Abstract: A gas shielded arc welding wire contains, based on total mass of the wire in terms of mass %: C: 0.01% to 0.50%; Si: 0.01% to 1.50%; Mn: 0.10% to 2.50%; Cr: 5% to 15%; Ni: 0.05% to 1.50%; Mo: 0.1% to 2.0%; V: 0.1% to 1.0%; Nb: 0.01% to 0.20%; REM: 0.001% to 0.050%; S: 0.0010% to 0.0200%; and O: 0.025% or less (including 0%), which satisfies the following relationship: 3.0?(Nb+10×REM)/(S+O)?200.0.

Abstract: A gas shielded arc welding method includes welding a steel sheet with a tensile strength of 780 MPa or more using a shielding gas containing Ar in an amount of 92 vol. % to 99.5 vol. %. In the gas shielded arc welding method, a value calculated from the following expression (1) is 0.20 or more: {?v/(D/2)2}×10?{(100?CAr)×I/v}×0.1 . . . (1), where CAr represents an Ar content (vol. %) in the shielding gas, D represents an inner diameter (mm) of a nozzle from which the shielding gas is supplied, v represents a welding speed (cm/min), and I represents a welding current (A).

Abstract: An arc welding solid wire includes: a steel material; and a copper plating layer formed on a surface of the steel material, in which an amount of Cu in the steel material and the copper plating layer is 0.05 mass % to 0.30 mass % with respect to a total mass of the wire, a surface of the wire is coated with 0.05 g to 0.20 g of oil with respect to 1 kg of the wire, and on a surface of the copper plating layer, an arithmetic average roughness Rac in a circumferential direction is 0.25 µm to 1.00 µm, and an arithmetic average roughness Ral in a longitudinal direction is 0.07 µm to 0.50 µm.

Abstract: A wire for gas-shielded arc welding includes, based on a total mass of the wire: C: 0.01 mass % or more and 0.10 mass % or less, Si: 0.05 mass % or more and 0.55 mass % or less, Mn: 1.60 mass % or more and 2.40 mass % or less, Ti: 0.05 mass % or more and 0.25 mass % or less, Cu: 0.01 mass % or more and 0.30 mass % or less, S: 0.001 mass % or more and 0.020 mass % or less, N: 0.0045 mass % or more and 0.0150 mass % or less, Al: 0.10 mass % or less, and P: 0.025 mass % or less, with the remainder being Fe and inevitable impurities. In the wire, the following relationship is satisfied: 0.1?[Ti]/[Si]?3.0, where [Si] is the content of Si (mass %) and [Ti] is the content of Ti (mass %).

Abstract: A wire for gas-shielded arc welding includes, based on a total mass of the wire: C: 0.01 mass % or more and 0.10 mass % or less, Si: 0.05 mass % or more and 0.55 mass % or less, Mn: 1.60 mass % or more and 2.40 mass % or less, Ti: 0.05 mass % or more and 0.25 mass % or less, Cu: 0.01 mass % or more and 0.30 mass % or less, S: 0.001 mass % or more and 0.020 mass % or less, N: 0.0045 mass % or more and 0.0150 mass % or less, Al: 0.10 mass % or less, and P: 0.025 mass % or less, with the remainder being Fe and inevitable impurities. In the wire, the following relationship is satisfied: 0.1?[Ti]/[Si]?3.0, where [Si] is the content of Si (mass %) and [Ti] is the content of Ti (mass %).

Abstract: A gas shielded arc welding wire contains, based on total mass of the wire in terms of mass %: C: 0.01% to 0.50%; Si: 0.01% to 1.50%; Mn: 0.10% to 2.50%; Cr: 5% to 15%; Ni: 0.05% to 1.50%; Mo: 0.1% to 2.0%; V: 0.1% to 1.0%; Nb: 0.01% to 0.20%; REM: 0.001% to 0.050%; S: 0.0010% to 0.0200%; and O: 0.025% or less (including 0%), which satisfies the following relationship: 3.0?(Nb+10×REM)/(S+O)?200.0.

Abstract: A gas shielded arc welding method includes welding a steel sheet with a tensile strength of 780 MPa or more using a shielding gas containing Ar in an amount of 92 vol. % to 99.5 vol. %. In the gas shielded arc welding method, a value calculated from the following expression (1) is 0.20 or more: {?v/(D/2)2}×10?{(100?CAr)×I/v}×0.1 . . . (1), where CAr represents an Ar content (vol. %) in the shielding gas, D represents an inner diameter (mm) of a nozzle from which the shielding gas is supplied, v represents a welding speed (cm/min), and I represents a welding current (A).

