Effect of YAG Laser Cutting Pulse Energy on Stretch flangeability of TRIP Steel Sheet with Bainitic Ferrite Matrix
抄録
In the present work, effect of YAG laser cutting pulse energy on stretch-flangeability in 0.2C-1.5Si-1.5Mn ultra high-strength TRIP-aided sheet steel with bainitic ferrite matrix (TBF steel) which were austempered at 375 or 450℃ was investigated for automotive applications. The tensile strength (TS) of TBF steel austempered at 375℃ was higher than that of TBF steel austempered at 450℃. The press formability of laser cut surface layer was investigated by hole-expanding test. On the other hand, the stretch-flangeability (λ) of TBF steel in the case of hole-punching austempered at 375℃ was larger than that of TBF steel austempered at 450℃. Further, the stretch-flangeability austempered at 375℃ in the case of laser cutting at 4J/P was larger that that of 450℃. The strength-stretch-flangeability balance (TS×λ) of TBF steel austempered at 375℃ became maximum by laser cutting at 4J/P. The good stretch-flangeability was completed by laser cutting at 4J/P in TBF steel austempered at 375℃. The stretch-flangeability of laser cut hole depended on surface roughness in TBF steel austempered at 375℃. When a suitable condition of laser cutting is selected, the stretch-flangeability of laser cut hole is better than that of punched hole.
TRIP型ベイニティックフェライト鋼板の伸びフランジ性に及ぼすYAGレーザ切断パルスエネルギーの影響
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KJ00004767866
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