Disclosed are a wire rod for a steel fiber having a strength of 1,500 MPa or more without performing LP heat treatment during a wire drawing process, a steel fiber and, a method for manufacturing the same. The wire rod for a high-strength steel fiber according to the present disclosure includes, in percent by weight (wt %), 0.01 to 0.03% of C, 0.05 to 0.15% of Si, 1.0 to 2.0% of Mn, 0.05 to 0.15% of P, 0.005% or less (excluding 0) of Al, 0.01% or less (excluding 0) of N, 0.03% or less (excluding 0) of S, 0.02 to 0.08% of Sn, and the remainder of Fe and inevitable impurities, wherein a microstructure is single-phase ferrite.

The present invention discloses a wire rod for an ultrahigh-strength steel cord and a manufacturing method thereof. The manufacturing method includes: smelting molten steel where inclusions in sizes ≥5 μm are at a number density ≤0.5/mm.sup.2 and sizes of inclusions are ≤30 μm; casting the molten steel into an ingot blank with a center carbon segregation value of 0.92-1.08; cogging the ingot blank into an intermediate blank with a center carbon segregation value of 0.95-1.05; rolling the intermediate blank into a wire rod; and performing temperature control cooling on the wire rod to obtain a wire rod with high purity, high homogeneity and tensile strength ≤1,150 MPa. The wire rod may be used for an ultrahigh-strength steel cord with single tensile strength ≥3,600 MPa.

A bar-shaped stainless steel product contains, by mass %, 0.001 to 0.030% of C, 0.01 to 4.00% of Si, 0.01 to 2.00% of Mn, 0.01 to 4.00% of Ni, 6.0 to 35.0% of Cr, 0.01 to 5.00% of Mo, 0.01 to 2.00% of Cu, and 0.001 to 0.050% of N. In the product, an F value is 20 or less, a rolling-direction-crystal-orientation RD//<100> fraction is 0.05 or more, and preferably a rolling-direction-crystal-orientation RD//<334> fraction is 0.2 or less. The above RD//<100> fraction means an area ratio of crystal having 25 degrees or less of an orientation difference between a <100> orientation and a rolling direction, and the above RD//<334> fraction means an area ratio of crystal having 10 degrees or less of an orientation difference between a <334> orientation and a rolling direction. F value=700C+800N+20Ni+10Cu+10Mn−6.2Cr−9.2Si−9.3Mo−74.4Ti−37.2A1−3.1Nb+63.2

Herein is provided a ferrous shape memory alloy (SMA) wire and processes for production of ferrous shape memory alloy wire that do not require crystallographic texturing processes to achieve superior superelastic and SMA wire properties. The shape memory alloy wire includes an elongated wire body with a longitudinal-axis length of iron alloy material and has a cross-sectional wire diameter that is less than about 1 millimeter. The iron alloy material has an oligocrystalline crystallographic morphology along the longitudinal-axis length. The iron alloy material has a ′-fcc crystallographic matrix and a volume fraction of ′-LH crystallographic precipitates in the ′-fee crystallographic matrix.

An aspect of the present invention is to provide high-strength ultra-thick steel with excellent cryogenic strain aging impact toughness at the center thereof, and a method for manufacturing same. An embodiment of the present invention provides high-strength ultra-thick steel with excellent cryogenic strain aging impact toughness at the center thereof, and a method for manufacturing same, the steel comprising, by wt %, 0.02-0.06% of C, 1.8-2.2% of Mn, 0.7-1.1% of Ni, 0.2-0.5% of Mo, 0.005-0.03% of Nb, 0.005-0.018% of Ti, 80 ppm or less of P, 20 ppm or less of S, and the remainder of Fe and other evitable impurities, wherein the average grain size of grains having a high boundary angle of 15 degrees or greater is 15 μm or less as measured in a range of ⅜t-⅝t in the thickness (t) direction by EBSD.

