ASTM Wear Testing

Wear 225–229 Ž1999. 1159–1170

Development and use of ASTM standards for wear testing Peter J. Blau a

a,)

, Kenneth G. Budinski

1

b

Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6063, USA b Eastman Kodak, Rochester, NY 14652-4347 USA

Abstract Standard wear test methods have been developed under the auspices of various ASTM technical committees. Committee G-2 on ‘Wear and Erosion’ was established in 1964 and has been a leader in developing such standards. Some ASTM wear testing standards are aimed at specific components, like the jaws of rock crushers, but others are designed to determine a material’s resistance to a specific wear type, like solid-particle erosion or two-body abrasive wear. Having identified a need for a new wear testing standard, ASTM G-2 typically follows a process of first assigning responsibility to a relevant subcommittee. The subcommittee chair may then decide to establish a task group to develop the given method, conduct one or more inter-laboratory testing programs, write a draft standard, conduct ballots, and revise or rewrite the draft standard to achieve consensus. Since the repeatability and reproducibility varies between test methods, understanding the role of instrumental and measurement factors of each wear testing standard is critical before it can become approved. In addition, each standard is critically reviewed on a continuing 5-year basis, and revised or updated as needed. This paper describes the development of standard wear testing methods and provides five examples of how ASTM G-2 wear testing standards were used to help solve important industrial problems involving sliding wear, abrasive wear, galling, and erosive wear. q 1999 Published by Elsevier Science S.A. All rights reserved. Keywords: Wear; ASTM G-2; Erosion; Galling

1. Introduction There are many types of wear test methods both because there are many types of wear and because there are many different situations in which wear has become a problem. Wear test methods fall into any of several categories. Some wear test methods are aimed at a specific type of material, such as wear test methods for plastics w1x. Some are aimed at evaluating a material’s response to a specific type of wear, such as solid–particle erosion, sliding wear, or two-body abrasive wear. Other wear tests are designed to simulate a particular field application in order to screen materials, surface treatments, or lubricants for

)

Corresponding author. Tel.: q1-423-574-5377; fax: q1-423-5746918; E-mail: [email protected] 1 The research of the first author was sponsored in part by the U.S. Department of Energy, Office of Transportation Technologies, High Temperature Materials Laboratory User Program, under contract DEAC05-96OR 22464 with Lockheed Martin Energy Research.

that type of service. Finally, some wear tests are intended for fundamental research into the basic nature of wear. Standard wear test methods have been used for all of these reasons, but like any type of wear test, standard test methods have both strengths and limitations. The principal advantages of using ASTM standard wear test methods are: Ž1. the test methods have been rigorously evaluated and the procedures carefully documented; Ž2. the repeatability and reproducibility of results tends to be better documented and understood than for specialized or one-of-a-kind types of wear testing machines; Ž3. in many cases, a great deal of previous data exists and it is convenient to compare new results with the existing data; and Ž4. documentation and reporting requirements have been established so that all the major variables and results of the work can be presented in a complete and organized manner. On the other hand, there are occasions when no ASTM test method satisfactorily meets the current need for wear data. Perhaps it does not simulate an intended application sufficiently well, or perhaps the specified testing parameters lie outside the interests of the current investigation.

0043-1648r99r$ - see front matter q 1999 Published by Elsevier Science S.A. All rights reserved. PII: S 0 0 4 3 - 1 6 4 8 Ž 9 9 . 0 0 0 4 5 - 9

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P.J. Blau, K.G. Budinskir Wear 225–229 (1999) 1159–1170

