Over 170 professionals from more than 40 companies and academic institutions participated in the International Seminar on the Application of High Strength Steels in the Lightweight Design of Commercial Vehicles that was held in São Paulo in early July 2013.
A partnership between SSAB, Rossetti and CBMM resulted in a more efficient mining truck
Organized by Companhia Brasileira de Metalurgia e Mineração (CBMM) together with SAE-Brasil, the meeting was dedicated to the debate around the use of alternative materials in the lightweight design of commercial vehicles. The discussions focused on fulfilling three basic industry goals: reduce weight, lower costs and improve overall performance.
Ten papers were presented, including case studies, corporate projects and academic research, all of which addressed the use of high strength steels in the manufacture of commercial vehicles.
According to Marcos Stuart, CBMM's director of technology, participants identified three common goals: reduce vehicle weight, realize concomitant cost savings and achieve enhanced performance as a result of the application of high strength steels.
To reach these objectives, Stuart described three major challenges. For him, achieving significant reductions in emissions is essential. He also expressed the need for the industry to reconcile mechanical forming and strength in these enhanced materials. In his opinion, the best product for manufacturing commercial vehicles continues to be steel, but producers should not limit themselves to conventional steels when alternatives provide significant advantages.
For the third challenge, Stuart recommended the adoption of "simplicity" in the production process, remembering that with good design it is possible to reduce the weight of structures and simultaneously guarantee increased component strength. "The choice of materials is extremely important for this," he emphasized.
A result along these lines appears to have been achieved in a project presented by PCP Steel that was developed in partnership with Ruukki of Finland. Applied in trucks used in the demanding transportation of enormous logs in the south of the country, high strength steel led to the reduction of 55% in the weight of the structures, representing a drop of over 150 kilograms in the weight of the haul trailer.
According to Vagner Araújo of PCP, the high strength steel used in that project had strength levels on the order of 1500 megapascals, which led to gains in weight reduction and consequent savings in cargo transport.
The same type of benefit was reported in a CBMM project carried out in partnership with chassis manufacturer Rossetti and Swedish steelmaker SSAB, a global supplier of high strength steel. The mining truck project employed Hardox and Domex steels for components with up to 700 megapascals in strength, which allowed for a 25% weight reduction in the bucket. Use of these high strength steels resulted in 2.2% savings in total transportation costs, a reduction of 3.7% in diesel consumption and a 3% decrease in carbon dioxide emissions. Forty linear meters of welds were also eliminated, representing significant labor and other cost savings.
CBMM's director of technology explained that for him, 700 megapascal steels present considerable strength and provide good properties related to cold forming, cutting and welding. He also remarked that Brazil is the leader in Latin America in the commercial vehicle sector, but that there is a need for more investment in truck safety. A seminar presentation specifically addressed the use of high strength steel in Volvo trucks and its impact on cabin crash tests.
Stuart lamented that Brazil still imports truck motors and engine blocks, noting that the stage is set for the development of this sector in the country. Two types of technology were presented that could optimize the lightweight design of commercial vehicles - tailored blanks and laser welding. These techniques make it possible to create components made of steel sheets that have different thicknesses and different grades with strength levels ranging as widely as 200 megapascals to 900 megapascals. These sheets have the capacity to progressively absorb energy, which is fundamental for crash safety.