By changing over to a different material, an Italian manufacturer of side collision protection beams reduced the rejection rate from 40 percent to zero!
“Our new Dogal 800 DPX steel can withstand advanced forming,” declares Johan Broback, Product Manager for Dogal at SSAB Tunnplåt. “The product is an ultra-high strength, hot-dip galvanised steel that has the formability necessary for producing parts of very complicated shape.”
Advanced high strength steels are becoming increasingly common in new cars. New steel grades enable carmakers to save weight, while also providing the cars with better protection against corrosion and improved comfort.
But the automotive industry is also striving to achieve higher quality. During the past ten years, the industry has taken giant strides towards improved anti-corrosion treatment by using a growing proportion of zinc coated material in the bodies.
60 percent of new steels
“GM cars, for instance, now contain an average of 10–20 percent of extra-high strength, hot-dip galvanised steels,” says Johan Broback. “But by 2010, this figure is expected to rise to 40–60 percent.”
In Japan, the automotive industry uses 13 percent of extra-high strength, hot-dip galvanised steels in the bodies, but this figure is expected to rise to 45 percent within five years.
While the automotive industry wants increasing amounts of high strength and anti-corrosion treated steels, new cars are becoming increasingly technologically advanced. The designs of various parts demand steels with tailored properties.
Combine different properties
“Our DP steels cover a large proportion of the needs that are characteristic for the automotive industry,” says Johan Broback. “The special properties of DP steels combine good formability with strength.”
SSAB Tunnplåt manufactures these steels in a special process that yields what is known as dualphase steels. The new product known as Dogal 800 DPX is subjected to special heat treatment that improves the formability further.
“In practical terms, this means that the steel can withstand tight bending radii during forming,” explains Johan Broback. “Moreover, Dogal 800 DPX has excellent reversing bendability, which means that it can be bent back and forth without cracking.”
Saves weight
SSAB Tunnplåt has developed steels of increasing strength and now has a leading position on the market. The steels enable weight to be saved, since thinner materials can be used.
“High strength steels can often be used in production after minor adjustments to the tools and the production line,” considers Johan Broback. “Most of the changes relate to adjustments to suit the springback of the high strength steels after forming, and also to using the right tool steels.”
New opportunities
Dogal 800 DPX is a product that offers entirely new opportunities to stylists and designers. Exciting new forms can be created, while opportunities are also opened for producing finished parts in one piece. A great deal can be saved by eliminating the need for joining smaller parts into a finished product.
SSAB Tunnplåt supports customers with a wide range of information on the properties of advanced high strength steels and the opportunities they offer.
Customer requirements
“Development work today involves regular communication with the customer,” says Johan Broback. “We are devoting continual work to ensuring that our products conform to the requirement specifications of our customers. So it is particularly exciting to present Dogal 800 DPX which offers more than today’s standards specify.”
Text: Håkan Johansson News Magazine No 2, 2004