Table 1 ASTM wear tests developed by several committees Designation

Test description

D-4172 D-4170 G-32 G-56 G-65 G-73 G-75 G-76 G-77 G-81 G-83 G-98 G-99 G-105 G-119 G-132 G-133 G-134 G-137

Wear preventive characteristics of lubricating fluids Fretting wear protection by lubricating greases Vibratory cavitation erosion test Abrasiveness of ink-impregnated fabric printer ribbons Dry sandrrubber wheel abrasion test Liquid impingement erosion test Slurry abrasivity Erosion by solid particle impingement using gas jets Ranking resistance of materials to wear using block-on-ring wear test Jaw crusher gouging abrasion test Crossed-cylinder wear test Galling test Pin-on-disk test Wet sandrrubber wheel abrasion test Synergism between wear and corrosion Pin abrasion test methods Reciprocating sliding wear test Cavitating liquid jet erosion test Ranking resistance of plastic materials for sliding wear using a block-onring configuration

ASTM is an organization with about 36,000 members and 132 standards committees. Several of these committees have produced wear testing standards. A list of the ASTM wear testing standards is provided in Table 1. The number of standards changes periodically since each standard must be re-balloted for approval every 5 years, and new standards are added from time to time. The two committees which have produced more wear tests than the others are committee D-2 on Lubrication and Committee G-2 on Wear and Erosion.

The current paper focuses on the Committee G-2’s work in developing new wear testing standards, and illustrates how specific standards can be used to solve practical wear problems. Committee G-2 was formed in 1964, based on a growing interest in erosive wear, particularly in utility power plants. Since that time, the committee’s scope has widened to comprise other forms of wear as well. The breath of the committee’s interests is reflected in the continuing series of technical publications. Some of the standard wear test methods of today have resulted from

Fig. 1. Coefficient of variation within laboratories and between laboratories for five ASTM wear test methods. Data obtained from the respective standards documents.


needs identified in technical symposia and workshops organized by G-2 members.

2. How ASTM standard wear testing methods are developed Any new ASTM testing standard arises out of a need for the systematic collection of materials property measurements in a certain area of science or engineering. In the case of wear data, the usual process begins at the subcommittee level. The current standards-writing subcommittees in Committee G-2 on Wear and Erosion are G02.091—Erosion by Solids and Liquids, G02.20—Com-

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puterization in Wear, G02.30—Abrasive Wear, G02.40— Non-Abrasive Wear, G02.50—Friction, and G02.91— Terminology. Other subcommittees perform supporting functions like editorial review and long-range planning. When a proposal for a new standard is introduced and there is a consensus agreement within the subcommittee that a widespread need exists, then the subcommittee chairman may establish a task group in that area. The new task group draws its members from experts and interested parties, whether they are ASTM members or not. If several task group members possess wear machines which can provide certain agreed-upon conditions, then an interlaboratory test program can be conducted. Several rounds of interlaboratory tests may be needed to define the appropri-

Table 2 Typical variabilities of ASTM wear test methods ŽData from interlaboratory studies. Standard

Wear type

Material

Conditions

G-32

cavitation erosion

Ni 200

8.9

G-65

abrasion by sand between a specimen and a rubber wheel

4340 steel

20 Hz freq., 50 mm amplitude, distilled water at 25 " 28C, Žmax. loss rate in mmrh. 130 N force, 1000 revolutions Žwear loss in mm3 .

5.9

5.2

130 N force, 2000 revolutions Žwear loss in mm3 . 130 N force, 6000 revolutions Žwear loss in mm3 . 50 mm alumina particles, 30 mrs vel., 908 incidence, 2 grmin feed Žwear in mm3 rg erodant. 50 mm alumina particles, 70 mrs vel., 908 incidence, 2 grmin feed Žwear in mm3 rg erodant. 50 mm alumina particles, 70 mrs vel., 908 incidence, 2 grmin feed Žwear in mm3rg erodant. 134 N force, 72 rpm, 5400 revolutions, no lubricant Žwear of the block in mm3 .

2.4

3.5

6.4

19.3

17.1

29.3

3.4

17.0

4.9

21.0

37.6

18.8

134 N force, 197 rpm, 5400 revolutions, no lubricant Žwear of the block in mm3 .

14.9

40.2

803 N force, 72 rpm, 5400 revolutions, no lubricant Žwear of the block in mm3 .

25.9

25.9

25 N force, 5.0 Hz, 10 mm stroke Žwear of the flat specimen in mm3 . 200 N force, 10.0 Hz, 10 mm stroke, mineral oil Žwear of the flat specimen in mm3 .

