A method for manufacturing a strand from a stainless steel by cold forming a billet into the cold-hardened strand and subsequently annealing the strand is provided. The method allows stainless steel strands to be produced, which have both a high tensile strength, as well as a high degree of elongation. The strand is heated to a temperature ranging from 400 C. to 460 C. while the strand is being annealed, and the cold-hardened strand is surrounded by a protective gas atmosphere during the heating process.

A steel composition is provided and includes carbon of about 0.5 to 0.7 wt %; silicon of about 1.3 to 2.3 wt %; manganese of about 0.6 to 1.2%; chromium of about 0.6 to 1.2 wt %; molybdenum of about 0.1 to 0.5 wt %; nickel of about 0.05 to 0.8 wt %; vanadium of about 0.05 to 0.5 wt %; niobium of about 0.05 to 0.5 wt %; titanium of about 0.05 to 0.3 wt %; cobalt of about 0.01 to 3 wt %; zirconium of about 0.001 to 0.2 wt %; yttrium of about 0.01 to 1.5 wt %; copper of about 0.3% or less but greater than 0 wt %; aluminum of about 0.3% or less but greater than 0 wt %; nitrogen of about 0.03% or less but greater than 0 wt %; oxygen of about 0.003% or less but greater than 0 wt %. Additionally, a balance iron, based on the total weight is included.

A case hardening steel suitable as raw material for producing a mechanical structural part having high rotating bending fatigue strength and pitting fatigue strength at relatively low cost and a method of producing the case hardening steel are provided. A case hardening steel comprises a chemical composition containing, in mass %, C, Si, Mn, P, S, Cr, Mo, Al, N, and O in a predetermined relationship, with a balance being Fe and inevitable impurities, wherein I80 (where I denotes an area (m.sup.2) of an oxide-based inclusion located in a fish eye central portion at a fracture surface after subjecting the case hardening steel to carburizing-quenching and tempering and then performing a rotating bending fatigue test).

A resistance annealing furnace for annealing a metal wire, strand, string, wire rod or strap having at least two electric axes provided with respective pulleys to convey the metal wire and a DC voltage generator suppliable with an AC voltage to generate an annealing voltage applied between the two electric axes so as to provoke the annealing due to Joule effect. The DC voltage generator has active supplying means supplied with the AC voltage so as to generate an intermediate DC voltage, a pulse width modulator to transform the intermediate voltage into a first PWM voltage with the same amplitude, a voltage transformer to transform the first PWM voltage into a second PWM voltage with a smaller amplitude, and a voltage rectifier stage to transform the second PWM voltage into the annealing voltage.

Disclosed are a metal wire, a manufacturing method therefor, and a tire. The metal wire is made by twisting a filament; an outer peripheral surface of the filament is covered with a CuMZn alloy coating; the outer peripheral surface of the filament is also covered with a CuZn alloy coating; the metal wire is made of at least one filament; an area covered by the CuMZn alloy coating is 10%-90% of an area of the outer peripheral surface of the filament, and the rest is the CuZn alloy coating; M in the CuMZn alloy coating is selected from one or two of Co, Ni, Mn, or Mo; the mass fraction of Cu in the CuMZn alloy coating is 58%-72%, the mass fraction of M in the CuMZn alloy coating is 0.5%-5%, and the balance in the CuMZn alloy coating is Zn and inevitable impurities.

A steel wire with improved drawability, and a manufacturing method therefor are disclosed. A steel wire according to the present invention comprises, by wt %, 0.52-0.69% of C, 0.3-0.8% of Mn, 0.1-0.5% of Si, and the balance of Fe and inevitable impurities, wherein the carbon content of cementite in pearlite is 7 at. % or more, and the following formula (1) is satsified.

[TS]+exp(?)*10<1500(1)

In Expression (1), [TS] means the tensile strength (MPa) of a wire before drawing, and e means draw strain.

A steel wire which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present embodiment consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, N: 0.0070% or less, Ca: 0 to 0.0050%, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/?m.sup.2.

A steel wire for a non heat-treated mechanical part includes, as a chemical composition, by mass %, a predetermined amount of C, Si, Mn, Cr, Mo, Ti, Al, B, Nb, and V, and limited P, S, N, and O and a remainder of Fe and impurities; in which a structure includes, by volume %, a bainite of greater than or equal to 75[C %]+25, and a remainder of one or more of a ferrite and a pearlite when an amount of C is set to [C %] by mass %; when an average aspect ratio of a bainite block in a second surface layer area of the steel wire is set as R1, the R1 is greater than or equal to 1.2; when an average grain size of a bainite block in a third surface layer area of the steel wire is set to P.sub.S3 m, and an average grain size of a bainite block in a third center portion of the steel wire is set to P.sub.C3 m, the P.sub.S3 satisfies Expression (c), and the P.sub.S3 and the P.sub.C3 satisfy Expression (d), a standard deviation of a grain size of the bainite block in the structure is less than or equal to 8.0 m; and a tensile strength is in a range of 800 MPa to 1600 MPa,
P.sub.S320/R1(c),
P.sub.S3/P.sub.C30.95(d).

A steel wire includes, as a chemical composition, by mass %, C: 0.40% to 1.10%, Si: 0.005% to 0.350%, Mn: 0.05% to 0.90%, Cr: 0% to 0.70%, Al: 0% to 0.070%, Ti: 0% to 0.050%, V: 0% to 0.10%, Nb: 0% to 0.050%, Mo: 0% to 0.20%, B: 0% to 0.0030%, and a remainder including Fe and impurities; in which a metallographic structure in a cross section includes 80 area % or more of a pearlite structure having a lamellar cementite; an average lamellar spacing which is a spacing between lamellar cementites is 28 nm to 80 nm; an average length of the lamellar cementite is 22.0 m or less; among the pearlite structure, a pearlite structure having the lamellar cementite of which an inclination with respect to a longitudinal direction of the steel wire is 15 or less is 40 area % or more; an integration degree of a {110} plane of a ferrite with respect to the longitudinal direction is in a range of 2.0 to 8.0, and a diameter of the steel wire is 1.4 mm or more.

The present invention relates to a high-hardenability, medium-carbon, low-alloy round steel for fasteners, the chemical constituents by mass percentage are as follows: C: 0.360.44%, Si: 0.150.40%, Mn: 0.801.00%, Cr: 1.001.15%, Mo: 0.050.25%, Ni: 0.050.25%, Cu: 0.050.25%, Al: 0.0150.050%, B: 0.00100.0050%, Ti: 0.0200.050%, the balance is Fe; the maximum diameter of the round steel is 65 mm. The manufacturing process are as follows: the raw materials are processed, in sequence, by converter smelting, LF refining, RH/VD degassing to obtain molten steel, feeding Ti wires and ferroboron, continuous casting, rolling into the bar, obtaining the quenched and tempered round steel after quenching and tempering treatment; the quenched and tempered round steel is able to be directly used in processing fasteners which meet ISO 898-1 standard for grade 10.9, such as bolts and the like.