Butt welding joint using high-energy density beam

A welding joint formed by a high energy density beam, the welding joint comprising:

• a pair of steel materials;
• and
• a welding metal that is located at a butt welding portion between the pair of steel materials,
• wherein the pair of steel materials have a C content in a range of 0.01 to 0.08 mass %,
• wherein the welding metal has a C content in a range of 0.01 to 0.08 mass %, a Si content in a range of 0.05 to 0.76 mass %, a Mn content in a range of 0.8 to 2.5 mass %, a Cu content in a range of 0.0 to 5.0 mass %, a Ni content in a range of 0.5 to 7.8 mass %, a Cr content in a range of 0.0 to 6.0 mass %, and a Mo content in a range of 0.0 to 2.0 mass %,
• wherein the amounts of C, Si, Mn, Cu, Ni, Cr and Mo in the welding metal further satisfy the following formula (a),
• Ms(° C.)=371−353C−22Si−24.3Mn−7.7Cu−17.3Ni−17.7Cr−25.8Mo, (a)
• wherein Ms represents a transformation starting temperature which is 250° C. or less, and wherein each of C, Si, Mn, Cu, Ni, Cr and Mo in formula (a) represents the composition in mass % in the welding metal, and
• wherein the welding metal has a microstructure which consists of martensite and the welding metal is in a state in which a compressive residual stress is imparted through the transformation of the welding metal during a welding into martensite.