Tungsten Carbide Tungsten Carbide 0.2-0.25 0.12
Tungsten Carbide Steel 0.4-0.6 0.08-0.2
Tungsten Carbide Copper 0.35
Tungsten Carbide Iron 0.8
Wood Wood (clean) 0.25-0.5
Wood Wood (Wet) 0.2
Wood Metals(Clean) 0.2-0.6
Wood Metals(Wet) 0.2
Wood Brick 0.6
Wood Concrete 0.62
Zinc Zinc 0.6 0.04
Zinc Cast Iron 0.85 0.21

Plastics Selection Chart

PlasticsSelectionChart.pdf

Plastics Selection Chart
Common Name Properties Uses Common Forms Cost
Polyester resin                    (Unsaturated polyester resin) Good electrical insulator, good heat resistance.  Stiff, hard, brittle alone but strong and resilient when laminated.  Resistant to ultraviolet light for outside use. Strongly exothermic, this can lead to cracking.  Contracts on curing. GRP boats, car bodies.  Chair shells.  Ducting, garden furniture, e.t.c.  Translucent panels for building.  Encapsulating and embedding castings. Liquids.  Pastes. Medium
Low density polythene   (Low density polyethylene) Wide range of colors. Tough.  Good chemical resistance. Good elecrical insulator. Flexible, soft.  Fades unless light stabilized.  Attracts dust unless anti-static. Squeeze bottles and toys.  Plastic sacks and sheets.  Packaging film.  Telecommunications cable insulation. TV aerial lead insulation. Powders.  Granules.  Films.  Sheets.  Wide range of colors. Medium
High density polystyrene                          (High density polyethylene) Wide range of colors. Fairly stiff and hard.  Stiffness and softening point both increase with density.  Can be sterilized.  Good chemical resistance.  High impact and shock resistant. Fades unless light stabilized. Milk crates.  Bottles, barrels, tanks, pipes, chemical pumps, machine parts (e.g. gear wheels).  Houseware (e.g. buckets, bowls) Powders, granules, films.  Sheets.  Wide range of colors. Medium
Plasticized PVC                   (polyvinyl chloride) Wide range of colors.  Soft, flexible.  Good eletrical insulator. Leathercloth, suitcases, tabletops coverings, sealing compounds, underseal.  Dip coatings.  Hosepipes.  Electrical wiring insulation.  Wall coverings (vinyl wallpapers) Floor coverings. Powders, pastes. Liquids. Sheets.  Wide range of colors. Medium
Expanded polystyrene        (Expanded polyphenylethane) Very buoyant, light weight.  Absorbs shocks.  Very good sound and heat resistor.  Crumbles easily.  Burns readily unless flame proofed. Sound insulation.  Heat resistant packaging. Sheets, slabs, beads.  Usually white. Low
Acrylic                                      (Polymethyl methacrylate) Stiff, hard glass clear.  Very durable outdoors.  Easily machined, cemented and polished.  Good electrical insulator.  Safe with food.  Ten times more impact resistance than glass.  Splinters easily.  Scratches easily. Light units and illuminated signs. Watch and clock glasses.  Record player lids.  Simple lenses.  Aircraft canoplex and windows.  Car rearlight units.  Skylights.  Furniture.  Baths.  Perspex sheet.  Cladding for buildings. Rods, tubes which are usually clear.  Translucent and opaque.  Comes in a wide range of colors. Medium