There is growing interest in the auto industry for a new range of steels which are both thinner and capable of withstanding higher loads than conventional technology.
Developed by SSAB of Sweden, the Docol Roll is a group of steels designed for roll forming applications. The steels are subjected to special heat treatment on a continuous annealing line, giving a material which can be roll formed into narrow radii, according to the company. Typical automotive applications for Docol Roll are safety components such as side impact beams, bumper reinforcements and seat rails.
Improved mechanical properties of the roll grades allows the material to be folded together in a roll forming process using a very small internal radius. The strength of the fusion welded joints for Docol Roll are also higher than the corresponding strength of conventional high 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 products are.
Chua: Advantages include a reduction in the vehicle weight, which in turn improves fuel consumption, lowers CO2 emissions, and contributes to improved crash performance. These benefits can be reached in a cost effective way
AI: What are the different aspects to electro galvanized and hot-dip galvanized surface?
Chua: Electro galvanized and hot dip galvanized surfaces are used for corrosion protection of parts which are exposed to humidity during the lifetime of the car. Docol cold rolled products can be coated with both these methods, but electro galvanizing is used exclusivelyu at the highest strength levels. Both these surfaces gives good corrosion protection and can be painted successfully
AI: How has transport and automotive industries’ demands and needs changed over the years?
Chua: There is much greater emphasis on weight reduction, resulting in lower fuel consumption and CO2 emissions. This is particularly true in Europe, where legislation regarding allowed CO2 emissions continues to be tightened. OEMs will be punished by having to pay fines if the CO2 emissions of new cars do not meet the standards set by governments.
At the same time there is a strong 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 crash tests for European OEMs. The same regulations regarding crash performance is being introduced step by step in every part of the world.
Looking at commercial vehicles such as trucks, there is pressure on OEMs to reduce weight in order to increase the payload. With lighter trucks one can transport more goods without reaching the maximum allowed weight of the vehicles.
AI: In what ways does your product ensure crash safety despite being lightweight?
Chua: The improved strength comes from higher rates of energy absorption during plastic deformation of the component, which in turn leads to improved crash safety. By using high strength steels OEMs can also achieve the crash performance standards with thinner and therefore lighter components.
AI: What makes SSAB stand out from other companies in the automotive and transport industries?
Chua: Through our strong strong focus on making investments for the production of high strength steels. In addition, we offer strong commercial, logistic and technical support focused on high strength steels. There is a special program to help users with Docol cold rolled steels, especially in the ultra high strength area. We provide easy access world wide to trial material for prototyping and pre serial production.
AI: Can Docol Special Steel replace hardened strap?
Chua: I suppose the comparison is between Docol cold rolled steel for cold forming and heat treatable boron steel for hot stamping and press hardening. Strength is built into the delivered coil of Docol special steels. Safety components for vehicles can be produced by cold forming operations at room temperature. This means that conventional cold stamping, roll forming or hydro forming equipment can be used. There is no need for heat treatment, which simplifies production, leading to higher productivity and lower costs. Docol special steel is also easy to weld.