Page 1

WEAR NEWS Volume 7, Number 3 Spring 2009

Wear of Materials 2009 The biannual Wear of Materials Conference (WOM) was held at the Golden Nugget Hotel in Las Vegas, NV (USA) on April 19 – 22. There were about 300 delegates from 31 countries in attendance and about 190 papers were presented. The session topics were about the same as previous WOM conferences: Wear of Polymers Thin Film Coating Sliding Wear of Metals Erosion Biotribology Wear Test Methods Abrasive Wear Modeling Case Studies Lubrication (only 5 papers) Ceramic Tribosystems Skin friction seemed to be a new subject of interest. Ultrahigh molecular weight polyethylene is still being studied for orthopedic joint replacement and fretting wear and fretting corrosion appeared to be making a comeback in research activity. About 70 delegates presented their work as posters and awards were presented to two. The conference organizers also offered an “experimental” session on practical wear problem solving. Attendees were asked to submit their “problems” to a panel of experts consisting of four experienced (well-worn) tribologists. The session was lively, but did not have the attendance of a keynote.

There were four invited plenary Speakers over the four-day program:

1. Wear Mechanisms and Mitigation Strategies in Microsystems – Mike Dugger, Sandia National Labs, USA.

2. Effect of Material Wear on Hydro

turbine Performance – Bill Bruninger, Manager, Hoover Dam, USA.

3. Aspects of Tribological Coating

Design and Selection – Alan Matthews, University of Shefield, UK

4. Surface Engineering of Advanced

Ceramics for Friction and Wear Control – Karl-Heinz Zum Ghar, University of Karlstade, Germany.

Mike Dugger described how vapor phase lubrication is used to allow practical application of MEMs devices; Bill Bruninger described the building and operation of Hoover Dam (WOM Inc. sponsored a tour of the nearby dam on the last day of the conference). Alan Matthews described how coatings with layers engineered to carry loads allow PVD coatings to work where they may not have worked in the past. He also promoted the use of the hardness/elastic modulus ratio as the material parameter that controls wear “the use of the hardness parameter in the Archard equation is bordering on nonsense.” Karl-Heinz Zum Ghar described how the strategic use of surface texturing, surface finishing, and lubrication allows

Page 2

the successful use of ceramic/ceramic tribosystems. Finally, Peter Blau presented appropriate limericks and comments to close the conference luncheon. The following are some “findings of use to me” acquired at WOM. There were concurrent sessions so they only reflect the papers that I attended. Nuggets from WOM 2009:

o Hoover Dam earns $500 M + per year for its hydropower.

o The USA tried to build a bridge over Hoover Dam but to date, has failed.

o The dry-sand rubber abrasive test can be used as a sliding wear test by replaced the rubber wheel with a WC/Co wheel.

o The ball-cratering test is still used to assess abrasion resistance, but the normal force must be 5N to prevent grit rolling rather than the desired scratching mode of material removal.

o The ASTM G181 scratch test should use a normal force of 60N.

o A 25% WC cermet with a 1% C, 10% V matrix is good for gouging abrasion

o Plasma electrolytic oxidation (PEO) is becoming popular for hardcoating aluminum and magnesium.

o Vista Engineering has a nanocrystalline diamond coating suitable for coating complex WC/Co cutting tools

o Bronze/steel couples in aircraft landing gears are being replaced by “altered” titanium couples

o Balinite C coating works in fuel injectors o Coatings for wear should have high

hardness and low elastic modulus o BN is the lubricant of choice for super-

plastic forming of A1 and Mg auto body panels

o 30% of the cost of a mining operation is lost metal (due to wear) cost

o Nanofretting is material damage due to relative movements in the nanometer range

o The hardness of sand is 11 GPa (TiCN is 35 GPa).

o DLC is biocompatible o A 55% WC, 45% NiCrB hardfacing has

great abrasion resistance o Successful use of vapor phase lubrication

on silicon usually requires atomic layer deposition of a precursor

o Current research on cutting tools ignores edge radius and fabrication burrs. They think a ground edge is atomically sharp

o Niobium is being used to replace vanadium in tool steels

o Scuffing is still being studied (scoring is not a preferred term).

o The biotribologists are trying to improve the poor wear characteristics of UHMWPE with molecular modification and all sorts of fillers (Zr, nanoclays, coral, etc.).

