An oil ring wire (2) containing an alloy steel as a material. The alloy steel contains: 0.50 to 0.65% by mass C; 1.60 to 2.30% by mass Si; 0.60 to 1.10% by mass Mn; 0.75 to 1.15% by mass Cr; 0.18 to 0.45% by mass Ni; 0.05 to 0.15% by mass V; and 0.15% by mass or less Cu. In the oil ring wire 2, an area percentage of a carbide is 1.00% or less. Also disclosed is a method of producing the oil ring wire.

This invention generally relates to the field of nonferrous metallurgy, namely to titanium alloy materials with specified mechanical properties for manufacturing the aircraft fasteners. A stock for high strength fastener is manufactured from wrought titanium alloy containing, in weight percentages, 5.5 to 6.5 Al, 3.0 to 4.5 V, 1.0 to 2.0 Mo, 0.3 to 1.5 Fe, 0.3 to 1.5 Cr, 0.05 to 0.5 Zr, 0.15 to 0.3 O, 0.05 max. N, 0.08 max. C, 0.25 max. Si, balance titanium and inevitable impurities, having the value of aluminum structural equivalent [Al] eq in the range of 7.5 to 9.5, and the value of molybdenum structural equivalent [Mo] eq in the range of 6.0 to 8.5, where the equivalents are defined by the following equations: [Al] eq=[Al]+[O]10+[Zr]/6; [Mo] eq=[Mo]+[V]/1.5+[Cr]1.25+[Fe]2.5. A manufacturing method for a stock for high strength fastener includes melting of titanium alloy ingot, production of forged billed from ingot at beta and/or alpha-beta phase field temperatures, hot rolling at a heating temperature of beta and/or alpha-beta phase field to produce a round stock, subsequent annealing of a rolled stock at a temperature of 550 C. to 705 C. (1022 F. to 1300 F.) for at least 0.5 hour followed by drawing to produce a wire with diameter up to 10 mm (0.394 inches) and subsequent annealing at a temperature of 550 C. to 705 C. (1022 F. to 1300 F.) for at least 0.5 hour. A technical result is production of a titanium alloy stock for high strength fastener having high ultimate tensile strength and double shear strength while maintaining a high level of plastic properties in the annealed condition.

Disclosed are wire rods and parts with improved delayed fracture resistance, and methods for manufacturing the same. The wire rod with improved delayed fracture resistance according to the present disclosure contains, by wt %, 0.15-0.30% of C, 0.15-0.25% of Si, 0.95-1.35% of Mn, 0.030% or less of P, 0.030% or less of S, 0.015-0.030% of Ti, 0.0010-0.0040% of B, 0.0010-0.0080% of N, and Fe and inevitable impurities as the balance, and satisfies formula 1 of 2.05.5[Si]+[Mn]2.4, where [Si] and [Mn] represent the contents (wt %) of the corresponding elements.

The present disclosure relates to a CHQ wire rod that has improved resistance to hydrogen delayed fracture while securing cold forging characteristics by reducing Si content and adding Mo and V, a processed product using the same, and a manufacturing method thereof. In accordance with an aspect of the present disclosure, a CHQ wire rod includes, in percent (%) by weight of the entire composition, C: 0.3 to 0.5%, Si: 0.1 to 0.3%, Mn: 0.5 to 1.0%, at least two or more of Cr: 0.5 to 1.5%, Mo: 0.5 to 1.5%, V: 0.01 to 0.2%, the remainder of iron (Fe) and other inevitable impurities, and the value of the following formula (1) is 3.56 or more.

