WEAR NEWSVolume 7, Number 4 Fall 2009

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World Tribology Congress (WTC)Kyoto, Japan

The World Tribology Congress, which is sponsored by many tribology societies, held their fourth conference in Kyoto, Japan from September 5 to September 11. It is probably the largest tribology event around. It is held every four years and previous congresses were in London, Vienna, and Washington, DC. This meeting had an attendance of about 1300 delegates from more than 40 countries. I estimated about 20 Americans present. Japanese delegates predominated. The meeting was held in the Kyoto Conference Center, which was the site where the 1997 Kyoto Accord was reached – the save our world plan for the environment.

The conference was opened by a keynote speaker from Washington, Christopher Flavin, an environmental consultant. He set the “green tribology” tone of the event. According to him, the world has only five years to get their act together. After that, the global warming trend will feed on itself. The polar caps will melt and forests will arise to feed the warming trend even further. He advocated wind and solar energy to replace fossil fuel.

There were many other talks on how to do green tribology. Tribologists are being called upon to reduce friction and wear of everything because both friction and wear are key energy factors – 20% of an automobile engine’s energy is spent overcoming friction, etc.

Almost immediately after the keynote lecture, we were surprised by an opening ceremony arranged by Peter Jost of “Jost Report” fame. He is the chair of the WTC and he and conference chair, Professor Kimura, persuaded His Royal Highness, Prince Asihieto, to open the conference with remarks about the seriousness of our environmental “assignment.” We must contribute

to the reduction of carbon emissions effort. His English was perfect and his remarks appropriate.

The first day was dedicated only to keynote lectures. Five other keynotes followed the opening ceremony.

The second keynote speaker was Masamoto Takenato, the CEO of R&D at Toyota. He described their new entry into the “Smart Car” market, the IQ. It is the world’s smallest four-seat automobile; it is less than 3 meters long. He described some of their recent tribology innovations like low viscosity oil, DLC on clutch plates, and solving brush wear on fuel pump motors. Toyota visualizes a diverse fleet to 2030 of battery cars for around town and internal combustion alone for long hauls.

The third keynote was a Nobel Laurate from Tokyo University who talked about his problems in convincing the world of the existence of neutrinos, whatever they are.

Mark Robbins of the US was the next keynote and he talked about friction fundamentals and use of molecular dynamics in friction studies.

The fifth keynote was on biotribology and how it is going to give all of us a second fifty years. He did not say if we get a new mate for these second fifty; it sounded like only new joints and organ regeneration with stem cells.

The next keynote was on the status of tribology in China. An area needing tribology attention is their railroads. They need more and better ones. They carry 24% of the world’s passenger miles on 6% of the world’s rails. They wear out 630,000 wheels per year. They use 6,000 tons/year of copper contacts for electric trains. They also plan to land a person on the moon by 2017 so they need some tribology innovations in space hardware. They will have 85 million cars on the road by 2010, so there will be some associated tribology problems.

The last keynote was presented by Koji Kato and he discussed green tribology which includes sustainable life cycles on equipment, self-healing wear scars, water + 1% oil as a lubricant, and lubricant-on-demand machines.

The technical sessions went from 8:40 AM to 11:50 AM with fifteen minute talks, 5-minute discussion. There were 922 of these talks, and needless to say, I missed a few. They covered the usual range of tribology subjects: additives, friction, surface engineering, biotribology, greases, bearings, machinery, etc. Testing of wear surfaces seemed to be the hottest topic after “green tribology.” Everybody is using lasers to put dimples and grooves in counterface bodies. There are countless options for these patterns and most papers were about the right pattern for a particular application. Noticeably absent were sessions on abrasion and erosion. There were many more than the usual number on friction. It has become a concern because of energy conservation initiatives. Friction in any tribosystem results in lost energy, energy not used to perform function. My talk was on ASTM’s new rolling friction measurement standard, G 194, but it did not have “keynote” status. One student appeared awake for a part of it.