34.7

–

23.7

48.6

4340 steel

G-76

erosion by particles in a gas stream

WC Ž20% Co. 1020 steel

1020 steel

304 stainless steel G-77

G-133

block sliding on a ring

reciprocating sliding

01 tool steel blockr 4620 steel ring 01 tool steel blockr 4620 steel ring 01 tool steel blockr 4620 steel ring self-mated Si 3 N4 self-mated Si 3 N4

a

Coefficient of variation, as defined in ASTM E-691.

Within-Lab COV a Ž%.

BetweenLab COV a Ž%. 20

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Fig. 2. Gravure pattern for toller application of coatings.

ate test conditions and establish which variables must be controlled to reduce any variability in the results. After successful interlaboratory testing is completed, a draft standard is written and submitted for editorial review. Then a subcommittee ballot is conducted. All negative ballots must be resolved either by revision of the draft, withdrawal of the negative, or being voted ‘non-persuasive’ after discussion. Having passed subcommittee, the main committee votes on the draft standard. All these procedures are instituted to assure that published ASTM wear test methods provide meaningful data for the users of the standards. Due to the rigors of the process, the time required to produce a new standard can range from 2 to 10 years. In addition, each standard for which a committee is responsible must be reapproved every 5 years to assure its

Fig. 4. Wear data for the doctor blade and gravure pattern. Top-unimplanted; bottom-implanted.

continuing validity and to incorporate new knowledge and measurement techniques.

3. Interlaboratory testing to validate a proposed standard wear test method The leader of the task group works to develop the set of operating instructions for the test, obtains materials, and assembles specimens for distribution to the participants. The procedures developed for the interlaboratory test series may eventually form the basis for the standard when the draft version is prepared. Interlaboratory tests are normally conducted in a manner which is prescribed by

Fig. 3. Schematic of the pin-on-disk testing machine.


ASTM E-691 w2x. This is done to ensure that the tests produce statistically valid information for establishing the precision of the test method. In addition, ASTM Committee G-2 has its own standard for reporting interlaboratory data specific to wear testing w3x. Two aspects of an interlaboratory test are particularly important: Ž1. establishing the repeatability of results within each participating laboratory and Ž2. establishing the reproducibility of the results from one laboratory to another. These are quite different issues. Sometimes data can be extremely consistent within

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a given laboratory but vary widely from one laboratory to another. Therefore, it is common to have to conduct several of rounds of interlaboratory tests until the reasons for any variabilities have been sorted out, and the group has identified all the aspects which must be controlled to assure consistent results. The data from interlaboratory programs may often be summarized in an appendix to the standard, and becomes part of the research report which is archived at ASTM headquarters to provide background information for each published standard.

Fig. 5. Scoring of a gear tooth.

