| Abstract Scope |
In the international market, new safety and fuel economy regulations have intensified pressure on the automotive industry to rethink the applications of alternative materials and seek the opportunities that new steel grades have to offer. However, the final cost of vehicles in Brazil, due to the use of materials that would allow the trends presented above to be met, has been a major barrier. For this reason, it’s important to optimize the materials and methods of their application. Thus, this project is part of one or another larger project whose main focus is to propose the replacement of imported AHSS class DP800 steel with similar national ones with corresponding properties of mechanical resistance, formability, weldability and impact absorption capacity. In the specific case of this work, the proposal is to make a change in the resistance spot welding equipment so that it is capable of applying the force necessary to weld these new AHSS. The equipment we have is medium frequency direct current (MFDC) composed of a transformer (Bosch PSG 3100), a controller (Bosch PSI6100.100L) and a water-cooled pneumatic welding clamp (pressures between 660 and 3700 N). As the national DP steels analyzed all have resistance limits above 380Mpa, the applied force must be 4500N in accordance with ISO 18278-2:2016. As our equipment does not apply this force, the proposal of this work was to resize the pneumatic actuator and increase the structural rigidity of the equipment to support the new force. With the replacement of the pneumatic actuator with an 80mm sleeve for another 125mm, the maximum force increased to 8000N. Once the necessary adaptations and structural reinforcements have been carried out, the equipment is capable of welding both national and imported AHSS. |