SIST EN 1071-12:2010

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Hochleistungskeramik - Verfahren zur Prüfung keramischer Schichten - Teil 12: Schwingungs-VerschleißprüfungCéramiques techniques avancées - Méthodes d'essai pour revêtements céramiques - Partie 12 : Essai d'usure en vaet-vientAdvanced technical ceramics - Methods of test for ceramic coatings - Part 12: Reciprocating wear test81.060.30Sodobna keramikaAdvanced ceramics25.220.99Druge obdelave in prevlekeOther treatments and coatingsICS:Ta slovenski standard je istoveten z:EN 1071-12:2010SIST EN 1071-12:2010en,de01-maj-2010SIST EN 1071-12:2010SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 1071-12
March 2010 ICS 81.060.30 English Version
Advanced technical ceramics - Methods of test for ceramic coatings - Part 12: Reciprocating wear test
Céramiques techniques avancées - Méthodes d'essai pour revêtements céramiques - Partie 12 : Essai d'usure en va-et-vient
Hochleistungskeramik - Verfahren zur Prüfung keramischer Schichten - Teil 12: Schwingungs-Verschleißprüfung This European Standard was approved by CEN on 30 January 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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Issues related to dynamic measurements in reciprocating wear testing . 18A.1 Resonant frequencies . 18A.2 Frequency response . 18A.3 Phase angle errors. 19A.4 Further guidance. 21Annex B (informative)
Methods for the determination of coating properties likely to be relevant to coating performance in a reciprocating wear test . 22B.1 Relevant properties . 22B.2 Phase composition and preferred orientation. . 22B.3 Residual stress . 22B.4 Hardness . 22Annex C (informative)
Examples of common wear mechanisms . 23Annex D (informative)
Determination of volume loss from the pin using profilometry . 24Annex E (informative)
Determination of wear of coated plate by ball crater technique . 25Bibliography . 28 SIST EN 1071-12:2010

Methods of test for ceramic coatings, consists of the following 13 parts:  Part 1: Determination of coating thickness by contact probe filometer  Part 2: Determination of coating thickness by the crater grinding method  Part 3: Determination of adhesion and other mechanical failure modes by a scratch test  Part 4: Determination of chemical composition by electron probe microanalysis (EPMA)  Part 5: Determination of porosity (withdrawn)  Part 6: Determination of the abrasion resistance of coatings by a micro-abrasion wear test  Part 7: Determination of hardness and Young's modulus by instrumented indentation (withdrawn)  Part 8: Rockwell indentation test for evaluation of adhesion  Part 9: Determination of fracture strain  Part 10: Determination of coating thickness by cross sectioning  Part 11: Determination of internal stress by the Stoney formula  Part 12: Reciprocating wear test  Part 13: Determination of wear rate by the pin-on-disk method Parts 8 and 11 are Technical Specifications. CEN/TS 1071-7:2003 was withdrawn on publication of EN ISO 14577-4:2007. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 1071-12:2010

Introduction Proper evaluation of the wear performance of ceramic coatings is essential to understanding their behaviour and to increasing their use in applications where high performance and predictable life are critical requirements, for example in the aerospace, automotive and biomedical industries. This part of EN 1071 describes a technique for the determination of the wear behaviour of a ceramic coating by reciprocating, under load, a flat or spherically ended pin against a flat plate. Depending on the information required, either the plate or pin or both may be coated with the material under test, with the other member of the couple being selected for its relevance to the system under evaluation. Wear is determined by weight loss, by profilometry, by linear measurement or by a combination of these. Coatings may be tested under dry or lubricated conditions. Where suitable instrumentation is available, the test can provide important information about the friction generated in the system. In addition to providing data on the frictional interaction in the system per se, monitoring of the friction can, by detecting changes in the level or trend of the friction force, provide important information about changes occurring during the test, e.g. removal or fracture of the coating, changes in wear mechanisms, etc. The test for use with bulk materials reciprocating under non-lubricated conditions is well described in [1]. The standard identifies the basic equipment requirements and the test critical parameters for testing ceramic coatings, and provides for appropriate operating procedures and measurement protocols to ensure their proper control. In addition, it provides for consistency in the analysis of data and in the treatment of errors.
This part of EN 1071 complements parts 6 [2] and 13 [3], which describe techniques for micro-scale abrasion wear testing and pin-on-disc wear testing of ceramic coatings respectively. SIST EN 1071-12:2010