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Fig. 1 shows the variability in data for five types of ASTM standard wear tests, as determined from interlaboratory studies and published in their respective standards documents. Table 2 provides information on the conditions and materials. Additional details, such as the numbers of participants and interpretation of the data, may be found in the referenced standards which appear in the ASTM Annual Book of Standards Volume 03.02 Ž1996.. The within-laboratory coefficients of variation ŽCOVs. range from 2.4% to above 37% and the between laboratory COVs range between 3.5% and up to nearly 50%. Of the data presented here, the dry sand–rubber wheel abrasive wear test exhibited the lowest COVs and the reciprocating wear test G-133 the highest. In majority of cases, the within-laboratory COVs are lower than the between laboratory COVs, but this is not always true. The information contained within standards therefore provides important information for determining whether the differences between wear values for candidate materials are truly significant or whether they fall within expected variations for that particular type of test. For sliding wear tests, it has been the authors’ experience that variations in friction and wear tend to be greater for unlubricated than for lubricated testing conditions. There are three major sources of wear data scatter: the testing machine, the operator’s technique, and the materials themselves. No source of error or variability can necessarily be ruled out a priori. The term ‘testing machine’ includes not only the calibration and construction of the machine, but also its proximity to sources of vibration and environmental cross-contamination. The operator’s technique includes such issues as judgment when making measurements, proper specimen handling and cleaning, attention to procedural details, and operator fatigue. The scatter in data can also result from microstructural heterogeneities or lot-to-lot variations within the materials themselves. The potential for material heterogeneities contributing to scatter raises the issue of whether it is feasible to produce standard reference materials to calibrate wear testing machines. Standard G-65 for dry sand–rubber wheel abrasion testing describes standard reference materials and how they are to be prepared for each of the optional testing procedures, and Standard Practice G-76 for liquid impingement erosion also suggests materials for use as reference. For example, ASTM G-65 specifies for its Procedure A reference material a D-2 tool steel which has been heat treated to a certain Rockwell C hardness and which will produce a mass loss of 36 " 5 mm3. Despite the desirability of having materials with which to calibrate wear machines, it is not an easy task to ensure that such materials can be produced in a consistent manner, and to in some manner certify that any specimen selected from within a characterized lot of reference material will fall within a given range in terms of wear rate or wear volume. While it is certainly possible for a testing laboratory to purchase

and maintain a large stock of carefully characterized reference materials and lubricants for future wear use, an alternative is to maintain and calibrate wear testing and measuring instruments using the best practices available. In addition, reference alloy specimens can corrode or develop surface films if not well protected, and lubricants can have a finite shelf life. The issue of reference material storage practices is important, but beyond the scope of this paper.

4. Applications of ASTM wear testing standards The following five case studies show how ASTM standard wear tests can be used to help evaluate and select materials for service in wear-critical applications. 4.1. Case study 1: ion implantation to increase the life of graÕure cylinders Gravure cylinders are rollers that are covered with surface dimples called ‘cells.’ These features ŽFig. 2. come in different sizes and depths. They are used to apply coatings to web surfaces. The gravure roller dips into a tray of the material to be coated. Then a doctor blade contacts the gravure cylinder and removes all of the material except what is retained in the cells. The gravure cylinder then contacts the web and deposits the coating on the web at a consistent thickness. These cylinders are used to apply a wide variety of coatings to flexible plastic webs. The steel spring doctor blade Ž47 HRC. can produce unacceptable wear of the cells on the chromium-plated gravure roller. Since the implantation of chromium and

Fig. 6. Schematic of the ASTM G-98 galling test arrangement.


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Table 3 Threshold galling stresses of candidate materials Upper specimen, ŽRockwell hardness.

Lower specimen, ŽRockwell hardness.

Threshold galling stress Žksi.

Steel 2 Ž61 HRC.U Steel 2 Ž57 HRC.U Steel 1 Ž59 HRC.U D2 Ž60 HRC. D2 Ž55 HRC. D2 Ž50 HRC. D2 Ž50 HRC.

Steel 2U Ž61 HRC. Steel 2U Ž57 HRC. Steel 2U Ž59 HRC. D2 Ž60 HRC. D2 Ž55 HRC. D2 Ž55 HRC. D2 Ž60 HRC.

) 40.0 10.0 ) 40.0 ) 40.0 10.0 2.5 5.0

U

Specimens taken from gears used in service.

other metals with various atomic species has been known to significantly improve wear life w4x, a study was conducted to determine if ion implantation of the would improve roller life without causing significant reduction in doctor blade life. The prime criterion for an acceptable tribosystem Žmaterials pairing. was increased uptime, compared with the present. The ASTM G-99 pin-on-disk wear test Žw5x, Fig. 3. was selected to compare ion-implanted with non-implanted chromium flat panels Ž3 panels. containing the same gravure cell patterns. Plasma-assisted N implantation was used at a dosage level recommended by the supplier. A flat-ended pin was made from Type 1080 steel Ž47 HRC., the same material as the doctor blade. Wear tests were conducted using test parameters to simulate the production system. Damage to the gravure cells and the ‘pin’ was measured by stylus profiling and converted to wear volume. As shown in Fig. 4, results of these tests indicated that implantation increased the wear of the doctor blade material. In fact, the doctor blade would have to be replaced almost three times as often with an implanted gravure cylinder, and this would have a negative impact on process time. Thus, a decision was made to seek an alternative solution. Use of this relatively simple ASTM test provided a fast answer on the feasibility of a candidate process and it avoided costly testing on production cylinders.