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: 0.30 mass % or less, Al: 0.10 mass % or less, P: 0.025 mass % or less, and S: 0.010 mass % or less with the remainder being Fe and inevitable impurities. In addition, the following relationship is satisfied: 0.1≤[Ti]/[Si]≤3.0, where [Si] is the content of Si (mass %) based on the total mass of the wire and [Ti] is the content of Ti (mass %) based on the total mass of the wire.

The present invention relates to a manufacturing method of 800 MPa grade steel bar and the 800 MPa grade steel bar produced therefrom. The 800 MPa grade steel bar produced by the manufacturing method comprises, in weight percentages, the following composition: carbon, 0.10%-0.30%; manganese, 7.00%-11.00%; aluminum, 1.00%-3.00%; silicon, 0-1.00%; vanadium, 0.05%-0.30%; niobium; 0-0.10%; and the balance of Fe and inevitable impurities; the manufacturing method comprises the steps of smelting to obtain molten steel containing components of the steel bar; forming the molten steel into a billet by casting; heating the billet to a temperature T1 of 1050° C.≤T1≤1200° C. and thermally insulating for 1.5-2.5 hours; performing hot rolling on the thermally insulated billet, the finishing rolling temperature T2 being 500° C.≤T2≤800° C.; and naturally cooling the hot-rolled billet to ambient temperature. The hot-rolled steel bar of the present invention has a dual-phase microstructure of martensite and austenite. The hot rolled steel bar both has a high yield strength of 800-1000 MPa, an ultra-high tensile strength of 1300 MPa-1900 MPa, an ultra-high tensile to yield ratio of 1.6-2.2, and a high uniform elongation of 8%-20%.

A bioabsorbable wire material includes manganese (Mn) and iron (Fe). One or more additional constituent materials (X) are added to control corrosion in an in vivo environment and, in particular, to prevent and/or substantially reduce the potential for pitting corrosion. For example, the (X) element in the Fe—Mn—X system may include nitrogen (N), molybdenum (Mo) or chromium (Cr), or a combination of these. This promotes controlled degradation of the wire material, such that a high percentage loss of material the overall material mass and volume may occur without fracture of the wire material into multiple wire fragments. In some embodiments, the wire material may have retained cold work for enhanced strength, such as for medical applications. In some applications, the wire material may be a fine wire suitable for use in resorbable in vivo structures such as stents.

An elongated steel element having a non-round cross-section and being in a work-hardened state, said elongated steel element having as steel composition: a carbon content ranging from 0.20 weight percent to 1.00 weight percent, a silicon content ranging from 0.05 weight percent to 2.0 weight percent, a manganese content ranging from 0.40 weight percent to 1.0 weight percent, a chromium content ranging from 0.0 weight percent to 1.0 weight percent, a sulfur and phosphor content being individually limited to 0.025 weight percent, contents of nickel, vanadium, aluminium, molybdenum or cobalt all being individually limited to 0.5 weight percent, the remainder being iron and unavoidable impurities, said steel having martensitic structure that comprises martensitic grains, wherein a fraction of at least 10 volume percent of martensitic grains is oriented.

A high-strength spring steel coil spring of a vehicle suspension, having excellent corrosion resistance, may include 0.4 to 0.9 wt % of C, 0.9 to 2.3 wt % of Si, 0.5 to 1.2 wt % of Mn, 0.6 to 1.5 wt % of Cr, 0.01 to 0.5 wt % of Mo, 0.01 to 0.9 wt % of Ni, 0.5 wt % or less (excluding 0 wt %) of V, 0.5 wt % or less (excluding 0 wt %) of Nb, 0.3 wt % or less (excluding 0 wt %) of Ti, 1.0 wt % or less (excluding 0 wt %) of Co, 0.1 wt % or less (excluding 0 wt %) of B, 0.3 wt % or less (excluding 0 wt %) of W, 0.3 wt % or less (excluding 0 wt %) of Cu, 0.3 wt % or less (excluding 0 wt %) of Al, 0.03 wt % or less (excluding 0 wt %) of N, 0.003 wt % or less (excluding 0 wt %) of O, and a remainder of Fe and inevitable impurities.