1 Scope 1.1 This European Standard describes a method for evaluating the wear of ceramic coatings by use of a reciprocating wear test whereby a flat or spherically ended pin is reciprocated, under load, against a flat plate. Depending on the conditions being simulated, either the pin or plate or both may be coated with the material under test, with the other member of the couple being selected for its relevance to the system under evaluation. The method described is considered to be not suitable for evaluating fretting wear. 1.2 The method is intended for evaluating coatings with a thickness of more than 1 µm, though might also be used for testing thinner coatings. 1.3 The test may be carried out under either dry or lubricated conditions. However, the test is not designed for evaluating the properties of lubricants except insofar as they affect the wear behaviour of the materials being tested. Related methods for testing lubricants using reciprocating motion are given in references [4] – [6]. 1.4 Testing a materials couple under a range of loading conditions might provide information about the adhesive and/or cohesive strength of the coating, in addition to its wear behaviour.
Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1
wear track line of contact of pin on plate during reciprocation 3.2 wear scar worn region on the test specimen 3.3 volume wear rate
volume wear coefficient
specific wear rate volume of material removed from a surface in a sliding distance of 1 m under a normal load of 1 N
3.4
mass wear rate
mass wear coefficient mass of material removed from a surface in a sliding distance of 1 m under a normal load of 1 N SIST EN 1071-12:2010

3.5
stroke length total distance traversed by the leading or trailing edge of the pin over the surface of the plate between consecutive reversals in the direction of motion 3.6
instantaneous coefficient of friction instantaneous value of the friction force divided by the instantaneous value of the applied load
NOTE This is often approximated to the instantaneous value of the friction force divided by the applied load. 3.7 cycle average coefficient of friction average value of the instantaneous coefficient of friction calculated for a complete cycle of reciprocation NOTE
Three possible ways of calculating the cycle average coefficient of friction are:  to average the absolute magnitude of the friction, excluding the values towards the end of the stroke where the value is affected by the pin stopping, and to divide this by the applied load;  to determine the area under the coefficient of friction-horizontal motion curve for a complete stroke and divide this by twice the stroke length – see Figure 1;  to pass the instantaneous friction signal through a true analogue r.m.s. to d.c. converter amplifier, the output from which is then data logged at an appropriate sampling rate, which can be quite modest (typically 1 Hz to 10 Hz). Again the average friction signal obtained over a complete cycle should be divided by the applied load to obtain the cycle average coefficient of friction. 12-3-2-10123-0,4-0,20,00,20,4 Key 1 Friction coefficient 2 Horizontal displacement, in millimetres (mm) Figure 1
Coefficient of friction – Horizontal displacement loop for reciprocating test with alumina ball rubbing against titanium nitride coated plate [11] SIST EN 1071-12:2010

