Numeric simulation and experimental study in magnetic field-assisted laser scanning welding of T2 red copper

Abstract

To address the challenges of low energy coupling efficiency and poor process stability in the laser welding of T2 red copper, this study establishes a thermal-fluid-coupled three-dimensional numerical model; and we conduct experimental tests to investigate the effects of different magnetic field strengths on laser scanning welding of T2 red copper. The results indicate a high degree of conformity between the simulated calculations and experimental tests in terms of the cross-sectional fusion morphology. As the magnetic field strength increases from 0 to 160 mT, the lowest and highest temperatures, melt width, and melt depth of the weld pool initially exhibit an initially increasing trend followed by a decreasing trend. At a magnetic field strength of 120 mT, these parameters peak at 1383 K, 4810 K, 2.388, and 1.753 mm, representing improvements of 2.44 %, 58.75 %, and 1.68 %, respectively, compared with those without an applied magnetic field. However, the maximum flow velocity within the weld pool exhibits a trend of initially decreasing and subsequently increasing, reaching a minimum value of 0.4102 m/s at a magnetic field strength of 120 mT, representing a 12.76 % reduction compared with that without an applied magnetic field. As the magnetic field strength increases, the surface morphology of the weld seam initially improves and then deteriorates. In addition, the grain structure within the weld zone first becomes finer and coarser. When the magnetic field strength reaches 120 mT, the surface-forming quality of the weld seam improves; the internal grain structure of the weld zone becomes finer; and the hardness, tensile strength, and electrical conductivity of the weld joint reach their respective maximum values of 47.13 HV, 270 MPa, and 78.24 mS/m. This represents significant improvements of 18.45 %, 56.07 %, and 25.2 %, respectively, compared to those without an applied magnetic field. Under a steady magnetic field. the effective thermal input of the laser energy to the base material is enhanced, thereby improving the stability of the weld pool during the welding process. This enhancement leads to improved welding quality, yielding new insights and theoretical foundations for the laser welding of T2 red copper.