Premature structural and component corrosion of commercial vehicles represents a huge problem for fleet operators that experts in the field say is only getting worse. In a presentation to the organization, Jerry Thrift, chairman of the Future Corrosion Abatement Task Force of the Technology & Maintenance Council, offers a look at corrosion prevention solutions. In the presentation, he does some talking, but really doesn't have to.
The pictures do the talking as he moves through the slides of the PowerPoint arsenal, showing the damage that had been done to components by corrosion: a cab vent window after less than four years, an air spring base after four years, a mirror bracket after three years, brake rotors after five years. There were pictures of a torque arm, a brake chamber spring housing, cracked linings (due to rustjacking), air tanks, trailer cross members. All of them entered the corrosion graveyard long before their time.
How huge a problem? A University of Idaho study two years ago estimated that corrosion caused by anti-icing chemicals costs the US transportation industry $23 billion annually in terms of damage to trucks and highway infrastructure. Corrosion was estimated to cost the Department of Defense at least $20 billion a year, according to a 2001 government-sponsored study. Eight years earlier, the Army had estimated spending over $2 billion a year to mitigate the corrosion of wheeled vehicles, including five-ton trucks. So extensive was the corrosion on some of the trucks that the repair costs were judged to be more than 65% of the average cost of a new vehicle.
The Army defines corrosion as “the unintended destruction or deterioration of a material due to interaction with the environment,” including rusting, pitting, galvanic reaction, calcium or other mineral buildup, degradation due to ultraviolet light exposure, and mold, mildew, or other organic decay. For the truck and trailer industry, the most frequently cited culprits are magnesium chloride and calcium chloride.
“It's definitely a huge issue, and it's a huge issue from several different viewpoints,” says David Alexander, project manager for the University of Idaho's Winter Roads Management Program, which is under contract with the American Trucking Associations (ATA) to study corrosion. “Roads need to be maintained in the wintertime for some sort of mobility level, so there are state departments of transportation involved. And then there are vehicle manufacturers, who work with trucking companies to try to make the vehicles less corrosive. Then there are the haulers and owner-operators.”
Something has to be done, and TMC is doing it.
TMC has approved its Future Truck Corrosion Abatement Position Paper, which is based on the belief that “commercial vehicle users should not need to replace a component over the vehicle's useful life, or the useful life of that component, due to corrosion (including surface corrosion)” and “should not need to perform any maintenance (other than normal, periodic washing) to prevent corrosion.”
TMC's corrosion protection matrix calls for eight years for heavy-duty tractors and trucks, 10 years for light- and medium-duty trucks, 16 years for trailers and converter dollies, 10 years for light-duty truck bodies, and 16 years for medium-duty truck bodies. TMC says corrosion protection for add-on components (liftgates, spare-tire holders, reefers, tool boxes, etc) should be based on the same numbers, and OEMs and suppliers should back up those corrosion performance levels with a 100% parts and labor warranty.
TMC's task force says it is not trying to advise manufacturers on how to produce products (coatings, choice of materials) to comply with that matrix, but TMC's Future Truck Committee believes the position paper “should serve as a road map to assist OEMs and suppliers to meet users' expectations.”
The position paper's conclusions on what is needed:
A clear and specific statement of what users expect regarding corrosion protection.
Standardized laboratory tests that accurately simulate today's real-world environment and (as best as we can) identify what should be anticipated in the future road environment.
Any standardized tests are to have provisions for testing electrical components. Electrical components are to be active during this testing.
Recognition that different zones of a vehicle have different corrosion protection needs. These zones need to be identified and the test requirements for each zone determined. A zone “from the road level to four feet above the road level” should have the greatest corrosion protection (compared to the other zones) and must withstand impact by sand and stones.
Build/engineer components and the vehicle as a whole for the worst-case corrosion scenario. While realizing that eight years' service in northern states is not the same as eight years' service in southern states, we must assume the worst-case scenario and consider the vehicle as being based in a northern-state climate and in a coastal area.
Says Thrift, “The position paper basically says, ‘Hey, I'm tired of replacing these components because they're corroding off my vehicle. Right now, I have to replace mirror brackets and components on my vehicles that I've never had to replace before. What am I doing wrong? The only thing I'm doing wrong is buying your product. I'll give you a little slack in that the environment has changed that your products are working in. But I expect the OEMs to stay on top of this. Have you done anything to your product so I can get a comparable performance that I've gotten in past years?
