A study on the quality of two-wire tandem submerged arc welds under iso-heat input conditions

Abstract

The influence of the leading and trailing arc welding current on two-wire tandem submerged (SAW-T) arc weld quality was studied at a iso-heat input of 2.5 kJ/ mm. The weld quality includes weld bead dimensions, cooling time from 800 to 500°C in the weld pool, weld bead ferrite phase fraction, and micro-hardness. The cooling time was calculated from the temperature distribution predicted using the numerical model. For a constant heat input, the weld penetration significantly reduced with decreasing leading arc current at a low level of trailing arc current while the final weld penetration was less sensitive to the leading arc current at higher trailing arc current.

Efeito da Velocidade de Soldagem nas Características Geométricas e Microestruturais de Soldas por Arco Submerso em Tandem Arc

“…Comparando as micrografias de cada junta, nota-se que com o acréscimo de velocidade há aumento na quantidade de ferrita acicular, conforme Tabela 8. Dado o efeito positivo que essa microestrutura exerce nas propriedades mecânicas do material, em especial na tenacidade e resistência mecânica, a tendência observada mostra a viabilidade para o emprego de velocidades mais elevadas durante a soldagem de SAW-T. Esse fenômeno ocorre porque velocidade de resfriamento maior atrelados ao aumento da velocidade e, consequente, diminuição de aporte térmico, propiciam a formação de microestruturas aciculares, como a ferrita acicular [1,7,11,25]. Reduções de velocidade de soldagem, por outro lado, promovem maior formação de ferrita de contorno de grão, microestrutura considerada indesejável.…”

“…Em processos tandem arc, cada arame é conectado a uma fonte de energia individual, com controle próprio dos parâmetros de soldagem, de modo que o aporte térmico é fornecido à junta através de múltiplos arcos elétricos. O emprego dessa variante de processo viabiliza a redução do número de passes necessários para a soldagem de chapas mais espessas, reduzindo o tempo dispendido durante a soldagem e eliminando a etapa de limpeza entre passes sobrepostos subsequentes [3,5,7].…”

Modeling and Analysis of Molten Pool Behavior for Submerged Arc Welding Process with Single and Multi-Wire Electrodes

“…The modeling and the molten pool flow analysis of SAW process are mostly conducted by Cho et al [15][16][17][18][19][20][21]. Cho et al [15] conducted molten pool analysis of SAW for single electrode for high-current (I > 500 A) condition with spray metal transfer droplet impingement.…”

“…Moreover, they found that the direction of droplet impingement was very important to expect the welding penetration. Kiran et al [19] analyzed the temperature histories of tandem SAW CFD simulations within the same heat input. They compared cooling times from 800 to 500 C and volume fractions for different welding conditions and they found that molten pool behavior played an important role to decide the volume fraction and micro hardness.…”

Arc characteristics and metal transfer behavior of twin-arc integrated cold wire hybrid welding

“…Besides, the two power supplies can output the reverse-phase pulse current through the pulse synergic control, which 1 realized good control of arcs to decrease the interference between two arcs [6][7][8]. One of the most widely used in the shipbuilding industry was tandem arc welding [9][10][11], which greatly increased the deposition rate as well as the welding speed on the premise of realizing a stable metal transfer. In consideration of further increasing the deposition rate or welding speed by adding the third wire, advanced 3-electrode MAG welding [12,13] and integrated cold wire (ICE TM ) submerged arc welding (SAW) [14] have been successively developed.…”