Abstract: A double side welding method used for producing a differential gear for welding a weld part to join a ring gear fitted on a gear case from both sides. The method uses welding distortion caused by welding to improve product accuracy. The method includes welding from both sides of a weld part where a first member and a second member, which are the objects being joined, face each other. The method is performed by first welding, which is performed from one side, and second welding, which is performed from the other opposite side from that first welding. Heat quantity adjustment, that adjusts the quantity of heat input to the weld part for the second welding, is performed after the first welding, and is carried out such that an amount of welding distortion that is the objective arises.

Abstract: A welded structure has a first member and a second member that are welded together. The first member comprises a second-member joining part, and the second member comprises a first-member joining part. If the direction in which the first member and the second member are arranged is the first direction, and the direction intersecting the first direction is the second direction, welded parts are provided at least at both ends in the second direction of the joining surface where the first member and the second member are joined. The first member is such that the second-member joining part and a linking part which connects to the second-member joining part are arranged in succession from the joining surface in the first direction, and the dimensions of the second-member joining part are greater than the dimensions of the linking part in a third direction perpendicular to the first direction.

Abstract: An iron (Fe)-based austenitic heat-resistant cast steel includes, based on a total of 100 mass % (indicated below simply as “%”): 0.4 to 0.8% of carbon (C), 3.0% or less of silicon (Si), 0.5 to 2.0% of manganese (Mn), 0.05% or less of phosphorus (P), 0.03 to 0.2% of sulfur (S), 18 to 23% of chromium (Cr), 3.0 to 8.0% of nickel (Ni) and 0.05 to 0.4% of nitrogen (N). A ratio of chromium (Cr) to carbon (C) is in a range of 22.5?Cr/C?57.5. The cast steel includes one or two or more of vanadium (V), molybdenum (Mo), tungsten (W) and niobium (Nb) in a total amount of less than 0.2%.

Abstract: Assuming that a direction in which a first member and a second member are arranged is a first direction and a direction orthogonal to the first direction is a second direction, a welding structure includes: a pressure fit portion; a first cavity; a second cavity; a first weld bead formed between the first cavity and an end of a joining part of the first member and the second member on one side in the second direction by welding the first member and second member while the second cavity is communicated with outside; a second weld bead formed between the second cavity and an end of the joining part on the other side in the second direction; and a cutout groove communicating between the first cavity and the second cavity.

Abstract: A welded structure and welding method make it possible to improve welding strength and welding quality. A welded structure in which a first member and a second member are joined by welding, wherein the first member comprises a second-member joining part which is joined to the second member, and the second member comprises a first-member joining part which is joined to the first member. If the direction in which the first member and the second member are arranged is the first direction, and the direction intersecting the first direction is the second direction, the welded structure comprises a cavity part which is provided between the first-member joining part and the second-member joining part, and a welded part which is provided between the cavity part and both end parts in the second direction of the joining surface where the first-member joining part and the second-member joining part are joined.

Abstract: Assuming that a direction in which a first member and a second member are arranged is a first direction and a direction orthogonal to the first direction is a second direction, a welding structure includes: a pressure fit portion; a first cavity; a second cavity; a first weld bead formed between the first cavity and an end of a joining part of the first member and the second member on one side in the second direction by welding the first member and second member while the second cavity is communicated with outside; a second weld bead formed between the second cavity and an end of the joining part on the other side in the second direction; and a cutout groove communicating between the first cavity and the second cavity.

Abstract: When welding from both sides of a weld part where a first member and a second member, which are the objects being joined, face each other is performed by first welding performed from one side and second welding performed from the other opposite side from that first welding, heat quantity adjustment, that adjusts the quantity of heat input to the weld part for the second welding, which is performed after the first welding, is carried out such that an amount of welding distortion that is the objective arises.

Abstract: Ferritic spheroidal graphite cast iron includes: 3.1 to 3.5 percent by mass of carbon; 4.1 to 4.5 percent by mass of silicon; 0.8 percent by mass or below of manganese; 0.1 to 0.6 percent by mass of molybdenum; 0.1 to 1.0 percent by mass of chromium; 0.03 to 0.1 percent by mass of phosphorus; 0.03 percent by mass or below of sulfur; 0.02 to 0.15 percent by mass of magnesium; and iron.

Abstract: An iron (Fe)-based austenitic heat-resistant cast steel includes, based on a total of 100 mass % (indicated below simply as “%”): 0.4 to 0.8% of carbon (C), 3.0% or less of silicon (Si), 0.5 to 2.0% of manganese (Mn), 0.05% or less of phosphorus (P), 0.03 to 0.2% of sulfur (S), 18 to 23% of chromium (Cr), 3.0 to 8.0% of nickel (Ni) and 0.05 to 0.4% of nitrogen (N). A ratio of chromium (Cr) to carbon (C) is in a range of 22.5?Cr/C?57.5. The cast steel includes one or two or more of vanadium (V), molybdenum (Mo), tungsten (W) and niobium (Nb) in a total amount of less than 0.2%.

Abstract: Disclosed are a welded structure and a welding method which make it possible to improve welding strength and welding quality. A welded structure in which a first member and a second member are joined by means of welding, wherein the first member comprises a second-member joining part which is joined to the second member, and the second member comprises a first-member joining part which is joined to the first member. If the direction in which the first member and the second member are arranged is the first direction, and the direction intersecting the first direction is the second direction, welded parts are provided at least at both ends in the second direction of the joining surface where the first member and the second member are joined.

Abstract: Disclosed are a welded structure and a welding method which make it possible to improve welding strength and welding quality. A welded structure in which a first member and a second member are joined by means of welding, wherein the first member comprises a second-member joining part which is joined to the second member, and the second member comprises a first-member joining part which is joined to the first member. If the direction in which the first member and the second member are arranged is the first direction, and the direction intersecting the first direction is the second direction, the welded structure comprises a cavity part which is provided between the first-member joining part and the second-member joining part, and a welded part which is provided between the cavity part and both end parts in the second direction of the joining surface where the first-member joining part and the second-member joining part are joined.

Abstract: Ferritic spheroidal graphite cast iron includes: 3.1 to 3.5 percent by mass of carbon; 4.1 to 4.5 percent by mass of silicon; 0.8 percent by mass or below of manganese; 0.1 to 0.6 percent by mass of molybdenum; 0.1 to 1.0 percent by mass of chromium; 0.03 to 0.1 percent by mass of phosphorus; 0.03 percent by mass or below of sulfur; 0.02 to 0.15 percent by mass of magnesium; and iron.