The effects of YAG laser welding conditions on mechanical properties of ultrahigh strength 0.23C-0.19Si-1.29Mn-0.013P-0.001S-0.052Al-0.024Ti-0.21Cr-0.003B (mass%) hot-formed (22MnB5) steel were investigated. Tensile tests have been conducted for laser butt welded joints obtained from the combination of the same steel. The tensile properties were affected by the welding speed and the pulse energy. The joint penetration was obtained by using the energy of 15.2 J/pulse (mean power: 685 W, pulse frequency: 45Hz, pulse width: 3.8ms) and the welding speed of 250 mm/min. It was concluded that the YAG laser weldability of the 22MnB5 steel was ascribed to the weld joint formation. The joint strength decreased by about 500 MPa, compared with the tensile strength of base material, and welded efficiency was 75%, because of notch effect and crack initiation at the laser weld of welded heat affected zone (HAZ) and the base material.
自動車用0.23%Cホットスタンプ材のYAGレーザ溶接性
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