4.2. Case study 2: scoring of spur gears Spur gears, 150 mm in diameter, were used in a precision timing mechanism. They were made of air-hardening, high-carbon, high-chromium tool steel. One gear set had been running for 10 years without problems. One set, then another failed by pitch line scoring. Metallurgical studies indicated that severe adhesive wear occurred on the loaded side of a significant number of teeth Žsee Fig. 5.. This scoring caused timing errors and subsequent shutdown of a manufacturing operation, and the gears had to be replaced at significant cost. A study was conducted to determine the cause of these failures and propose a solution w6x. The gears were failing by severe ‘adhesive’ wear, and further investigation disclosed that the gear material composition had been changed by the gear supplier to a grade of high-carbon, high-chromium steel to allow the application of high-temperature, physical-vapor-deposited ŽPVD. coatings without loss of hardness. The hardness of the new gear material was 56 HRC, compared to a range of 56–58 HRC for the gear steels which did not fail. We wondered if a drop in Rockwell hardness of only two points would make the new steel more prone to galling. Gear scoring is due to adhesion under high load combined with relative motion between the mating gear teeth. The pin-on-flat galling test provides a reasonable simulation of this tribosystem. Therefore, we selected the ASTM

Fig. 7. Schematic of the reciprocating wear testing machine.

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Fig. 8. Arbitrary scale used to rank the degree of wear debris formation on the ball specimen Žtop. and flat specimen Žbottom..

G-98 test method for use in our galling evaluation w7x. The test involves rotation of a flat-ended pin Ž3608. under a predetermined normal force on a flat counterface Žsee Fig. 6.. The test metric is called the ‘threshold galling stress.’ It’s value is determined by conducting a series of tests with increasing the normal force until severe adhesive wear occurs. The threshold galling stress is the apparent contact stress at the highest load before galling starts. Table 3 compares the threshold galling stresses of seven material combinations. Results suggest that a minimum hardness of HRC 59 was needed with these steels to obtain maximum galling resistance. In summary, the ASTM G-98 galling test was used to uncover the reasons for an expensive gear failure. Following the initial work, G-98 was also used to screen and

select additional steels for the improved scoring resistance needed for their use in timing gears. 4.3. Case study 3: material couples for plastic-to-plastic sliding A potential contamination problem occurred in the development of an optical disk drive system. The drive system design specified the use of injection-molded plastics for a cam and follower mechanism that was used to move an actuator. Early polystyrene prototypes proved to be an unsuitable couple because both parts wore and produced debris which could contaminate the disk drive. The optical disk drive is very sensitive to particulate contaminants; hence, none are allowed, so freedom from

Fig. 9. Wear of candidate plastic riders reciprocating on a PTFE-filled acetal counterface. wŽa. acetal 12 N, Žb. acetal 4, Žc. acetalq PTFE, Žd. Nylon 6r6 q 10% aramidq 10% PTFE, Že. Nylon 6r6 q 30% glass q silicone, Žf. Nylon 6r6 q silicone.x


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Fig. 10. Schematic of contact slitting knives.

