BUTTING AND WELDING METHOD

To provide a butting and welding method by which plates different in thickness can be butted and welded with satisfactory welding strength.SOLUTION: Provided is a butting and welding method, in which a first plate (W1) and a second plate (W2) thicker than the first plate (W1) are butted and welded. The method comprises an L-shape bending step (ST1) in which, before the first plate (W1) and the second plate (W2) are butted (ST2), the first plate (W1) is bent into an L-shape, and thereby a bent end part (W1b), which is bent from the body (W1a) of the first plate (W1), is formed in the first plate (W1). In the L-shaped bending step (ST1), after the formation of the bent end part (W1b), a length (t3) from a bend initializing point (W1c), located on the boundary between the body (W1a) of the first plate and the bent end part (W1b), to the leading end (W1d) of the bent end part (W1b) is substantially identical to the thickness (t2) of the second plate (W2).SELECTED DRAWING: Figure 3 【課題】厚みの異なる板同士を良好な溶接強度で突合せ溶接することができるの突合せ溶接方法の提供。【解決手段】第１の板（Ｗ１）と、第１の板（Ｗ１）よりも厚い第２の板（Ｗ２）とを、突き合わせて溶接する突合せ溶接方法である。第１の板（Ｗ１）と第２の板（Ｗ２）とを突き合わせる（ＳＴ２）前に、第１の板（Ｗ１）をＬ字状に折り曲げ加工して、第１の板（Ｗ１）において第１の板（Ｗ１）の本体（Ｗ１ａ）から折り曲がった折り曲げ端部（Ｗ１ｂ）を形成するＬ字折り曲げ加工工程（ＳＴ１）を備える。Ｌ字折り曲げ加工工程（ＳＴ１）では、折り曲げ端部（Ｗ１ｂ）を形成した後において、第１の板の本体（Ｗ１ａ）と折り曲げ端部（Ｗ１ｂ）との境界に位置する折り曲げ開始点（Ｗ１ｃ）から折り曲げ端部（Ｗ１ｂ）の先端（Ｗ１ｄ）までの長さ（ｔ３）が、第２の板（Ｗ２）の厚み（ｔ２）と実質的に同じである。【選択図】図３