The venue for the 2009 Wear of Material Conference was excellent. The Golden Nugget Casino Convention Center was the conference location and sessions were lively and well attended in spite of being less than 100 m from the pool, restaurants, and gaming tables. The next WOM will be in Philadelphia in 2011. The organizers and delegates are to be congratulated for another successful conference. The only thing that needed improvement was industrial participation. There was very little; most papers were from academic and government entities.

ASTM G2 Wear and Erosion Activities

The spring ’09 meeting of the ASTM G2 Committee on Wear and Erosion was held at the Marriott Waterside Hotel in Norfolk, VA, USA. We met at committee week and the committees meeting there including the D2 committee on lubricants and fuels. Falex Corporation hosted a hospitality suite where they displayed some of their oil-testing equipment. The following is a summary of the actions taken by the various wear and erosion subcommittees.

Page 3

Abrasive Wear – The meeting was chaired by Steve Shaffer (Batelle). Most of the subcommittee’s meeting was focused on their “Flagship” test, the dry-sand rubber wheel test, ASTM G 65. ASTM has rigorous rules on the use of metric on English units in standards. There was considerable discussion on how to resolve the use of mixed units in the standard, but the important issue addressed was the rubber wheel crisis. The only identified supplier of the rubber wheels has been unable to supply them to users because their rubber supplier ceased to be their rubber supplier. They are evaluating a new supplier, but it may be a year or years until the new supplier is qualified. To compound the problem, hardfacing companies and coatings developers have been migrating to heterogeneous materials containing carbide particles in the millimeter size range which can destroy a new rubber wheel in one test. So the wear surfaces of interest are becoming extremely destructive to the rubber wheels and there are no rubber wheels available and when they become available, the cost may be $800 to $,1000/wheel (per Falex). The subcommittee decided to hold a workshop at the next meeting in November to discuss these issues and the future of the test. Some specific interim actions agreed to were:

1. Ken Budinski (Bud Labs) will draft an addition to the scope statement cautioning test users on the effect of testing materials with large (500 µm +) hard phases with large (500 µm +) free spaces of matrix between particles or hard/softer regions.

2. Andy Peilps (U of D Research Institute) will develop a strawman tackiness test for the wheel rubber.

3. Rob Sailor (U of D Research Institute) will draft a wheel dressing procedure using a die grinder and cemented carbide burr.

4. Workshop talks were identified.

The other abrasion issues discussed included the ASTM G171 scratch test, the polishing pad test, and the ink abrasion test. The G171 was balloted and reapproved, but Peter Blau (ORNL) will revise it to include a lower scratching speed and a new procedure for scratch measurement. The polishing pad test still shows as a work item, but there has been no activity toward a standard. The G56 abrasion by ink impregnated fabric test is subject to reballot and Steve Shaffer will contact Ray Bayer to determine if it is still used and if any upgrades are necessary. Erosion Activities – The meeting was chaired by Andy Phelps. He reported that Chair Paul Swanson is resigning and that he would be willing to take Paul’s place. (His assumption of the chair was subsequently approved by the Chairman and Executive Committee.) There was discussion of the ongoing review of the G32 cavitation test. Action on this standard was deferred to Task Group Chair, Frank Heymann. In addition, Frank will investigate updates to the stationary specimen cavitation test. It was reported that ASTM G 73 rain erosion test is now subject to reapproval. Andy Phelps reported that changes may be needed to use physical damage as opposed to mass change as the test metric. Non-abrasive Wear Activities – The meeting was chaired by subcommittee co-chair, Mike Anderson (Falex). Scott Hummel (Lafayette University) reported that he has interlaboratory tests in process for the recently approval galling standard: G 196. Mike Anderson will investigate transferring the G119 standard on wear /corrosion synergism to the erosion subcommittee. Peter Blau (ORNL) reported receiving negatives on the reapproval of the G 181 standard for the friction of piston ring materials. Peter will also