The following are some “nuggets” that I took away from WTC IV:

Nuclear energy is irrelevant, only 6% in 2030

Hydro will only account for 3% of energy supply in 2030

Wind and solar will supply most energy by 2030

The Chinese will be the world leaders in photovoltaics (PV’s)

A type of glycerol must be added to petroleum lubricants to allow their use on DLC-coated tribocomponents

Molybdenum trioxide powder is a good high temperature lubricant

The coefficient of friction of cartilage vs bone is 0.001

Stem cells will repair a drilled hole in cartilage

MRI + MATLAB can be used to calculate in vivo wear rates of cartilage

20 to 50% of lubricants used end up in the environment

Evaporation is a problem with the new 5-W20 oils

Water is the enemy of synthetic lubricants Chewing gum is polyisobutylene (as in

STP) Hg, Pb, Sn, W, Cu, Ni will be gone by

2060 Vegetable oils need oxidation resistance

before their use can be proliferated 60% of mechanical energy is friction loss 50% of the vehicles in the US are SUV’s or

light trucks with an average weight of 3,800 lb

Namba style walking (to keep kimono perfect) reduces the tendency for slipping

UHMWPE filled with copper chelate is the newest counterface for prostheses

Discrete element modeling (DEM) has the power to simulate everything, even silly things

Overall, this was the best organized conference I have attended. There was a staff of three people in each room to handle the AV system; there were people at desks everywhere to answer questions. There was always free coffee at the exhibit and free lunches were available every day provided by industrial sponsors. Of course, you had to listen to some company promo during lunch, but I learned something from each one that I attended.

The next WTC will be in Turin, Italy in four years and Peter Jost will probably try and get the Pope to open it. Peter and the organizing committee did a great job on this conference; his committee, Professor Kimira, and the Japan Society of Tribologists are to be congratulated.

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Fall 2009 ASTM Meeting

The ASTM Committee on Wear and Erosion had their fall ’09 at Battelle Memorial Institute in Columbus, Ohio, USA on November 2 and 3. The meeting started with an afternoon workshop on the dry sand rubber wheel test, ASTM G65. The purpose of the workshop was to discuss and address problems/concerns with the tests that have arisen since the last time that the standard was reviewed and reapproved. The biggest “problem” was the loss of the sole supplier of the rubber wheels needed to perform the test. The supplier decided to not make the rubber wheels anymore because of availability problems for ingredients needed to make the 60 Shore A chlorobutyl rubber tired wheels.

The workshop was attended by about 20 people and presentations were made by Troy LeValley from Falex Corp., Brian Merkle from Nanodyne, Ken Budinski from Bud Labs, and Andy Phelps from UDRL.

Troy LeValley reported that the immediate problem of no-rubber has been solved. Akron Rubber Development Lab has acquired the molds from Falex and they have successfully made new wheels for several months. The wheels are available from Falex for about $1,000 each. Some of the action items from the workshop are below:

The sole supplier of 50 to 70 AFS test sand stopped “making” the sand. A nearby company started to become a new supplier and the previous supplier, US Silica, in Ottowa, Illinois is back in business.

The “new” sand appears to be somewhat rougher than the old sand.

Falex is getting high volume losses (the spec calls for 34 to 35 mm3 and they are getting about 40 with the new chlorobutyl wheels.

Falex is offering to send a specimen load cell around to users to check specimen-to-wheel loading.

Nanodyne believes that the sand flow rate range is too large and needs to be narrowed to 300 to 350 g/min.

A Dremel grinder with a 80 grit SiC sanding drum can be used to dress rubber wheels.

Alternate wheel rubbers (SBR, Neoprene, Neoprene/EPDM) do not produce the same wear results as chlorobutyl wheel (CBR)

CBR has higher abradant-to-rubber friction than Neoprenes and SBR

Wear ratios may be the better test metric The use of alternate rubbers may be

possible using the wear ratio metric. The AFS sand (50/70) analysis should be

40% max on the 40 screen, 47% min on the 50 screen, 2 % on pan.

The test specimen shall butt up against the front on the holder.

The standard needs an applicability statement.

A new round robin is advisable after the test is modified with updates.

The workshop showed that there is strong interest in the test and that all problems/concerns need to be addressed in the reapproval process. The workshop results will be forwarded to Mike Anderson (Falex) for implementation.

Abrasion Activities:

Chair, Steve Shaffer (Battelle), asked for action items from the groups concerning the updating and reballoting of the dry sand rubber wheel test and other abrasion standards. The G56 test on abrasiveness of printer ribbons has been reviewed by Steve and it will be reballoted. Peter Blau (ORNL) submitted a revised report on the G171 scratch test and the commercial listing of a machine was deleted. Peter is researching different ways to measure scratch widths for determination of scratch hardness.

