Study on the Influence of Alternating Magnetic Field on Mass Transfer Behavior and Solidification Characteristics of Fe-Cr Alloy Laser Cladding on 45 Steel
摘要
Alternating magnetic field-assisted laser cladding is an effective method to reduce coating defects. However, it is difficult to fully reveal the influence of dynamic magnetic fields on the distribution of elements and the solidification structure merely through characterization experiments. Therefore, in this paper, a three-dimensional numerical model of alternating magnetic field-assisted laser cladding has been established. By analyzing the regulatory behavior of the Lorentz force on the molten pool, the influence of the alternating magnetic field on the mass transfer behavior and solidification characteristics was further revealed. The results show that the magnetic field varying at 50 Hz excites the Lorentz force varying at 100 Hz. Under the influence of the magnetic force, the diffusion ability of Cr element is enhanced. The change in concentration shows that the concentration of Fe element on the cladding layer increased from 84.5 wt.% at 0 mT to 86.3 wt.% at 90 mT. During the solidification stage, with the increase of the magnetic field intensity, the cooling rate increased from 7164 K/s to 8655 K/s, while morphological parameters decreased from 4.69 × 108 s × K/m2 to 3.12 × 108 s × K/m2. Under the alternating magnetic field, the cladding layer exhibits accelerated microstructural transformation and reduced crystal size.