debris generation was just as important to this application as low wear. A study was therefore initiated to rank the wear resistance and lack of debris formation of various plastic–plastic couples. Both cam and follower materials were open to all candidates. However, the requirements were that they be comparable in cost to other engineering plastics and that they be injection-moldable. In addition, the tribosystem had to survive 100,000 actuations with wear less than 0.2 mm on the cam profile. Actuations were intermittent 3008 forward and reverse rotations of the cam against the follower under a 4 N normal force. The test method selected was a modified version of the ASTM G-132 w8x pin abrasion test method. ŽFig. 7. Procedural modifications were necessary to mimic the load and sliding distance of this particular tribosystem. It was also necessary to develop a rating system to quantify the type of debris produced from the wear tests. Fig. 8 shows the rating scheme which was used to quantify debris build-up on both the ball and flat specimens. Previous reciprocating motion tests with a wide variety of metal counterfaces indicated that poly-tetrafluoroethylene ŽPTFE.-filled acetal usually exhibits very low wear. Therefore, we used this material as the standard counterface Žflat specimen. with a variety of plastic sliders. The test length was 100,000 cycles and the stroke length matched that to be experienced in service. Test results indicated that nylon with a proprietary lubricant had acceptable wear, and its debris rating was ‘0’ Žsee Fig. 9.. This cost-effective screening procedure required only about 4 h of technician attention time and produced a candidate material couple for production testing. The recommended couple showed no wear or debris in prototype testing, and as a result, the component design was changed to use this couple. The high cost and long lead time of full-size prototype tests were prohibitive in

this case. Thus, laboratory screening tests are essential when dealing with unusual tribosystems such as plasticon-plastic. 4.4. Case study 4: materials for rotary slitter kniÕes Plastic webs, cloth, paper, sheet metal and many related materials are manufactured in wide roll format and then are slit to salable width, usually by rotary slitter knives. Some products, such as photographic film and paper, require very precise slitting with no debris generation. Many slitters use contacting knives, like those shown in Fig. 10 w9x. The knives usually have a very small area of contact with the material being slit, and knife wear is caused by a combination of metal-to-metal wear and abra-

Fig. 11. Schematic of the cross-cylinders test.

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Fig. 12. Summary of wear data for a variety of candidate material combinations tested with the crossed cylinders apparatus.


sive wear from the paper product. Thus, a study of a variety of candidate materials was conducted to find combinations with improved wear life over the present couple in slitting paper. The ASTM G-78 crossed-cylinder test w10x was selected for this work. A rotating cylinder is rubbed against the same size stationary cylinder, as shown in Fig. 11. Wear of the rotating member is assessed by measuring the volume of the groove formed on its outside diameter. Wear volume of the wear spot or ‘divot’ on the stationary cylinder is also measured, and together, the total system wear is determined. Test results on wide variety of candidate couples are shown in Fig. 12. These results clearly indicated that it is necessary to use cemented carbide for at least one member of the couple in order to get low system wear. This study indicated that replacing the current steel–steel couple with a tool steel-cemented carbide couple will produce a significant reduction in wear. Additional abrasion tests were conducted to rank these couples for paper abrasion resistance. These screening tests were essential because of the significant cost of testing different knives in slitting product. In addition to the set-up cost, if a knife couple worked poorly, it could produce unsalable product. Laboratory tests are again proved more cost-effective in this case. 4.5. Case study 5: erosiÕity of dicalcium phosphate A certain manufacturing facility was trying to assess the feasibility of replacing a containerized bulk handling system for dry-sand-like dicalcium phosphate powder with a fluidized pipe transfer system. The plan showed significant savings in reduced labor and improved quality Žpowder cleanliness.. But before making this large capital investment decision, it was necessary to know whether the piping system would be fraught with blowouts due to erosion at bends. If the powder material was abrasive, it would be necessary to use much more expensive wear-resistant piping Že.g., hardened steel, basalt-lined pipe, etc.. and this might make the whole project uneconomical ŽFig. 13.. A laboratory test program was initiated to determine if particulate dicalcium phosphate with a particle size range

Fig. 13.

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Table 4 Erosion rates of two steels after impingement by 2000 grams of various erodants Candidate alloy

Particle type

Erosion rate =10y8 Žmm3 rg.

