WELD METAL FOR HIGH ENERGY DENSITY BEAM WELDED JOINT, HIGH ENERGY DENSITY BEAM WELDED JOINT, WELD STRUCTURE, AND STEEL PIPE

To provide a weld metal for high energy density beam welded joint that is excellent in toughness.SOLUTION: Adopt a weld metal that is a weld metal used at a high energy density beam welded joint formed by irradiating a high energy density beam to the part to be welded of a steel material, contains C: 0.02 to 0.12%, Si: 0.20 to 0.60%, Mn: 0.8 to 2.3%, S: 0.0035 to 0.0080%, O: 0.0003 to 0.0020%, and, furthermore, in which P, Ti, Al, Ca and N are restricted respectively, the balance consists of iron and impurities, the MnS generation index value is over 0.175, the hardenability index Ceq is 0.35 to 0.60, acid sulfide particles of 0.1 to 2.0 μm in circle equivalent diameter are present in the weld metal at a number density of 3×105 to 1×106 pieces/mm3, and, of the particles, particles having a MnS ratio of 5 to 40% are 45% or more of the total number of acid sulfide particles.SELECTED DRAWING: None 【課題】靱性に優れた高エネルギー密度ビーム溶接継手の溶接金属を提供する。【解決手段】鋼材の被溶接部に高エネルギー密度ビームを照射することによって形成された高エネルギー密度ビーム溶接継手における溶接金属であって、Ｃ：０．０２〜０．１２％、Ｓｉ：０．２０〜０．６０％、Ｍｎ：０．８〜２．３％、Ｓ：０．００３５〜０．００８０％、Ｏ：０．０００３〜０．００２０％を含有し、更に、Ｐ、Ｔｉ、Ａｌ、Ｃａ、Ｎをそれぞれ制限し、残部が鉄および不純物からなり、ＭｎＳ生成指標値が０．１７５超であり、焼入れ性指標Ｃｅｑが０．３５〜０．６０であり、溶接金属中に円相当径で０．１〜２．０μｍの酸硫化物粒子が個数密度３×１０５〜１×１０６個／ｍｍ３で存在し、この粒子のうち、ＭｎＳ割合が５〜４０％の粒子が全酸硫化物粒子数の４５％以上である溶接金属を採用する。【選択図】なし