“But guess what? Maybe it's my fault. I haven't told you what my expectations are. So here it is. I don't expect to have to replace any component on that vehicle due to corrosion: eight years for heavy-duty trucks, 10 years for medium and light, 16 for heavy-duty trailers.' Now, that doesn't mean that all these OEMs are going to be able to meet those expectations. But it tells them, ‘Hey, this is what we're looking for, so you either need to be there or to be working on getting there.’”
Thrift, senior manager of new-product development for Ryder Transportation Services, says OEMs are telling him they are placing a lot more focus on the issue than they had in the past. He saw it first-hand when he visited a truck OEM recently and saw a large collection of corroded parts.
“They told me they had their specifications, but are finding that suppliers weren't meeting their specs, so they were going back to suppliers and saying, ‘You're not even meeting the specs we have today,’” he says. “And then the next problem is, ‘And we're not even sure if that spec is what we need to meet today's environment. That may not be tough enough in today's environment.’”
Thrift says if there is any resistance, it's tied to the additional costs that are involved with putting corrosion-resistant coatings on components.
“There's always a focus on the cost of the final product,” he says. “That adds cost to a lot of components. You add it up collectively and I'm sure it can get to be quite a few dollars. The sophisticated buyers probably will spend extra money because they see the value in it. But will unsophisticated purchasers see the value? Or will they go with a lesser-cost vehicle?
“I'm sympathetic to their selling needs. But at the same time, I guess they need to be sympathetic to ours, too. There's probably some better middle ground than where we are today that suits their needs and our needs. I doubt we'll get to the expectations we've laid out, but I feel they can come a whole lot closer than where they are today.”
TMC's has consulted a number of companies involved in the coating process and in designing vehicles to be less susceptible to corrosion.
Delta Assets, whose current military customers include the US Army, Navy, Marine Corps, and Coast Guard, charges an average of $200 per five-ton truck for the application. Delta uses only Corrosion Prevention Compounds (CPC) that comply with standards set by the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA). The CPCs are military-standard compliant and can be applied over water- and solvent-based paint with no damage. They were chosen after the Army invested $2 million to test and validate 20 CPCs.
Delta uses an Integrated Product Team (IPT) to identify customer-unique requirements, develop tailored program approaches, and assess needs and risks. The team members provide continuous research and product development, and provide a comprehensive approach for analyzing corrosion problems and developing solution alternatives through data collection and analysis, photo documentation, condition assessment and reporting, and return-on-investment (ROI) validation.
As an example of ROI, Delta's Lou Lawrence cited a 5-year-old truck in Hawaii that requires $1050 for parts and corrosion repairs. The ROI is 4:1, based on an average cost of $215 per year for application (depending on the truck configuration). Left untreated, in six years that truck would require approximately $35,000 in repairs, so the ROI is 14:1 (not including downtime revenue loss).
Jet-Hot Coatings, originally developed by NASA and later sold to civilian businesses, produces a ceramic coating that has been used on the space shuttle, carriers, submarines, battleships, destroyers, and jet-engine afterburners.
The ceramic composition serves as an insulating agent and the aluminum composition gives a near metallurgical bond, keeps coating flexible and able to withstand impact, is non-corrosive, and holds up to 1300°F continuous and 1500°F intermittent. Its properties include being conductive, electrochemically active, and sacrificial (can span scrapes and gouges).
In an ASTM B117 test that required 1000 hours in a 5% salt spray, the Jet-Hot coatings showed no corrosion and the test was terminated after 5000 hours without failure. A Car Craft magazine test showed that Jet-Hot coatings provided a 60% heat reduction.
Jet-Hot's Todd Beiswanger said that in truck applications, new and used parts can be coated and warranties are offered. He said the coating is more resistant than chrome, looks attractive, reduces the skin temperature by 25-50%, and increases the life of parts.
Powder coat finishing system
Dave Hammes, senior manager of sales and marketing for Waltco Truck Equipment Co, said Waltco has spent $4 million for powder coating in California and Ohio, using 20,000 sq ft at each location.