John Fildes made a presentation on abrasion work being performed at the Institute of Tribological

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Coatings. They propose using an “Improved Ball Cratering Micro Abrasion Method.” They use a 4-ball test with the center ball made from Neoprene (12.5 mm dia.). Dry abrasive is retained in the system and each test yields essentially 3 ball crater scars (2.75 to 12.5 lb load, 1/2 ball, 60 rpm, 70 A ball, 340 g normal force to face of specimen).

Erosion Activities:

Andy Phelps, Chair, has resigned from the Erosion Subcommittee for health reasons. Scott Hummel (Lafayette College) chaired the meeting and reported there is no ballot activity in their standards. Jeff Smith (consultant) talked to the group about the need for updating the solid particle and droplet erosion tests for use as coatings and at elevated temperatures and proposed a future workshop on particle and droplet erosion.

Frank Heymann submitted a detailed report of activities in the G32 vibratory cavitation tests. Subgroups have been established for liquid conditioning, surface preparation, simplification, and reference materials. There has been reportable progress in most of these subgroup activities.

Non Abrasive Wear Activities:

Chair Nick Randall (CSM) reported that the crossed cylinder test, G83, has been withdrawn because it has not been reviewed. ASTM G98 galling test has been reapproved. Scott Hummel (Lafayette College) is doing a round robin test with 6 labs to obtain recent data on reproducibility.

A new piston ring wear test is in development at Oak Ridge National Lab and the use of the reciprocating test to measure piston ring friction has been moved to the friction subcommittee. A new standard for a 3 pin-on-disk test is being developed by Mike Anderson (Falex). Scott Hummel is conducting interlaboratory tests on the new G196 galling test.

Three negatives were discussed on the new fretting test standard and all issues will be addressed in a joint subcommittee and main ballot. Greg Dalton (Tribsys) has drafted a tentative twist-compression test standard. The next step is to obtain task group review before balloting.

Peter Blau made a presentation on a new test method for high temperature galling of metals using 3 pins on flat specimen configuration (36o

reversals, can go to 900oC – has a compression load cell of 5,000 lb, 2,000 lb normal force). He presented experimental data on a variety of material couples.

Friction Activities:

Chair Ken Budinski (Bud Labs) presented negatives on two standards for discussion: On the Guide for Measuring and Reporting Friction Coefficients, G115. The negative requested that the standard caution users on the importance of entry edge geometry, surface preparation, and method of cleaning. Appropriate changes were made and the standard was sent for concurrent sub and main ballot.

The other negatives were obtained as a ballot of “Guide for Determining Friction Energy Dissipation in Reciprocating Tribosystems.” One negative was withdrawn after word changes in a section. The other negative was withdrawn after the applicability of the standard was demonstrated. It will be moved to committee ballot.

John Fildes (Tribology Institute) will supply information on the use of rms techniques for calculating dissipated energy.

Computerization Activities:

Chair Greg Dalton reported that the Guide for Developing and Selecting Wear Tests” ASTM G190 is approved, but the other standards in this area are not subject to review at this time. A new work item is to develop a standard on machine

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condition monitoring. The name of the subcommittee was changed to “Data Acquisition in Tribosystems”.

Terminology Activities:

Chair Peter Blau resolved negatives on a variety of terms and the following will now be defined in the G 40:

Rolling friction forceGallingWear

These terms will be balloted in the future:

Abrandant, erodent, abrasion

Abrasion was defined as “see abrasive wear;” wear resistant, wear resistance, and tribocorrosion will be balloted in the Spring of 2010.

Miscellany:

Future Workshop/Technical Activities:

Jeff Smith – will work on an erosion workshop.

Nick Randall will try to get Greg Sawyer to give the ASTM group a tour of University of Florida wear lab at the Jacksonville meeting.

Future Meetings:

May 19 & 20, 2010 -- Bally’s Los Vegas (with STLE)

December 8 & 9, 2010 -- Hyatt Regency, Jacksonville (with D2)

May 19 & 20, 2011 -- CSM, Boston

December – 4 – 8, Sheraton, New Orleans (with D2)

Awards:

Steve Shaffer was presented the Frank Heymann award for continuing service to the G2 committee.

Scott Hummel was presented the Frank Brantigam award for outstanding work in standards development at the task group level.

Green Technology:

In keeping with the urging of the World Tribology Congress, we need to consider environmental effects in tribotesting. This photo shows the “waste” produced by one ASTM G65 abrasion test

(40 lbs of sand) compared to the waste from the G174 abrasion test –one used abrasive tape loop that can be reused in the shop for polishing or deburring. Maybe some G65 users should consider making the switch.