Although it is relatively easy in a reciprocating wear test to reproduce the contact stress experienced in a specific tribological contact, it might be necessary to use additional heating to ensure that the contact temperature approximates to that of the contact being simulated. 5 Principle The test consists in reciprocating a loaded pin against a flat plate and determining the wear of one or both components. Depending on the wearing system being simulated, either the pin or plate or both may be coated with the ceramic coating under test, and the test may be carried out either with or without lubrication. The pin contact face may have either a flat or rounded geometry. If the former is chosen, great care is necessary in order to ensure that the contact faces of pin and plate both lie in the same plane, as any variation from this will produce substantially different contact conditions from those expected for a plane contact. The high contact stress generated by misalignment can be particularly damaging to brittle ceramic materials and can lead to spurious and un-reproducible results. If a rounded geometry is chosen, then the contact conditions will vary throughout the test and affect the analysis of the results. 6 Apparatus and materials 6.1 Apparatus construction 6.1.1 General The apparatus shall be rigid such that, during use under the maximum recommended load and reciprocating speed, the axis of the pin remains orthogonal to the plane of the test surface of the plate at all times.
NOTE 1
Whilst it might be more common for the pin and plate to be held rigidly during the test, additional rotary motion of the pin has been used, e.g. to simulate the conditions encountered in an artificial hip [7]. Where such an approach is adopted, care is necessary to ensure that the axis of the pin remains rigidly orthogonal to the plane of motion of the contacting surfaces. Modelling has shown that, depending on the pin geometry adopted, misalignments of as little as 0,5° can result in more than a tenfold increase in the actual contact stress [8]. Reciprocation may be achieved by means of a crank mechanism driven from an eccentric cam, a linear, electromagnetic actuator drive with sinusoidal motion, or other suitable arrangement, and either the pin or plate may be driven, whilst the other remains stationary. Whatever mechanism is chosen to produce the reciprocation, the motion produced shall be smooth and free from any erratic behaviour. The type of motion used in the test shall be reported, preferably by presenting a position versus time or velocity versus time plot for a full cycle of reciprocation. SIST EN 1071-12:2010

It should be appreciated that different test orientations might produce different results for apparently identical test conditions as a consequence of retention of, or loss of wear debris from the contact. Loading between the pin and the plate may be achieved using dead loading with weights, and may be increased by use of a lever arrangement if necessary; with a calibrated spring, again using a lever arrangement if necessary; or using other suitable means. Whatever loading arrangement is used in the equipment selected it shall be such as to ensure that the load remains nominally constant throughout the duration of the test. The magnitude of the load applied can be determined by the use of suitably calibrated weights, by means of a suitably calibrated load cell, or by other suitable means. However, in all cases the load determined shall be the contact load between pin and plate.
NOTE 3
Dead weight loading systems produce more severe conditions than low mass loading systems (for example spring or pneumatic actuation). This is because, with dynamic conditions, inertia gives rise to shock loading. Dead weight loading systems should be avoided at anything other than very modest reciprocation frequencies, the magnitude of which will depend upon the precise test conditions. Where flat-ended pins are to be used, suitable means shall be provided to ensure conformance between the pin and the plate in order that the contact conditions are reproducible and so that the contact stress can be calculated, if required. NOTE 4
One technique that has been used to ensure conformance between a flat ended pin and the surface of the plate has been to grind a flat onto a spherical ball and to mount the ball into a spherical cavity, of the same diameter as the ball, which has been machined into the end of the pin – see Figure 2. Contacting the flat on the ball with the surface of the plate will ensure that conformity is obtained. The use of a pin with a spherical cavity will also enable a ball of the same radius of curvature to be accommodated and to act as a ball-ended pin.
In all cases where the geometry referred to in Note 4 is used, the centre of curvature of the cavity shall lie on the, extended, axis of the pin. Equipment shall be provided with a suitable means to deliver appropriate lubricant to the contact zone and, where appropriate, means to collect used lubricant so as to enable, where required, the isolation and analysis of wear debris. NOTE 5
Some investigators have immersed the contact zone of the plate and pin in a bath of fluid. This approach is appropriate for some situations, e.g. for simulating the wear of artificial joints [7]. 12 Key 1 Cylindrical pin with spherical cavity of same radius as ball and centred on extended axis of pin 2 Ball with ground flat Figure 2
Diagram showing possible arrangement to obtain conforming contact between "pin" and plate – see 6.1.1, Note 4 SIST EN 1071-12:2010

