Microstructure and mechanical properties of adjustable-ring-mode laser welded and hot-stamped Al–Si coated boron steel joints

• DOI: 10.1016/j.jmrt.2023.12.018
• Publication Date: 2023-12-07T08:07:46Z
• Authors: Hyun-Uk Jun; Jae-Deuk Kim; Jooyong Cheon; Jaehun Kim; Yeong-Do Park; Yang-Do Kim; Changwook Ji
• Keywords: ARM laser; Mining engineering. Metallurgy; Al–Si coated; TN1-997; Hot-stamped; Mechanical properties; Ring beam; Microstructure

The microstructure and mechanical properties of adjustable-ring-mode (ARM) laser-welded, hot-stamped 22MnB5 steel joints were analyzed compared with those Al–Si coated 22MnB5. Al segregation into the fusion zone (FZ) was suppressed by a ring beam introduced via ring-beam-mode (RBM) dual-beam-mode (DBM) laser welding. Dilution coating in FZ induced α-ferrite formation during hot stamping. After stamping, fraction decreased (from 23 vol% to 4.27 vol%) more than that center-beam-mode (CBM) welded owing beam. Electron backscattered diffraction analysis indicated distribution high-density uniform geometrically necessary dislocations, which caused coordinated deformation martensite grains, RBM DBM FZs. average microhardness tailor-welded blank (TWB) ∼30–40 HV lower base metal (480 HV) CBM reduced 295 because large amount ductile α-ferrite. tensile strength elongation TWB joint ∼989 MPa 1.1 %, respectively, significantly (1245 1.96 respectively) (1321 2.12 respectively). Finally, sheets subjected ARM welding without removing layer evaluate effect on suppression joints.