Vehicle construction is changing rapidly. To borrow from a Bob Dylan lyric, the times are "a-changin'." These words, first sung some 45 years ago, still ring true today. Back then, your baby sat beside you while you were behind the wheel of your Ford F-100, which was made of conventional steel. Today, you may be humming a different tune. You may have no particular place to go in your 2009 F-150, but a lot more features from which to choose, including safety, comfort, and infotainment enhancements. While we can't put a price on safety, and consumers certainly value the high-tech capabilities of today's vehicles, they do add a significant amount of weight to a vehicle. This combination doesn't mesh so well with today's need to maximize fuel economy and reduce emissions. Can you imagine what one of those classics would weigh with all of today's add-ons? My estimate is somewhere around 6,000 pounds.
So how are Ford and other leading manufacturers able to provide customers with all of those must-have features while achieving weight savings, improved vehicle crash worthiness, fuel economy, and reduced total greenhouse gas emissions? The answer is advanced high-strength steel (AHSS).
More than half of the vehicles sold in the United States today currently contain some amount of AHSS. This includes some other familiar vehicles, such as the Chevrolet Traverse and the Chrysler Town and Country, which have above-average utilization of AHSS in their construction. The 2009 Ford F-150, for example, has HSS roof bows and rear roof structure, as well as ultra high-strength steel (UHSS) roof rails and a passenger safety cage. The cage is said to be 75 percent stronger, yet only seven percent heavier than its predecessor. While domestic vehicles are making strides, European cars currently lead the way for incorporating AHSS in door and side structure assemblies. The primary motivator here is meeting strict European Union side-impact requirements.
This increasing trend of bulking up the amount of AHSS is predicted to increase 10 percent each year, according to a recent Automotive Applications Council of the American Iron and Steel Institute's Steel Market Development Institute study on AHSS. The increasing trend isn't just a trend. Rather, it's the industry's response to meeting the Bush Administration's mandated increase in the Corporate Average Fuel Economy (CAF?) standard to 37.5 fleet miles-per-gallon average. Now that the Obama Administration has further increased the CAF? standard to 43 miles per gallon, the use of AHSS will continue to increase and may become a standard. According to Ducker Worldwide Research, automakers will replace over 650 pounds of mild and high strength steels with 350 pounds of AHSS, aluminium, magnesium, and composites to reach this fleet mile-per-gallon mandate.
Improper Clamping Compromises Safety
No one would dispute the fact that you have to possess a great deal of knowledge to estimate and repair a collision-damaged vehicle. Understanding the type of material and its properties being used in vehicle construction is critical. This should be identified before starting an estimate — let alone the collision repair process — to avoid potential safety issues. Improper welding or even attaching pinch weld clamps without adequate knowledge of a vehicle's construction can irreparably damage the metallurgy or assembly integrity. This can lead to some startling consequences that estimators and repairers need to be aware of before the process begins. These welding techniques, which may seem commonplace, can actually weaken structures. They can also change the impact absorption and airbag deployment timing, in turn creating a potentially dangerous situation in the unfortunate event of another collision.
If you were to use pinch weld clamps to secure a Porsche Cayenne, for example, then you would compromise the adhesive bond between the inner and outer rocker panel assembly, thus weakening the structure. The only way to rectify the situation would be to completely replace the assembly, which would be quite expensive. Even if you don't repair Cayennes on a routine basis, other vehicle models will likely cross your path more than once, like the new Volkswagen Passat. This vehicle's center pillar is laser-welded and must be attached with adhesive bonding material if replaced in the collision repair environment. Volkswagen cautions that if the replacement panel is welded, then the structural integrity may be compromised. Again, this would potentially expose the driver to serious injury in the event of another collision.
Look Before You Heat
Applying heat to straighten metal panels can be complicated because recommendations for heating AHSS are incredibly specific, and the metals are extremely heat-sensitive. According to vehicle manufacturers and steel companies, heating should never be used to straighten AHSS. The extreme temperature required to straighten damaged steel not only limits the extent to which some new types of steel can be straightened, but it also causes degradation and embrittlement to structural components such as rocker panels and pillars. Even though you will not be able to discern a difference in the appearance of the metal, make no mistake; it is there. Remember that the goal in a collision repair is not merely limited to returning a part to its original physical shape and appearance. You should ensure that the part maintains its original, pre-crash properties to protect the safety of the vehicle's passengers, as well.
Instructions, Not "Recommendations"
Keep in mind that it's no longer safe to rely on the once tried-and-true method of treating a type of steel you can't identify as HSS. It is not optional to understand each manufacturer's recommendation or repair instructions; it is critical. A recent discussion with a collision repair representative from Porsche revealed invaluable advice that should be applied to any vehicle manufacturer. He stressed that because recommendations can be ignored, Porsche does not have recommendations. Instead it has repair instructions that identify one proper way to repair the vehicle.
These days, you have to be a bit of a chemist even when it comes to a seemingly routine job like refinishing a hood, which can even become dangerous if you don't possess certain requisite knowledge. For example, let's imagine that a technician is repairing a vehicle with an aluminum hood. The repair technician grinds the finish down with a dual-action sander and vacuum. This sounds harmless, right? Well, think again. If the fine aluminum dust created during the sanding process comes in contact with moisture in the storage canister of the vacuum, then hydrogen gas is formed and an intense explosion can occur. Although this scenario sounds like an urban myth best reserved for Discovery Channel's "MythBusters" TV show, it really can happen. In October 2003, the Hayes-Lemmerz plant in Huntington, Ind., which was machining aluminum auto wheels, experienced an explosion so severe it the Chemical Safety and Hazard Investigation Board (CSB) launched an investigation. The CSB news release indicated that aluminum dust caused a primary explosion near a chip melting furnace, followed by a secondary blast in dust collection equipment, killing one employee and injuring two others.
To prevent similar incidents and possible explosions, collision shops and insurance appraisers must initially determine the exact type of material they are estimating to repair, what comprises the material, and the potential combustibility of the components. Along the same lines, it is essential to remember that combustible dust accumulations outside of process equipment provide the fuel for potentially catastrophic secondary dust explosions where ignition sources are present. Proper dust collection equipment design and compliance with electrical classification requirements are a must.
But who is responsible for identifying the materials in the first place? Quite frankly, it is incumbent on both the insurance appraiser and the collision repairer to possess a thorough understanding of the material construction of the vehicle for which repairs are estimated. Everyone needs to be on the same page as far as the proper repair instructions are concerned. If an appraiser doesn't understand the vehicle's material composition, then he or she may unknowingly recommend an improper repair procedure that could lead to supplementation and repair delays if the repairer objects.
However, if the improper repair is performed according to the estimate, without interjection from the repairer, then both parties share the responsibility of dealing with the consequences of not being informed. That said, the collision repairer shoulders direct responsibility and needs to know — without fail — the correct repair and waste disposal procedures when accepting the repair job. Understanding the vehicle's composition is imperative. This vital knowledge will enable the industry as a whole and repair shops to save time and money — by performing the proper repair the first time. More importantly, it can also save lives.
Greg Horn is vice president of industry relations at Mitchell International. He may be reached at greg.horn@mitchell.com.
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