316 stainless steel 316 stainless steel D2 tool steel 316 stainless steel D2 tool steel

dicalcium phosphate silica silica aluminum oxide aluminum oxide

6.4 582.6 750.1 968.2 1018.5

of 1–300 mm is abrasive to stainless steel or to hardened steel. There are several ways of assessing the erosivity of dry powers w11x, but since the proposed transport system conveys the product in the fluidized state with flowing air, it was decided that the system could be modeled in the laboratory using the ASTM G-76 impingement erosion test w12x. This test is essentially a sand-blasting nozzle aimed at a target material of choice. The standard test uses aluminum oxide particles, but we substituted dicalcium phosphate. The erosion rates of several test materials are shown in Table 4. Dicalcium phosphate by itself was capable of producing scratching abrasion on 300-series stainless steel, but used as a directed particle stream, it did not produce erosive wear. The impinging material apparently formed a protective coating on the target surface that in turn reduced the erosion rate to an insignificant level. Based on these results, it was recommended to install the pneumatic conveyance system with soft stainless steel piping. In service the system, worked as predicted by the ASTM laboratory test method, and significant savings were realized.

5. Summary ASTM committee G-2 friction and wear test methods address many of the most common occurrences of friction and wear in machinery. During test development, every effort is made to ensure that the tests are reliable and repeatable, and more importantly, to ensure that they add value to wear studies. The five case histories described here illustrate how ASTM wear tests or their variants can be used to solve design problems, production problems, or simply screen candidate materials for general applications. Sometimes application of these laboratory-scale tests can prevent the shutdown of a manufacturing operation that costs thousands of dollars per hour when it is not running. Solving existing or perceived wear problems at the design stage results in significant cost avoidance and, more importantly, it can prevent loss of customers due to failures in service. Service failures not only raise costs, but result in loss of company reputation and business revenues. ASTM wear tests do not address the needs of every tribosystem, but where there is a match with an industrial tribosystem, they should be considered for application because they can

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provide significant savings if used and interpreted properly.

w4x w5x

Acknowledgements The research of the first author was sponsored in part by the U.S. Department of Energy, Office of Transportation Technologies, High Temperature Materials Laboratory User Program, under contract DE-AC05-96OR 22464 with Lockheed Martin Energy Research.

w6x w7x

w8x

w9x

References w1x K.G. Budinski, Use of Wear Tests for Plastics, pres. Am. Chem. Soc., Annual Meeting, Boston, MA, August 1998. w2x ASTM Standard E 691, Practice of conducting and interlaboratory study to determine the precision of test method, ASTM, West Conshohocken, PA, 1994. w3x ASTM Standard G-117, Guide for calculating and reporting mea-

w10x

w11x w12x

sures of precision using data from interlaboratory wear or erosion tests, ASTM, West Conshohocken, PA, 1993. K.G. Budinski, Surface Engineering for Wear Resistance, Prentice Hall, Englewood Cliffs, NJ, 1989, pp. 182–189. ASTM Standard G-99, Test method for wear testing using a pin-ondisk apparatus, ASTM Annual Book of Standards, Vol. 03.02, West Conshohocken, PA, 1995. K.G. Budinski, Scoring of precision spur gears, J. Testing Eval. 22 Ž5. Ž1994. 485–489. ASTM Standard G-98, Test method for galling resistance of materials, ASTM Annual Book of Standards, Vol. 03.02, West Conshohocken, PA, 1991. ASTM Standard G-132, Test method for pin abrasion testing, ASTM Annual Book of Standards, Vol. 03.02, West Conshohocken, PA, 1995. K.G. Budinski, S. Ghosh, Testing solid film lubricants for rotary slitter knives, Lubr. Eng. 51 Ž6. Ž1995. 533–537. ASTM Standard G-83, Test method for wear testing with a crosscylinder apparatus, ASTM Annual Book of Standards, Vol. 03.02, West Conshohocken, PA, 1990. K.G. Budinski, Erosion of 316 stainless steel by dicalcium phosphate, Wear 186–187 Ž1995. 145–149. ASTM Standard G-76, Test method for conducting erosion tests by solid particle impingement using gas jets, ASTM Annual Book of Standards, Vol. 03.02, West Conshohocken, PA, 1995.

ASTM Wear Testing

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