Special steels delivered with strength built into the coil

Thereis growing interest in the auto industry for a new range of steels which areboth thinner and capable of withstanding higher loads than conventionaltechnology.

Developed by SSAB of Sweden, the Docol Roll isa group of steels de­signed for roll forming applications. The steels aresubjected to special heat treatment on a continuous annealing line, giving amaterial which can be roll formed into narrow radii, according to the company.  Typical automotive applications for Docol Rollare safety components such as side impact beams, bumper reinforcements and seatrails.

Improved mechanical properties of the rollgrades allows the material to be folded together in a roll forming pro­cessusing a very small internal radius. The strength of the fusion welded jointsfor Docol Roll are also higher than the corresponding strength of conventionalhigh strength steels.

Automotive Industries(AI) asked from Kris Chua, Marketing and Communications Specialist, S.E Asia,India & Pacific, what the benefits of using of Docol cold rolled productsare.

Chua: Advantagesinclude a reduction in the vehicle weight, which in turn improves fuelconsumption, lowers CO₂ emissions, and contributes to improved crash performance. Thesebenefits can be reached in a cost effective way

AI: What are the different aspects to electrogalvanized and hot-dip galvanized surface?

Chua: Electro galvanized and hot dip galvanized surfaces are used for corrosionprotection of parts which are exposed to humidity during the lifetime of thecar. Docol cold rolled products can be coated with both these methods, but electrogalvanizing is used exclusivelyu at the highest strength levels. Both thesesurfaces gives good corrosion protection and can be painted successfully

AI: How has transport and automotive industries’ demandsand needs changed over the years?

Chua: There is much greater emphasis on weight reduction, resulting in lowerfuel consumption and CO₂ emissions. This is particularly true inEurope, where legislation regarding allowed CO₂ emissions continuesto be tightened. OEMs will be punished by having to pay fines if the CO₂emissions of new cars do not meet the standards set by governments.

At the same time there is astrong focus on improving the protection of passengers in the event of a crash.Using high strength steel like Docol is a must when undergoing Euro NCAP crashtests for European OEMs. The same regulations regarding crash performance isbeing introduced step by step in every part of the world.

Looking at commercial vehiclessuch as trucks, there is pressure on OEMs to reduce weight in order to increasethe payload. With lighter trucks one can transport more goods without reachingthe maximum allowed weight of the vehicles.

AI: In what ways does your product ensure crash safetydespite being lightweight?

Chua: The improved strength comes from higher rates of energy absorption duringplastic deformation of the component, which in turn leads to improved crashsafety. By using high strength steels OEMs can also achieve the crashperformance standards with thinner and therefore lighter components.

AI: What makes SSAB stand out from other companies in the automotiveand transport industries?

Chua: Through our strong strong focus on making investments for the productionof high strength steels. In addition, we offer strong commercial, logistic andtechnical support focused on high strength steels. There is a special programto help users with Docol cold rolled steels, especially in the ultra highstrength area. We provide easy access world wide to trial material forprototyping and pre serial production.

AI: Can Docol Special Steel replace hardened strap?

Chua: I suppose the comparison is between Docol cold rolled steel for coldforming and heat treatable boron steel for hot stamping and press hardening.Strength is built into the delivered coil of Docol special steels. Safetycomponents for vehicles can be produced by cold forming operations at roomtemperature. This means that conventional cold stamping, roll forming or hydroforming equipment can be used. There is no need for heat treatment, whichsimplifies production, leading to higher productivity and lower costs.  Docol special steel is also easy to weld.