Abstract: Provided are a welding method and a weld joint with which the fatigue strength of the box-welded joint of a gusset plate and a high-tensile steel can be dramatically improved. A welding method whereby a gusset plate is welded to high-tensile steel by means of box-welding, with a bead having a length of 17 mm or greater being formed at the ends of the gusset plate in the lengthwise direction using a welding material for which the martensite transformation starting temperature of the weld metal is 350° C. or less. In addition, a weld joint formed by welding a gusset plate to high-tensile steel using the aforementioned method; a method for repairing or reinforcing a box-welded part.

Abstract: In the present invention, an iron based alloy which contains by mass %: 0.20% or less of C; 6.0 to 16.0% of Cr; 6.0 to 16.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 0-170° C., inclusive of 0° C. and exclusive of 170° C., is used as a welding material. With respect to a weld metal, the weld metal has a iron alloy composition which contains by mass %: 0.20% or less of C; 3.0 to 13.0% of Cr; 3.0 to 13.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 50-360° C., inclusive of both 50° C. and 360° C.

Abstract: In the present invention, an iron based alloy which contains by mass %: 0.20% or less of C; 6.0 to 16.0% of Cr; 6.0 to 16.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 0-170° C., inclusive of 0°C and exclusive of 170° C., is used as a welding material. With respect to a weld metal, the weld metal has a iron alloy composition which contains by mass %: 0.20% or less of C; 3.0 to 13.0% of Cr; 3.0 to 13.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 50-360° C., inclusive of both 50° C. and 360° C.

Abstract: A gas having an arc current-voltage property that is different from a shielding gas is intermittently added to the shielding gas, an arc current is intermittently changed in proportion to an intermittent chemical composition change of the shielding gas at an arc generation region, and an arc generation point situated at a tip of a welding wire is displaced upwardly or downwardly along a groove of a base metal.

Abstract: In the present invention, an iron based alloy which contains by mass %: 0.20% or less of C; 6.0 to 16.0% of Cr; 6.0 to 16.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 0-170° C., inclusive of 0° C. and exclusive of 170° C., is used as a welding material. With respect to a weld metal, the weld metal has a iron alloy composition which contains by mass %: 0.20% or less of C; 3.0 to 13.0% of Cr; 3.0 to 13.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 50-360° C., inclusive of both 50° C. and 360° C.

Abstract: In the present invention, an iron based alloy which contains by mass %: 0.20% or less of C; 6.0 to 16.0% of Cr; 6.0 to 16.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 0-170° C., inclusive of 0° C. and exclusive of 170° C., is used as a welding material. With respect to a weld metal, the weld metal has a iron alloy composition which contains by mass %: 0.20% or less of C; 3.0 to 13.0% of Cr; 3.0 to 13.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 50-360° C., inclusive of both 50° C. and 360° C.

Abstract: On a method of welding a high nitrogen containing stainless steel using, as a base metal, a high nitrogen stainless steel containing nitrogen at or above a solubility equilibrated with N2 at 1 atm when melted, a novel welding method keeping a weld metal composition from supersaturation of N in a molten state, having a sufficient corrosion resistance in an average composition of the weld metal under sea water circumstance and capable of maintaining mechanical characteristics and corrosion resistance comparable with those of a base metal is provided, wherein welding is conducted while setting a composition of a welding material and a dilution rate to be defined latter so as to satisfy the following two relations (A) and (B): 1 % ⁢ N p × D ≦ 0.028 × ( % ⁢   ⁢ Cr p × D + % ⁢   ⁢ Cr ′ × ( 1 - D ) ) + 0.

Abstract: A different kind of a gas in an arc current-voltage property from an shielding gas is intermittently added to the shielding gas, an arc current is intermittently changed in proportion to an intermittent chemical composition change of the shielding gas at an arc generation region, and an arc generation point situated at a tip of a welding wire is displaced upward or downward along a groove of a base metal.

Abstract: A welding method for two members adapted to be welded and formed of a low-alloy steel for structural purposes causing the weld metal to develop martensite transformation during cooling after welding, so that the weld metal becomes expanded to a greater degree at room temperature than at a temperature at which the martensite transformation initiates. The welding material comprises a ferrous alloy containing C, Cr, Ni, Si, Mn, Mo and Nb, all of which meet substantially with the contents of the following equation (1): 170≦719−(795×C wt %)−(23.7×Cr wt %)−(26.5×Ni wt %)−(35.55×Si wt %)−(13.25×Mn wt %)−(23.7×Mo wt %)−(11.85×Nb wt %)<250  (1).

Abstract: A welding method for two members adapted to be welded and formed of a low-alloy steel for structural purposes causing the weld metal to develop martensite transformation during cooling after welding, so that the weld metal becomes expanded to a greater degree at room temperature than at a temperature at which the martensite transformation initiates.

Abstract: There is provided a low-temperature service nickel steel plate with excellent weld toughness. This steel plate consists essentially of not less than 0.03% of C, 0.02 to 0.22% of Si, 0.05 to 0.47% of Mn, not more than 0.005% of P, not more than 0.005% of S, 7.5 to 12.0% of Ni, 0.01 to 0.10% of Al, and the remaining of Fe, where the following relations stand 3.5%.ltoreq.(8Si+9Mn).ltoreq.5.1% and 123C+(8Si+9Mn).ltoreq.10.9%.