In view of the dynamics of reciprocating wear testing, the use of piezoelectric force transducer should be preferred for friction measurement. Although the use of other types of transducers is not prohibited by this standard, due consideration should be given to the relevance of the information obtained by their use. NOTE 2
It is recommended that a sampling rate of at least 100 samples per reciprocation be used.
NOTE 3
The method of mechanical attachment of the friction force transducer to the apparatus can affect the results obtained. A common practice is to rest the pin holder against the measurement point of the transducer. In this case care is necessary to eliminate friction between the pin holder and the transducer as this might alter the nominal loading between pin and plate. It should be recognised that this arrangement gives different dynamic characteristics to the situation where the pin holder is clamped to the machine frame through the friction transducer. 6.2 Operating environment The equipment shall be maintained in a constant environment, fixed temperature and humidity, e.g. by enclosing it in a suitable cabinet or by operating it in an environmentally controlled laboratory. Care should be taken to avoid accidental contamination of the apparatus with lubricants or other materials that might affect the wear process, e.g. from spray mist from adjacent equipment. Where fresh lubricant is delivered continuously to the contact zone it shall be stored and delivered in such a way as to ensure that its temperature at delivery is nominally constant. NOTE 1
Although precise temperature and humidity conditions are not prescribed in this standard, typical ambient operating conditions are: temperature = (23 ± 2) °C; and humidity = (50 ±10) %.
NOTE 2
The use of a constant environment is required to help ensure the stable operation of the test equipment, and it should not be considered a requirement of this standard that the tribological contact itself should be maintained under the same fixed conditions. Indeed, there are many situations where additional heating of the contact will be required to help ensure the conditions approximate to those in the contact being simulated.
NOTE 3
It has been found for some ceramic materials, see [9] and [10], that variations in humidity, particularly at low levels of humidity (< 40 %), can have far greater influence on the test results than variations in temperature. Report the precise conditions used during the test. 7 Preparation of test pieces 7.1 Substrate material and preparation Where the test is used to simulate the working conditions in a mechanical device it is recommended that the substrate materials chosen for both pin and plate be representative of the couple in that device. The materials should, where practical, have the same heat-treatment and surface preparation as the components being simulated so as to ensure that they possess the same load bearing capacity and surface texture.
In cases where the test is being used to rank coatings without a specific application in mind, both pin and plate should be made from materials that will have minimum elastic and zero plastic deformation under the test conditions used. Depending on the test conditions to be investigated, such materials might be cemented carbide, cermets, SiC, alumina (> 96 %), hardened and tempered high speed steel, e.g. UNS T 11302 SIST EN 1071-12:2010

In the absence of other requirements, the contact surfaces of both pin and plate shall be polished to a surface finish equal to or better than 0,02 µm Ra (see ISO 4288) using polishing materials compatible with subsequent coating operations. The surface of the plate shall have a flatness better that 0,01 mm (see ISO 1101) and this condition shall also apply to the contact face of flat ended pins, where used. Care should be taken to ensure that polished surfaces are free from embedded polishing material as this might significantly affect the test results.
Where a flat-ended pin is used, the flat end shall be orthogonal to the axis of the pin. Where a spherically-ended pin is used, the centre of curvature of the contact face shall lie on the axis of the pin. NOTE 1
Balls may be used in place of spherically-ended pins provided that they are held rigidly throughout the duration of the test. Pin and plate dimensions shall be such that no bending of the pin or test surface of the plate occurs during the test. NOTE 2
Although the dimensions of the test plate and pin are not prescribed in this standard, an example of dimensions that have been used for the plate is 80 mm long, 20 mm wide and 10 mm thick, and for the pin is 10 mm diameter and 20 mm long.
7.2 Coating deposition Where the test is being used to simulate the working conditions in a mechanical device, the substrate cleaning and deposition conditions selected for the coating shall be as near as practical the same as those that would be used for the components in that device. In particular, those process conditions that might influence the adhesion, chemical phase, preferred orientation or residual stress of the material being deposited should be carefully monitored and controlled. In all cases, all relevant deposition conditions shall be recorded and this record shall form part of the test report. NOTE 1
In view of the likely influence of the adhesion, chemical phase, preferred orientation and residual stress on the coating performance, it is recommended that determination of these properties of the coating be made and the results reported. Techniques for determining these additional properties of ceramic coatings are reviewed in Annex B. In cases where the test is being used to rank coatings without a specific application in mind, deposition of the coating should follow normal procedures for the material under investigation. If no normal procedures exist, for example because the test forms part of a coatings development programme, then care should be taken to ensure that the conditions used are reproducible. Coating thickness should, where practical, be the same as that used in the device being simulated.
NOTE 2
If no device is being simulated then, depending on the purpose of the test, it is recommended that a range of coating thickness be evaluated. 7.3 Post-coating preparation In some instances, e.g. where the deposited coating is rough, the surface of the coating should be prepared in some way, e.g. by polishing, following its deposition. All procedures that modify the surface of the coating shall be documented in such a way that they are completely reproducible and this record shall form part of the test report. Where post-deposition preparation of the coating surface is used, care should be taken to remove all extraneous materials from the surface after treatment. NOTE
Care should be taken to minimise material removal during any polishing operation SIST EN 1071-12:2010

