It’s eating away at everything.” Those words opened the first meeting of the Technology & Maintenance Council’s (TMC) new Corrosion Control Action Committee, this past September in Nashville, TN. Committee Chair Roy Gambrell, director of maintenance for Franklin, KY-based Truck It, Inc., started things out with a critical look at what has been done to address the problem of corrosion:
“We’re used to equipment lasting 10 years,” Gambrell said. “Now we’re lucky if we get seven. The Recommended Practices (RPs) that have been written by TMC Task Forces are not being adhered to.”
THE WORK THUS FAR
Over the past several years, TMC has had various Task Forces and Study Groups working on the corrosion problem, with a reasonably impressive tally of results.
The problem is that Recommended Practices are just that: “recommended.” Despite the fact that these reports and RPs are composed and ratified by fleets, OEMs and component suppliers, TMC has no way of compelling anyone to follow them. Meanwhile, the problem gets worse. Or, as Committee Co-Chair Jerry Thrift says, “We have a more accelerated rate of corrosion.”
What’s different about the new Action Committee (a first of its kind for TMC) is that it is composed of delegates who already belong to existing Study Groups, such as S.1—Electrical and Instruments, S.2—Tire & Wheel, or S.7—Trailers, Bodies and Material Handling. These delegates will, in theory, take information and strategies away from the Action Committee back to their individual Study Groups, where they will actively promote the use of this information among their groups.
It’s a “less talk, more action” approach that might just turn the tide in the fleet industry’s fight against corrosion.
WET AND DRY
Perhaps the most newsworthy item of the meeting was a presentation by Brad Van Riper, VP of research and development for Truck-Lite, Inc., on the new corrosion test being developed by the Society of Automotive Engineers (SAE). The new test, dubbed SAE J2721, promises to be a big improvement over the current industry standard, the ASTM B117 Salt Spray Test, because it includes wet and dry cycles, to simulate the life of a vehicle that is sprayed with wet corrosive agents, then is allowed to dry off, then gets wet again.
According to Van Riper, the ASTM test, that exposes a component to a constant salt mist, has a significant flaw: “The problem is, test results do not correspond to field results,” he explained.
Not only does the SAE test subject the part to realistic wet and dry cycles, it also groups corrosion into different levels: cosmetic corrosion, functional corrosion, and structural corrosion. “We can live with” cosmetic corrosion, Van Riper said, but structural corrosion is “catastrophic.”
Van Riper reported that fleets are already volunteering for field correlation studies to help get the standard established, but he raised a caution flag: “The question is, will the OEMs, component suppliers and fleets use the standards?” he asked.
In a related presentation, Bob Gaylen, president of Tawas, Inc., Noblesville, IN, announced a new testing procedure that could help determine industry standards for corrosion abatement. Called Electrochemical Impedance Spectroscopy (EIS), this nondestructive procedure allows the user to measure corrosion and screen corrosion coating products, and is already in use in the aviation industry.
With EIS, a small electrical charge is “injected” into the electrochemical process (i.e., the corrosion), and the impedance of that charge is then measured. “The resulting spectrum,” Gaylen said, “is like a fingerprint that tells you what is happening in the electrochemical system.”
Gaylen stressed the importance of the accurate measurement of the corrosion that is eating away at a truck’s chassis and components, saying that, “Corrosion is a self-perpetuating process. Corrosion makes material porous, which increases rust development.”
DEFINING THE PROBLEM