Fretting Workshop:

ASTM Committees E08 on mechanical property testing and F04 on medical devices held a workshop in conjunction with their Fall meeting in Atlanta (November 8 – 13) on:

“Fretting Fatigue of Metallic Medical Devices and Materials”

There were nine papers and the workshop was attended by about 60 people. Most of the papers dealt with fretting of stents. The following are the

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titles of the papers presented followed by my “micro” abstracts:

Corrosion and Fracture of Overlapped Stents in Swine Models – (They put stents in live pigs and documented failures.)

Human Retrievals: Tissure-Stent Interfaces and Biomechanical Fractures – (They retrieved stents from corpses; dissolved the arteries with NaOH and use SEMs to document fractures, fretting, and wear.)

FDA Perspective on Fretting Corrosion Assessment of Vascular Stents – (they have lengthy testing protocols and do not approve materials for stents, only devices in finished form)

Fretting Corrosion of Overlapped Stents – (They used potentiodynamic polarization tests on stents to identify materials/couples that showed transpassive corrosion in a PBS test solution.)

Fretting Fatigue in Endovascular Stent Grafts: Observations and Considerations for Device Testing and Analysis – (They showed how stents are being applied to more kinds of artery problems, and that fretting is likely in the many overlapped areas. They also said that fretting corrosion/wear can occur from rubbing contact with calcified vessels and arteries.)

Fretting of Nitinol Surfaces – (They used electronic corrosion tests before and after wear to evaluate the corrosion resistance of Nitinol and concluded that it does not wear and does not degrade from fretting.)

Application of Low Plasticity Burnishing (LPB) to Improve the Fretting Fatigue performance of Ti 6A14V Femoral Hip Stents – (They developed an WC ball burnishing device that imparts a compressive stress on rubbing surfaces to prevent initiation of fatigue cracks in hip prosthesis.)

Standard Test for Damage to Contacting Solid Surfaces Under Fretting Conditions –

(I described our G2 fretting test that is in ballot)

Activities of EO8 on Standardization and Terminology in Fretting and Fretting Fatigue – (The workshop chair, Richard Neu (Georgia Tech) described the “Guide” that they are developing to help select a fretting test).

Summary – This workshop was a wonderful opportunity for the six ASTM committees that are concerned with fretting damage to come together and discuss standards. The D2 Committee was not represented, but their “fretting test” is really a lubricant test. The electrical contact people and the bearing people seem satisfied with the tests that they now have.

As an unbiased observer, I walked away with the feeling that stent fatigue is a very serious problem that is getting almost no funding for fundamental research. One doctor in attendance reported that she found a broken stent in one of her patients and he was dead within a year after detection.

The “stent people” appear to rely on SEM images to assess wear and fretting in overlapped stents. They call metal-to-metal wear “abrasion” and I never recognized fretting wear or corrosion in any of the many SEM’s micrographs that were shown. I think that they are getting plain ordinary metal-to-metal wear and not fretting wear or corrosion. One speaker claimed fretting damage can occur at slip amplitudes of 0.1 nm. I think that they need to make measurement of slip amplitude priority one.

In any case, the organizers are to be commended for this very fruitful gathering of the fatigue and medical devices groups. There will be a follow-up symposium on fretting in China in April 2010

Product Liability Workshop:

Also in Atlanta, there was a workshop on “ASTM Standards on Trial: The Impact of the Absence of Standards on Product Liability Litigation in a

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Mock Trial” sponsored by Committee F08 on forensics.

This was a wonderful demonstration of the importance of ASTM standards and the importance of their “thoroughness.” They conducted a mock trial of a girl hurt in a hockey accident. They had real lawyers, a judge, jury, expert witnesses. It was a very enlightening experience. Our standards need to be good; we need to be meticulous on the scope and precautions in use. The lawyers will uncover any weaknesses in the document.

Tribology Events Calendar:

The attached events calendar was prepared by Dr. Peter Blau of Oak Ridge National Lab. Thank you, Peter.

NOTE: Wear News is the informal account of selected tribology events and the activities of the ASTM G2 Committee on Wear and Erosion.

Contributed tribology articles are welcome.

Send them and other inquiries to:

Ken BudinskiBud Labs904 Ridge Road WestRochester, NY 14615 (USA)

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