The procedure used for cleaning test pieces should be detailed in the test report. NOTE
Ferromagnetic materials having residual magnetism should be demagnetised before cleaning.
8 Test procedure 8.1 Selection of test conditions Prior to undertaking a test programme it should be appreciated that the conditions selected can have a marked influence on the results obtained. This not only applies in the case of variables such as contact stress, reciprocation frequency and stroke length but also to the ratio (contact length):(stroke length). This ratio plays an important role in two ways. Firstly, if the contact length between pin and plate in the direction of motion is greater than the stroke length, the pin will remain in contact with the central region of the wear track at all times whilst the ends of the wear track will be exposed once per cycle. This affects the entrainment and discharge of debris, with a greater tendency for debris to become trapped in the mid-stroke position. In lubricated tests, it affects both lubricant entrainment and the behaviour of lubricant additive chemistry. With regard to the latter, the lubricant at either end of the stroke is exposed to atmosphere once per cycle. Hence, with this ratio of contact length to stroke length, two different tribological regimes can be identified. To overcome this problem and depending on the conditions being simulated, it is preferable to ensure that the contact length is less than the stroke length. Secondly, the ratio of the contact length to the stroke length also influences how the linear wear is shared between the two surfaces. Consider two pins with contact lengths a and b. For a given number of cycles of reciprocation n and stroke length l, a given point on each pin will slide a distance of 2nl. However, the sliding distance for a given point on the plate for the first pin will be 2na, whilst that for the second pin will be 2nb. Hence the ratio (sliding distance pin):(sliding distance plate) will be l:a for the first pin and l:b for the second pin. 8.2 Preliminary set-up If suitable equipment is available, determine the masses of the pin and the plate to at least the nearest 0,01 mg, preferably 0,001 mg, using a calibrated balance. The mass determination should be made after components have been left to equilibrate in the same temperature and humidity controlled room or cabinet as the balance. NOTE 1
Measurements have indicated that up to 24 h might be necessary for such equilibration. If the reciprocation length can be varied set it to the value to be used in the test.
Mount the pin and plate in the normal way, ensuring that the test surface of the plate is level with respect to the reciprocation. Ensure that the pin and plate are rigidly fixed by or in their clamping devices. NOTE 2
Levelling of the test surface of the plate can be checked by the use of a suitable clock gauge, or by ensuring that the force exerted between the pin and plate remains constant over a complete cycle of reciprocation by e.g. use of a calibrated load cell mounted on the plate. SIST EN 1071-12:2010