Abstract: A compression coil spring having high durability can be provided by using an inexpensive wire material. The present invention provides a compression coil spring formed by using a steel wire material, the steel wire material made of C: 0.45 to 0.85 mass %, Si: 0.15 to 2.5 mass %, Mn: 0.3 to 1.0 mass %, Fe and inevitable impurities as a remainder, and a circle-equivalent diameter of 1.5 to 9.0 mm, wherein hardness of a freely selected cross-section of the wire material is 570 to 700 HV, and at an inner diameter side of the coil spring, unloaded compressive residual stress at a depth of 0.2 mm from a surface in an approximate maximal main stress direction in a case in which compressive load is loaded on the spring is 200 MPa or more, and unloaded compressive residual stress at a depth of 0.4 mm from surface is 100 MPa or more.

Abstract: The present invention provides a weld metal that exhibits excellent strength and toughness as well as excellent SR cracking resistance that can prevent SR cracking not only at a high temperature of about 690° C. but also at around 600° C., at which temperature SR cracking tends to occur. The weld metal of the present invention includes, C: 0.06 to 0.10%, Si: 0.4 to 0.6%, Mn: 0.5 to 1.0%, Cr: 1.8 to 3.0%, Mo: 0.8 to 1.2%, Ti: 0.02 to 0.08%, B: 0.002% or less (including 0%), N: 0.005 to 0.01%, and O: 0.03 to 0.07%, with the balance being iron and inevitable impurities, wherein the weld metal satisfies the following inequality expression (1): 3.0?13×[C]+[Cr]+160×[B]?4.0??(1) where [C] is a C content, [Cr] is a Cr content, and [B] is a B content.

Abstract: A titanium alloy has high strength and superior workability and is preferably used for various structural materials for automobiles, etc. The titanium alloy is obtained by the following production method. An alloy having a structure of ?? martensite phase is hot worked at conditions at which dynamic recrystallization occurs. The working is performed at a heating rate of 50 to 800° C./second at a strain rate of 0.01 to 10/second when the temperature is 700 to 800° C. or at a strain rate of 0.1 to 10/second when the temperature is more than 800° C. and less than 1000° C. so as to provide a strain of not less than 0.5. Thus, equiaxed crystals with an average grain size of less than 1000 nm are obtained.

Abstract: A compression coil spring having high durability can be provided by using an inexpensive wire material. The present invention provides a compression coil spring formed by using a steel wire material, the steel wire material made of C: 0.45 to 0.85 mass %, Si: 0.15 to 2.5 mass %, Mn: 0.3 to 1.0 mass %, Fe and inevitable impurities as a remainder, and a circle-equivalent diameter of 1.5 to 9.0 mm, wherein hardness of a freely selected cross-section of the wire material is 570 to 700 HV, and at an inner diameter side of the coil spring, unloaded compressive residual stress at a depth of 0.2 mm from a surface in an approximate maximal main stress direction in a case in which compressive load is loaded on the spring is 200 MPa or more, and unloaded compressive residual stress at a depth of 0.4 mm from surface is 100 MPa or more.

Abstract: A titanium alloy has high strength and superior workability and is preferably used for various structural materials for automobiles, etc. The titanium alloy is obtained by the following production method. An alloy having a structure of ?? martensite phase is hot worked at conditions at which dynamic recrystallization occurs. The working is performed at a heating rate of 50 to 800° C./second at a strain rate of 0.01 to 10/second when the temperature is 700 to 800° C. or at a strain rate of 0.1 to 10/second when the temperature is more than 800° C. and less than 1000° C. so as to provide a strain of not less than 0.5. Thus, equiaxed crystals with an average grain size of less than 1000 nm are obtained.

Abstract: The invention provides a steel product excellent in corrosion resistance and corrosion fatigue resistance, comprising a, coating film on the surface of the steel product, wherein a ratio of the number of Al atoms to the total number of Fe, C, Al, P and O atoms and optionally added Si, Mn and Cr atoms is 0.5% or more in an average composition of the coating film, and the number of Al atoms in the average composition of the coating film is higher than the number of Al atoms in an average composition of the steel pro duct before surface treatment.