Disclosed in the present specification are: a high-strength wire rod for cold heading, having superior heat treatment characteristics and resistance of hydrogen-delayed fracture characteristics, the rod being applicable to a bolt, etc.; a heat-treated component; and a method for manufacturing the same. According to an exemplary embodiment, the high-strength wire rod for cold heading with superior heat treatment characteristics and resistance of hydrogen-delayed fracture characteristics comprises, by wt %, 0.3-0.6% of C, 0.05-0.3% of Si, 0.2-1.0% of Mn, 0.5-2.0% of Cr, 0.5-2.0% of Mo, 0.02-0.05% of Al, 0.01-0.03% of N, and Fe and other impurities as the balance, and has a microstructure comprising, by area fraction, 80% or more of bainite, 1-15% of pearlite and 0.1-2% of martensite, and comprises 210.sup.19/m.sup.3 or more of aluminum nitride having a diameter of 5-50 nm.

Disclosed in the present specification are: a wire rod for ultrahigh-strength springs, which can be applied to motorcycle suspension springs; a steel wire; and a manufacturing method therefor. According to one embodiment of the disclosed wire rod for ultrahigh-strength springs, the wire rod comprises, by wt %, 0.5-0.7% of C, 0.4-0.9% of Si, 0.3-0.8% of Mn, 0.2-0.6% of Cr, 0.015% or less of P, 0.010% or less of S, 0.01% or less of Al, 0.01% or less of N, 0.005% or less of O, and the balance of Fe and inevitable impurities, wherein in 1 mm2 area of the center of the cross-section perpendicular to the longitudinal direction, the proportion of the area satisfying at least one from among C>0.8%, Si>0.9%, Cr>0.8% and Mn>0.8% by wt % can be 5% or less.

Disclosed are a wire rod and a steel wire for a spring, a spring with improved fatigue resistance and nitriding property, and methods for manufacturing same. The wire rod for a spring with improved fatigue resistance and nitriding property according to the present disclosure contains, by wt %, 0.6-0.7% of C, 2.0-2.5% of Si, 0.2-0.5% of Mn, 0.9-1.6% of Cr, 0.015% of less of P, 0.01% of less of S, 0.01% of less of Al, 0.007% of less of N, 0.1-0.25% of Mo, 0.1-0.25% of V, and Fe and inevitable impurities as the balance, wherein Cr+Mn is 1.8% or less, Mo/V is 1.5 or less, and the microstructure includes 60% or more of a pearlite structure in the C section.

Disclosed are high-strength wire rods and parts, having improved delayed fracture resistance, for use in bolts, and a methods for manufacturing the same. The high-strength wire rod, having improved delayed fracture resistance, for use in bolts according to the present disclosure contains, by wt %, 0.15-0.30% of C, 0.05-0.35% of Si, 0.95-1.35% of Mn, 0.030% or less of P, 0.030% or less of S, 0.005-0.030% of Ti, 0.0010-0.0040% of B, and Fe and inevitable impurities as the balance.

Provided is a wire rod for a concrete reinforcing steel fiber, a steel fiber, and a manufacturing method therefor. According to one disclosed embodiment of a wire rod for a concrete reinforcing steel fiber, the wire rod comprises, by weight, C: 0.01 to 0.04%, Si: 0.07 to 0.3%, Mn: 1.0 to 2.0%, P: 0.1 to 0.3% and the balance of Fe and other unavoidable impurities, wherein, when the radius of the wire rod is r, in a region from the center of a cross section perpendicular of the longitudinal direction to 0.95*r, the area fraction of ferrite is 90% or more, and the remainder comprises pearlite, wherein the average grain size of the ferrite may be 30 m or less and the colony size of the pearlite may be 10 m or less.

A spring steel wire includes a main body made of a steel and having a line shape, and an oxidized layer covering an outer peripheral surface of the main body. The steel constituting the main body contains not less than 0.5 mass % and not more than 0.7 mass % C, not less than 1 mass % and not more than 2.5 mass % Si, not less than 0.2 mass % and not more than 1 mass % Mn, and not less than 0.5 mass % and not more than 2 mass % Cr, with the balance being Fe and unavoidable impurities. The steel constituting the main body has a pearlite structure. The oxidized layer has a thickness of not less than 2 m and not more than 5 m. The oxidized layer contains not less than 60 mass % Fe.sub.3O.sub.4.