In the case of lubricated tests it is important to ensure that the test takes place under boundary lubrication conditions. NOTE 2 A typical reciprocation frequency is 1 Hz but the value selected will depend upon the conditions being simulated.
At the end of the test, switch off the reciprocation, record the total number of reciprocations, record the temperature and humidity, if continuous monitoring of these is not available. Switch off the flow of lubricant, if used, and check the zero setting of the friction transducer, recording any offset that has occurred. Remove the test samples, collecting the lubricant/wear debris for analysis, if required. Inspect the pin and plate using a magnifying lens or microscope (minimum 10× magnification) and record any observations, e.g. presence of wear debris adhering to the surface. Clean the pin and plate in a suitable, clean solvent to remove lubricant and wear debris, collecting the wear debris as required. Dry the test pieces in hot air, and store in a desiccator until required for further testing or until evaluation of the wear can be undertaken. NOTE 3
Figure 3 shows an example of wear debris accumulation during reciprocating wear testing of a titanium nitride coating against an alumina ball [11]. Repeat the test at least three times using a new pin each time and either a new wear track on the plate, spaced at least the width of the previous wear scar away from any other wear scar, or a new plate. For repeat measurements, new pins and new plates, where used, shall be of the same material and have identical treatments to all other samples of the same type in the measurement set.
NOTE 4
For some situations, important additional information can be obtained by carrying out a series of tests with the same pin and plate, using the same wear track. This can indicate, for example, how much running-in occurs or whether a steady-state wear situation has been reached, etc. However, such experiments need to maintain a consistent orientation of the pin and plate and to relocate the pin in the existing wear scar.
NOTE 5
Where testing a range of conditions, it might be acceptable to undertake one test only at each condition and to use statistical techniques to evaluate typical errors. Where only a limited test programme can be undertaken, such an approach could provide results from a wider range of conditions, which is likely to be more useful than more accurate information about the response to a very limited set of conditions. SIST EN 1071-12:2010

Figure 3
Photograph of wear debris produced during reciprocation of an alumina ball on a titanium nitride coated plate 8.4 Evaluation of wear 8.4.1 Preliminary inspection 8.4.1.1 Friction trace Inspect the friction v's time trace, if available, for changes in behaviour that might indicate significant events, e.g. fracture or removal of the coating, or a change in the wear mechanism. Record all such observations. Determine the cycle average coefficient of friction at the start (when the trace has stabilised), middle and end of the test and report these values in the test report. 8.4.1.2 Samples
Using a microscope with a minimum magnification of 10×, inspect the worn areas of the pin and plate for the following: a) breakthrough or removal of the coating; b) uneven or irregular wear; c) transfer of material from one surface to the other; d) build-up of wear debris on one or both surfaces. If the former of these is observed then it will only be possible to determine an overall component wear rate and not a wear rate for the coating, and if any of the remaining is observed care will need to be exercised in the determination of the wear volume.
Assess the wear mechanisms occurring during the test, using a higher magnification if necessary. Examples of the most common wear mechanisms are shown in Annex C. Report the observations made in the test report. SIST EN 1071-12:2010

Methods that might be suitable for the determination of coating density are described in DIN 53217 Pt 1 [12] and ASTM B 767 [13]. 8.4.2.3 Volume loss by profilometry 8.4.2.3.1 Plate If a calibrated 3-d profilometer is available, determine the volume profile of the wear scar along its entire length and from this determine the volume loss.
Alternatively, if a 3-d profilometer is not available use the following procedure:
Using a calibrated, contact or non-contact linear profilometer, determine the profile of the wear scar at a minimum of five equi-spaced points along its length, with the first and last determinations being made at a distance equal to the diameter of the contact face of the pin, after completion of the test, from each end of the scar. From these profiles determine the width and average depth at each measurement point (w1, w2, …wn, and d1, d2, …dn, where n is the number of measurement points). From these values calculate the average width, wa (where wa = {w1 + w2 … + wn}/n), and the average depth, da (where da = {d1 + d2 . + dn}/n). Measure the overall length, l, of the wear scar using a calibrated travelling microscope or other suitable means. Calculate the volume lost, V, using the following formula: 4/)()(2aaaaadwdwwlVπ+−= (1)
Alternatively, if after completion of the test the wear scar is less than or equal to about two times the diameter of the contact face of the pin then it is recommended that the wear volume be calculated in the following way. Take a series of equi-spaced profilometer traces across the width of the scar so that the true shape is well established – an odd number of traces is recommended. Determine the cross sectional area at each point by multiplying the width by the average depth. From these results determine the average cross sectional area SIST EN 1071-12:2010
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