Page 4

investigate transferring this test to the ASTM G05 Friction Subcommittee. Peter hads eight labs lined up to perform interlaboratory tests on the use of the “friction” test as a piston ring wear test. Ken Budinski (Bud Labs) reported that there were persuasive negatives and comments on the last ballot of the proposed fretting test standard. The ballot was withdrawn and revised to address all negatives and comments. The test will be reballoted before the next meeting and persons interested in participating in interlaboratory tests should contact kenbudinski@hotmail.com. Greg Dalton (Tribsys) reported that he is drafting a new galling test entitled “Standard Test Method for Adhesive Wear Properties of Materials by Twist Compression Test.” Peter Blau is also drafting a new galling test that is performed at elevated temperatures. Computerization Activities – Subcommittee Chair, Greg Dalton, reported that the planned workshop on “Data Acquisition” will be deferred. Friction Activities – Subcommittee Chair reported that the recent ballot on “A Guide for the Use of Friction Energy Dissipation to Assess Frictional Characteristics of a Tribosystem” was withdrawn because of persuasive negatives/comments. It was revised to accommodate the ballot results and it will be reballoted in the summer. The G115 standard on measuring and reporting friction is up for reapproval. Chair Ken Budinski reported that he has been working with Staff Manager, Kate McClung, in updating the standard to include other ASTM standards that measure friction. Kate will send additional standards to Ken for review. The following shows the status of current friction standards. STANDARD DESCRIPTION 6/09 STATUS

G115 Guide for Measuring and Reporting Friction Coefficients

In revision for reapproval

G143 (09) Test Method for Measurement of Web/Roller Friction

No action required

G164 (04) Test Method for Determination of Surface Lubrication on Flexible Webs

No action required

G181 (04) Practice for Conducting

Friction Tests of Piston Rings and Cylinder Liner Material Under Lubricated Conditions

No action required

G182 (06) Test method for Breakaway Friction of Rolling Element Bearings

No action required

G194 (08) Test method for

Measuring Rolling Friction Characteistics of a Spherical Shape on a Flat, Horizontal Surface

No action required

Work Item

Use of Friction Energy Dissipation to Assess Friction Characteristics

Draft in ballot

Terminology Activites – Subcommittee Chair, Peter Blau, discussed negatives on recent ballot items (galling, wear, abrasion) and reported that the definition for “rolling friction” was approved. The terms that failed to pass in ballot were discussed and these agreed to – revised definitions will be reballoted along with new terms such as “abradant,” Irodant,” and “scratch.” Miscellany – G2 Committee Officers: The G2 Nominating Committee reported the following nominations for the terms that begin in 2010:

Page 5

Chairman – Scott Hummel Vice Chairman – Greg Dalton Secretary – Mike Anderson G2 Future Meetings: November 2 & 3, 2009 Battelle Memorial Institute Columbus, OH (includes workshop on 11/2) May 21 – 23, 2010 Ballys, Las Vagas, NV (with STLE) December 9 & 10, 2010 Hyatt Regency Jacksonville, FL (with D2) June 20 & 21, 2011 Baltimore, MD (with D2) December 4 & 5, 2011 New Orleans, LA (with D2) Dry Sand Rubber Wheel Abrasion Test Workshop An all-day workshop will be held on Monday, November 2 at Battalle in Columbus, OH to discuss and resolve issues with the G65 test method. The program as of June 30 was: Mike Anderson (Falex) – Machine demo

Brian Merkel (Nanodyne) – Rubber wheel issues Ken Budinski (Bud Labs) – Use of different rubbers Rob Sailor (U of D RI) – Wheel dressing and specimen directionality

Andy Phelps (U of D Research Institute) – Rubber tack test/sand morphology Note: The attached tribology events calender is complements of Peter Blau, Oak Ridge National Laboratory

Editorial – Use of synthetic oils in automobile engines in question

I recently purchased a US-made small truck with a 4-cylinder engine. After driving the vehicle for 3,000 miles, I had the dealer drain the manufacturer-supplied engine oil and replace it with a top-selling brand of synthetic oil and new filter. At 8,000 miles, I decided to check the oil for cleanliness. I found it loaded with metallic particles with sizes in the range of 10 to 100 µm. I performed the same cleanliness test on an oil sample taken from the vehicles’ first oil change and found almost no metallic particles in this oil and the metallic particles that were present were below 10 µm in size. The particle intensity (size times number) in the synthetic oil was 40 times that in the first oil change. I repeated the test three different days with similar results. This was not a designed experiment, but it was incontrovertible evidence to me that synthetic oil can destroy an engine and I will never use it again in an automobile. A race car driver later told me that the oil that I used had ZDDP removed about two years ago and racers stopped using it. The ZDDP removal may have contributed to my negative results. I welcome reader comments the on use of synthetic oils in automobiles. Ken Budinski

Page 6

NOTE: Wear News is the informal account of

ASTM G2 Committee activities and related

tribological activities. Article contributions by others are encouraged.

Send them and other inquiries to: Ken Budinski Bud Labs 904 Ridge Road West Rochester, NY 14615 (USA)

Page 8