127FT L 015 Friction

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S.A.S. au capital de 1 440 000 R.C.S. Lyon B 954 504 742 Siret : 954 504 742 00030 N ident. TVA FR 33 954 504 742 Code NAF 2562B

OUTILS ET SYSTEMES EVOLUES POUR LE CONDITIONNEMENT DES POUDRES ET DES LIQUIDES

FRICTION

A friction coefficient on its own is not enought to characterize a material.Only a material PAIRING can be used to identify a coefficient. Then we needto distinguish between slip and adhesion. The former is a characteristic ofresistance to displacement during an established phase of movement whilethe other analyses the force required to put the elements observed in motion

from a static position. That is why a motor vehicle comes to a halt fasterwhen its tyres do not slip, that is to say when roadholding conditions aregood.The friction coefficient is the expression of the F/P ratio where F is the forceneeded to enable the moving component to slide and P is its weight.

The friction or slip coefficient value depends on:(by decreasing order of importance)

the pair of materials in contact. lubrication. the surface finish of the materials. temperature.

The adhesion coefficient value for a given pair of materials will beequal to or greater than the friction coefficient because of the greaterimpact made by the surface finish.Nevertheless, as a first approximation and in most cases, it isperfectly reasonable to combine the two figures.

The friction coefficient value does not depend on: the geometric nature and the dimension of the surfaces in contact. the intensity of the normal effort.

The adhesion coefficient value can vary according to: the geometric nature and the dimension of the surfaces in contact. the intensity of the normal effort.

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FRICTION COEFFICIENT FOR THE MAIN MATERIALS

N.B.

The slip effort rises with the level of the friction coefficient or of adhesionfactor.

Materials Materials ContactFriction

coefficientAdhesioncoefficient

Steel Steel - 0.1 0.2

Steel Steel grease 0.05 0.1

Hardened steel Hardened steel oil 0.1 / 0.07 0.11

Hardened steel Hardened steeloil underpressure

0.05 0.11

Steel XC35 water 0.25 .

XC35 XC35 oil 0.09 .

16NC6 steel Steel water 0.065 .

Case-hardenedsteel

Chilled cast iron - 0.15 .

Case-hardenedsteel

Chilled cast iron lubricated 0.08 .

Steel Cast iron lubricated 0.08 / 0.05 0.08

Steel Cast iron - 0.1 0.12

Z30C13 steel Grey cast iron alloy oil 0.23

16NC6 steel AU4G water 0.45 .16NC6 steel AU4G vaseline 0.075 .

Hardened steel Hardened bronze - 0.25 /0.15 0.2

Hardened steel Hardened bronze lubricated 0.12 0.2

Hardened steel Hardened bronzeoil underpressure

0.05 0.11 / 0.12

16NC6 steel CuSn12Zn1Pwater/vaselin

e0.17 .

Chromium-plated stainless

steelAluminium - 0.4 .

Chromiumplated stainless

steelAluminium lubricated 0.1 .

Steel Tinplated copper - 0.12 .

Steel Tinplated copper lubricated 0.09 .

Steel Sintered metal - 0.1/0.12 .

Steel Sintered metal lubricated 0.03/0.06 .

Steel Ferrodo - 0.25/0.35 .

Steel Graphite lubricated 0.09 .

Graphite steel Teflon - 0.1 .

Graphite steel Teflon (PTFE) lubricated 0.05/0.08 .

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Steel Teflon (PTFE) - 0.1 0.15

Stainless steel Graphite teflon water 0.06 .

Steel PTFE bearing block - 0.02/0.08 .

Steel PTFE bearing block lubricated 0.003! /0.05 .

Steel Polyethylene - 0.3/0.8 .

Steel Nylon - 0.15 0.2

Steel Nylon water 0.5 .

Steel Nylon oil 0.1 0.15

Steel Acetal oil 0.2 .

Steel Polyamide 6.6 oil 0.12 .

Grey cast ironalloy Machined ductilecast iron oil 0.13 .

Grey cast ironalloy

White cast iron oil 0.11 .

Cast iron Bronze - 0.21 0.43

Cast iron Rubber - 0.20 0.80

Burnished castiron

Leather - 0.10 0.43

Burnished castiron

Leather fat 0.20 0.43

Burnished castiron New rope - 0.075 0.79

Bronze Bronze - 0.20 0.43

Rubber Burnished cast iron - 0.20 0.80

Rubber Average floor - 0.65 0.80

Rubber Average floor wet 0.30 0.80

Rubber Average floor muddy 0.10 0.80

Rubber Average floor very wet 0.25 0.80

Tyre Road - 0.5/0.6 .

Tyre Road wet 0.3/0.5 .

Tyre Asphalt at 25km/hour - 0.02/0.03 .

Iron wheelsGood condition

asphalt- 0.010 .

Iron wheels Stone slabs - 0.006 .

Iron wheels Dry rails - 0.35 .

Iron wheels Wood slabs - 0.018 .

Iron wheels Stone slabs - 0.02 .

Iron wheelsStone slabs in poor

repair- 0.033 .

Iron wheelsCobbled road in

good repair - 0.023 .

Iron wheelsCobbled road industy conditions

- 0.028 .

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Iron wheels

Uneven cobbled

road, muddy - 0.035 .

Iron wheelsEarth track in good

condition- 0.08 .

Iron wheelsEarth track in poor

condition- 0.16 .

Iron wheels Sand - 0.15 /0.30 .

Oak Oak - 0.34 0.54

Oak Oak rubbed 0.16 0.44

Oak Oak wet 0.25 0.71

Oak New rope - 0.52 0.80

Oak Leather - 0.33 0.43

Oak (graindirection)

Iron wet 0.26 0.65

Beads Flat - 0.05 .

Pebbles Flat - 0.005 .

Bearings rail - 0.003 .

Ball bushing Pins - 0.002 .

TECHNICAL CERAMICS

Friction coefficient for pairs of materials involving ceramics are not availableat present. However, experience has shown that results are similar to thoserecorded for steel.

127FT L 015 Friction

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