Estudo da soldabilidade a ponto por resistência entre os aços 22MnB5 e DP800

• Ano de defesa: 2015
• Autor(a) principal: Gabriela Pereira de Miranda
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: 22MnB5; Soldagem a ponto por resistência; DP800; Engenharia metalúrgica
• Link de acesso: http://hdl.handle.net/1843/BUBD-A4TJEK

This study aimed to evaluate the resistance spot weldability of 22MnB5 and DP800 steels, both 1.8 mm thick. Before welding, 22MnB5 sheet samples were heated in a furnace, simulating the process of hot stamping. The objective was to set of welding parameters appropriate for this type of welded joint, which has been progressively used in automotive assembly, due to the growing use of parts manufactured from 22MnB5 steel, subjected to hot stamping process. The interaction between welding time (9/2/9/2/9 cycles) and the electrode force (5.0 kN) allowed the best welding range. Mechanical properties of all welded joints were evaluated using cross tensile and lap shear test samples. It was noticed that the welded joint made from the welding time with multiple pulses (9/2/2/9/2 cycles) and the electrode force of 5.0 kN, achieved the best results in shear test. However, the force of 6.5 kN resulted in higher values for the cross tensile test. Furthermore, it was observed that interfacial fracture occurred only in shear tensile test, when using the minimum welding current. The button fractures were observed for the other currents, both shear tensile as cross tensile. Nevertheless, all the conditions evaluated were approved in both tests, obtaining the minimum failure load which ensures the qualities of a welded joint.