He said the powder coat finishing system utilizes the newest technology available for steel-surface preparation and represents a cultural change in the way the product is handled during the manufacturing process. The parts are shot-blasted, and automatic powder application guns deliver an electrostatically charged mist that is applied to three mils and forms a polyester film. It is baked at 400°F for over an hour.
John Repp of Corrpro Companies Inc said service life is being continually extended in Army ground vehicles that operate in harsh environments with a Corrosion Prevention and Control system that includes:
“Vehicle design and construction can promote corrosion through water and poultice entrapment, limited access or no access for supplemental CPC application, and crevices and other close geometries,” he said.
He said procedures and recommendations already exist: SAE J447 (Prevention of Corrosion of Motor Vehicle Body and Chassis), Auto/Steel Partnership (A Guide to Corrosion Protection), and Army TB 43-0213 (Corrosion Prevention and Control).
Overlying themes include: using compatible materials (galvanic), use and location of drain holes (sloping the bottom of the door toward the holes), minimization of crevice areas, and elimination of blind holes/recesses.
He said this is the primary method of corrosion prevention. Materials should be compatible (no galvanic corrosion) and sacrificial (designed to degrade to protect other metals). Pre-treatments improve corrosion resistance and promote coating adhesion. Restoration returns materials to their original condition.
“Coatings are the first defense against corrosion,” he said. “They can provide a barrier or sacrificial protection. They provide a barrier to corrosives like salt and moisture, to abrasion and wear through stone chipping, and they sacrifice themselves to protect substrate, such as galvanizing and aluminizing.”
There are organics: paint systems (spray, powder, e-coat), Chemical Agent Resistant Coating (CARC) systems, and chip and abrasion resistant (high build polyurethane). There are metallics: metallic platings (cadmium, zinc, nickel, etc), hot-dip (galvanizing), and metalizing (zinc, aluminum, and alloys).
He said successful use requires a good process, including surface preparation, application methods and conditions, system controls, and quality assurance testing.
“These are materials applied to further supplement the CPC system: inhibitors, wax preservatives, conversion coatings, and sealants,” he said. They provide additional protection, may require periodic reapplication, and are used during storage or transport.
“It provides for the restoration of the CPC system through the removal of contaminants and corrosion-causing agents and repair and replacement of damaged components,” he said. “It's part of a CPC system, but it is not the primary defense against corrosion. The keys are touchup painting, scheduled and unscheduled maintenance, major component replacement, and remanufacture or rebuild.”
The Holland Group Inc commissioned a team in 2002 to review earlier studies, define specific issues, and make recommendations. It conducted extensive technical and market research, drafted a recommended Holland Paint Performance Standard, evaluated all current Holland coating and painting processes, and identified and tested multiple coating and paint candidates for corrosion and chip resistance, and topcoat and process compatibility.
Holland's Steve Dupay said the primary reasons why coated assets fail prematurely due to corrosion on North American roadways are: poor chip resistance (creep and undercut); hygroscopic (water absorption) through a freeze and thaw cycle; insufficient bond (poor adhesion); poor UV resistance; corrosive anti-ice chemical exposure; and inaccurate qualification tests with methods not reflecting road conditions.
He said simple salt-spray methods do not reflect actual exposure conditions and failure mechanisms such as foreign object damage (chipping), freeze and thaw cycles, fluid resistance, physical destruction, calcium chloride and magnesium chloride, galvanic reaction, and acid rain.
Dupay said there are several paragraphs in the salt-spray test (ASTM B117) that indicate there is no direct correlation between salt spray and real-world performance. He added that the SAE J2334 test, which incorporates a salt-spray cycle along with humidity and drying, has been found to provide correlation to field exposure. He said SAE J2334 more accurately predicts corrosion “creep” and correlates to real-world conditions.
“Indeed, there is historical evidence that materials that perform well in salt-spray testing perform poorly in service, and vice versa,” he said, citing chromate-rich primer with zinc-rich topcoat (tests well, performs poorly in service) and electro-galvanized steel (tests poorly, performs well in service).
He said advanced metal treatments are processes that enable a steel part to “grow” an impervious protective skin. Products to be treated are cleaned and dried. During the application process, the metal dissolves very slightly and the treatment actually plates out onto the clean metal, then is cured to the desired thickness. Black Armour metal treatment reacts with and bonds to substrate.
