To prevent delayed fracture of a weld zone, when a fastening member is resistance-welded to an ultra high strength steel sheet having a tensile strength of 1.8Gpa or higher.SOLUTION: A steel sheet 1 is strengthened so that a tensile strength becomes 1.8 Gpa or higher by hot pressing the steel sheet 1. A ring-shaped region 7 where a fastening member 4 of the hot-pressed steel sheet 1 is to be welded is irradiated with a laser beam 8 having a low energy density, to thereby perform laser annealing. A tensile strength of the region 7 is lowered by laser annealing. Thereafter, the fastening member 4 is resistance-welded to the laser-annealed region.SELECTED DRAWING: Figure 1

    【課題】引張強度が1.8Gpa以上という超高強度鋼板に締結部材を抵抗溶接する際に、溶接部の遅れ破壊を防止する。【解決手段】鋼板1を熱間プレスすることにより、鋼板1を引張強度が1.8GPa以上となるように強化する。熱間プレスされた鋼板1の締結部材4を溶接すべきリング状の領域7に低エネルギー密度のレーザービーム8を照射することによりレーザーアニールを行う。このレーザーアニールにより、領域7の引張強度を低下させる。その後、レーザーアニールが施された領域に締結部材4を抵抗溶接する。【選択図】図1


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    Title :

    MANUFACTURING METHOD OF PRESS MOLDED PRODUCT


    Additional title:

    プレス成形品の製造方法


    Contributors:

    Publication date :

    2020-10-22


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    Japanese


    Classification :

    IPC:    B21D WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL , Bearbeiten oder Verarbeiten von Blechen, Metallrohren, -stangen oder -profilen ohne wesentliches Abtragen des Werkstoffs / C21D Veränderung der physikalischen Struktur von Eisenmetallen , MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS / B23K Löten , SOLDERING OR UNSOLDERING / B62D MOTOR VEHICLES , Motorfahrzeuge



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