MULTILAYER SUBMERGED ARC WELDING METHOD

• Main Authors: ISHIGAMI ATSUSHI, HAYAKAWA NAOYA
• Format: Patent
• Language: English; Japanese
• Published: 26.04.2018
• Subjects: CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

PROBLEM TO BE SOLVED: To provide a multilayer submerged arc welding method for a thick steel plate which can provide a high-quality weld metal suppressing low-pressure cracking and having a favorable bead appearance and a sufficient deposition amount while providing excellent weld metal toughness.SOLUTION: A multilayer submerged arc welding method has a composition where the weld heat input on the first pass when multilayer submerged arc welding is applied to a thick steel plate is 200 kJ/cm or more, and where a flux containing iron powder of 20 to 40% by mass% with a welding metal containing B : 0.0012 to 0.0025%, and Mo : 0.20 to 0.35% by mass%, and weld cracking sensitivity composition Pcm of 0.16 to 0.23 represented by the following expression: Pcm=C + Mn/20 + Si/30 + Cu/20 + Ni/60 + Cr/20 + Mo/15 + V/10 + 5B...(1). In the expression (1), C, Mn, Si, Cu, Ni, Cr, Mo, V, and B are contents (by mass%) of the respective elements, and the content of an element not contained is zero.SELECTED DRAWING: Figure 1 【課題】優れた溶接金属靭性を得ながら、低温割れを抑制し、ビード外観が良好であり、溶着量が十分である、高品質な溶接金属を得ることができる厚鋼板用多層サブマージアーク溶接方法を提供する。【解決手段】厚鋼板に多層サブマージアーク溶接を施す際の１パス目の溶接入熱が２００ｋＪ／ｃｍ以上であり、質量％で、鉄粉を２０〜４０％含有するフラックスを使用し、溶接金属が、質量％で、Ｂ：０．００１２〜０．００２５％、Ｍｏ：０．２０〜０．３５％含有し、以下の式（１）で表される溶接割れ感受性組成Ｐｃｍが０．１６〜０．２３である組成を有する多層サブマージアーク溶接方法。Ｐｃｍ＝Ｃ＋Ｍｎ／２０＋Ｓｉ／３０＋Ｃｕ／２０＋Ｎｉ／６０＋Ｃｒ／２０＋Ｍｏ／１５+Ｖ／１０+５Ｂ ・・・（１）式（１）中、Ｃ、Ｍｎ、Ｓｉ、Ｃｕ、Ｎｉ、Ｃｒ、Ｍｏ、Ｖ、Ｂは各元素の含有量（質量％）であり、含有しない元素の含有量は零とする。【選択図】図１