Dupay said Holland Equipment liftgates have used an earlier-generation version of the same metal treatment for years with “great success.” He said landing gear are: resistant to chipping and corrosion because the treatment compresses, remains flexible, and does not shatter upon impact, prevents under-cutting and corrosion creep, and is resistant to lifting or peel-back; impermeable to water and solvents (10 times more impermeable than a swimming-pool liner); reacts with and mechanically bonds to metal substrate, is not sacrificial, and not a paint; and is unaffected by corrosive anti-ice chemicals.
He said that Holland recommends that TMC establish a “best practice” for corrosion resistance. It would include: a survey of existing product performance (exposure history vs “degree of corrosion” rating, and regional differences); recommended test procedures (gravelometer followed by cyclic corrosion, and accelerated durability/exposure testing); an established correlation between test methods and actual exposure; and a recommended rating scale vs expected performance.
The perfect storm
How did we reach the point where components are corroding at such an alarming rate? Where fleets have to replace parts that they had never before had to replace — fuel tanks, saddle tank bands, lower radiator tubes? Where fleets have to replace safety items such as air tanks?
Thrift calls it “The Perfect Storm.” He says it's a combination of these three things:
The proliferation of more aggressive chemicals being used on the roads.
“We've had sodium chloride for 50 or 60 years. But the two new villains are magnesium chloride and calcium chloride. We don't see this corrosion in the lower states. It's all in the northern climates. If we see it in the lower states, it's on vehicles that run up into the upper states. It's all tied into the deicing of roads. We don't have a problem with that. We need to be safe. But we need OEMs to be more responsive in having protective coatings on vehicles so we don't have to do what we feel as users is unnecessary maintenance. We're replacing structural and non-structural components we never had to in the past because of extreme corrosion.”
Alexander, who has been investigating corrosion as part of a two-year study under the ATA contract, says it's important to take a close look at the state departments of transportation to make sure the chemicals are being applied in the most appropriate manner.
“States generally dictate procedures, but when it comes down to local jurisdictions, it's a little more difficult to regulate,” he says. “Not that they're completely cavalier about it, but there's some good information out there that shows anti-icing techniques reduce the total amount of chemicals used on the roads, and that can have a significant benefit that goes with improved technology — weather forecasting and road sensors, which have come a long way in recent years.
“The general public has gotten to a point these days where they want the roads to be pretty much open all the time. I wouldn't say that applies to the trucking community, but the passenger-car community tends not to want to slow down even when there's ice on the roads. So there's a lot of pressure on the state DOTs to keep the roads open, so they get squeezed from both ends.”
Thrift says he applauds the work done by the ATA's Vic Suski in researching the corrosion issue from the standpoint of the state DOTs, but he doubts that it will change the way chemicals are applied.
“If I put myself in their position, they'd go, ‘Hey, we're making the roads safe, and whatever is happening to your vehicles is your problem,’” he says. “Vic seems to think they'll see our side, but I personally don't think they will. There's already a known additive that can be put in with magnesium chloride that is supposed to inhibit corrosion, but it's a hefty cost to add to the mix, so it doesn't get added.”
The government's attempts to take solvents out of corrosion inhibitors.
“There has been an assault by the government on corrosion-inhibiting protection: Take the lead out, take the solvents out, take the heavy metals out. These were things that were in these coatings to protect the components. So these OEMs and component suppliers are trying to meet the letter of the law, so all of our protective coatings have been getting figuratively and literally watered down.”
Regulations against effluents emitted in the process of cleaning vehicles.
“Speaking for Ryder — and I think this goes for many others — we've had to reduce the frequency of the washing of our equipment. Why? Well, we've got Big Brother watching the effluent coming out. It's not as clean as he likes. We try to use cleaners that are less intrusive on the environment. They might not clean as well as the old ones did, and we might clean vehicles a little less often.
“It doesn't take a leap to say, ‘OK, if we're not cleaning as often, then these salts get on vehicles and stay on vehicles longer and are eating at them before we get a chance to wash them off.’”
Alexander says that based on research he has done during a two-year study under the contract with ATA, there doesn't seem to be “any direct correlation between those that wash and those that don't wash in terms of bad corrosion.”
“It seems like some people say they don't have much corrosion at all; they wash their truck and that's the reason,” he says. “Other people wash their trucks quite frequently and still have a significant corrosion problem.
