The good news is thanks to the use of advanced high-strength steels vehicles are safer than ever in severe crashes.
The bad news is that in the worst crashes these same ultra-strong steels can make it difficult to extricate survivors from a crushed vehicle.
Traditional “Jaws of Life” hydraulic cutters simply cannot shear through the new steel alloys used for the body structures of a growing number of cars and trucks. And new rescue tools capable of cutting through the high-tech steels cost about $5,000 each, says Ron Moore, a battalion chief and training officer for the McKinney, TX, fire department.
In addition to his duties as a full-time fire chief, Moore travels around the country training rescue workers on extrication techniques.
Vehicles traditionally have been comprised of about 60% steel by weight, but the types of steel that go into today's vehicles are changing rapidly as auto makers rush to reduce weight and improve safety, according to the American Iron and Steel Institute.
In 2008, about 23% of the body of a typical U.S.-built vehicle was comprised of advanced high-strength steels. The body shell of the upcoming budget-minded Chevy Cruze is 64% advanced high-strength steels, Moore says.
Ron Krupitzer, vice president of automotive applications at the Steel Market Development Institute, says AHSS are used for a variety of applications within a vehicle's structure.
Some alloys, such as those used for front rails, are designed to crush and absorb crash energy. Others, like those used in B-pillars and door beams, are designed to resist intrusion forces and transmit energy rather than collapse into the passenger space.
The latter type of advanced steels frequently, but not always, are alloyed with the element boron to create their extraordinary metallurgical strength. And it is these so-called “boron steels” that are becoming famous for both saving lives and being problematic for rescue workers.
Fire Chief Moore knows both sides.
“I have seen real-world crashes (where) the vehicles have gone through some significant impact rollover or whatever and the occupants are outside exchanging information with the cops when we pull up. Years ago, they would have been mangled in the vehicle,” he says.
But Moore says he also is spending an increasing amount of time teaching rescue workers new “work around” techniques to cope with B-pillars that can't be cut.
Traditionally, when a car was involved in a severe broadside collision, trapping an occupant, the strategy was to open up the side of the vehicle like a metal can, Moore says.
“Our No.1 default strategy was to sever the B-pillar at the top, make a couple hinge cuts at the rocker and lay the thing down and open up the whole side of the vehicle,” he says.
“Now I'm saying, ‘If you can't do that, we have pushing equipment that can get inside the vehicle and simply push from the B pillar on one side to the other or simply push the metal back to where it belongs, away from the patient.’”
The steel industry's Krupitzer says the difficulty in extracting people from vehicles “is a bit of a tradeoff. But I think we would agree it's better to have more people alive.”
AISI, State Farm Insurance and other organizations are helping Moore with his training efforts, assisting with research on identifying and cutting advanced steels.