“One of the things you have to be careful of: If you wash the truck, some of the chemicals can get into the cracks and adhere to the cracks, and it becomes pretty difficult to get the salt out. And even though it's washed and then dried and there seems like there isn't a significant problem anymore, some chemicals can rehydrate and take water from the air and continue to corrode in these crevices.
“Washing is more than a simple spray on the exterior. You really have to get into cracks and crevices with a power washer and clear it out. Staying away from acid will reduce the corrosion because a higher pH will increase corrosion and accelerate it, particularly when there's salt in the same solution. You want to stay away from harsh abrasives — anything that's going to scratch the surface, but you want to get in there and be diligent about cleaning. Otherwise, you're wasting your time.”
Alexander says that if components are experiencing severe corrosion after only two or three years, the issue probably is one of manufacturing, rather than chemicals on the road.
“It's probably a situation where parts didn't get the right quality control or the proper coating, or there was a defect in the material from the suppliers,” he says. “That definitely happens. A big part of the issue is getting quality assurance from the manufacturers that the materials used and the coating and painting protection are adequate and perform to the proper standards.”
Suski says he has suggested to Thrift that the task force adopt as a TMC recommended practice the Army's corrosion-rating system, so that fleets have a standard way to refer to the severity of their problem.
“Right now, it's subjective,” Suski says.
According to CC Technologies' Web site at CorrosionCost.com, “There is a definite disparity in the application of effective corrosion control among industrial sectors and among entities within an industrial sector. When available corrosion control technology is not applied, opportunities for corrosion cost savings will be missed. There is often a disparity between those who control corrosion costs and those who incur the costs. This can lead to a mentality of ‘build it cheaper and fix it later’, and a disregard for life-cycle costs. The situation is further exacerbated when the builder is not made responsible for the ‘fix-it’ costs.”
In an article by Joe J Payer and Ronald Latanision, one of the preventive strategies recommended was to “change policies, regulations, standards, and management practices to increase corrosion savings through sound corrosion management.”
A few of the suggestions:
“Compile and disseminate the state of the art information through federal government agencies such as DOT, DOD, and DOE, as well as the state and local government. These agencies regulate, finance, and provide information relevant to corrosion design and maintenance for structures in both the public and the private sector, and spend billions of dollars each year on structures that are subject to corrosion. With this type of action, these agencies will realize the savings and the improved services that result from designing for corrosion and managing it better.
“Change tax policies to eliminate bias against sound corrosion control practices. Current tax policies treat investment and maintenance costs differently. Investment costs are written off over a period of time while maintenance expenditures are recognized as costs in the year that they are incurred. The intricacies of tax policies are rather complex; however, it is important to point out that the current tax policies bias decisions regarding corrosion control. Being able to expense maintenance expenditures while having to depreciate investment expenditures over many years wastes the nation's resources and at the same time imposes a large amount of inconvenience on the public due to premature corrosion-induced deterioration. The tax system needs to change in order to encourage higher investments in improving the corrosion performance of structures and other capital items.
“Critically review government regulations for their impact on corrosion costs. A myriad of regulations at the federal, state, and local levels affect corrosion design and management. The regulations are intended to help the public; however, due to a lack of consideration of important factors regarding corrosion design and management, undesirable consequences may result. The impact of regulations on corrosion control practices and the costs of corrosion are often overlooked. With the added perspective of corrosion costs, the true cost/benefit balance of a regulation can be significantly changed. Regulations need to be reviewed and analyzed to uncover any and all implications for corrosion management. Those regulations that are outdated or skewed because they were formulated without considering their implications for corrosion, need to be reconsidered. For example, the Environmental Protection Agency (EPA) has universally banned the use of chromates because of their threat to the environment and human health. However, chromates are also known to be among the most effective corrosion inhibitors. In fact, in some applications there is no close alternative. Rather than an outright ban of these compounds (no risk approach), the regulation should allow examination of specific cases in a benefit-risk framework. There are likely to be some applications where the use of chromates results in greater public benefits than its replacement. In these applications, the use can be controlled so that little or none of the compounds result in environmental discharge or human exposure.”
Alexander says there are no easy solutions. It's a complex issue that needs to continue to be studied.
“There are many compounding factors that result in many unique situations,” he says. “More and more data will bring us closer to understanding the significant factors. Understanding leads to prevention.”