Method of producing a cold drawn wire from a particle metallurgy steel includes the following steps:-preparation of a bulk of molten metal including in weight %: C 0.03-0.15, Si 0.01-1.2, Mn 0.1-1.5, Cr 15-20, Ni 540, Al 0.5-1.5, optionally max 2 of elements chosen from the group of N, P, S, Cu, Co, W, Mo, Nb, Ti, Zr, Ta, B, Be, Bi, Se, Mg, Ca, Hf, V, and REM, and, using electro slag refining and atomising to provide a metal powder; filling and sealing a capsule with the metal powder; compacting the capsule to provide a full density billet; hot working the billet and finishing by wire rolling; cold drawing the annealed wire with at least 30% area reduction.

The invention relates to a method for producing a sheet steel component by means of a press hardening or form hardening process, the sheet steel component being produced by virtue of the fact that a sheet bar composed of a dual-phase steel is cold-formed, then heated, and then quenched in a cooling press or a sheet bar composed of a dual-phase steel is heated to a temperature above the austenitization temperature of the highly hardenable steel material and is then formed into the sheet steel component in a single stroke or in a plurality of strokes in a forming and cooling press, wherein a dual-phase steel is used, whose Ac3 value is increased until at the required annealing temperatures, only a partial austenitization of the dual-phase steel takes place so that when loaded into the cooling press, the dual-phase steel has a ferritic matrix, and in addition to this, austenite is present.

The present disclosure relates to a duplex stainless steel comprising in weight % (wt %): C less than 0.03; Si less than 0.60; Mn 0.40 to 2.00; P less than 0.04; S less than or equal to 0.01; Cr more than 30.00 to 33.00; Ni 6.00 to 10.00; Mo 1.30 to 2.90; N 0.15 to 0.28; Cu 0.60 to 2.20; Al less than 0.05; balance Fe and unavoidable impurities. The present disclosure also relates to a component or a construction material comprising the duplex stainless steel. Additionally, the present disclosure also relates to a process for manufacturing a component comprising said duplex stainless steel.

Steel according to one embodiment of the present invention has predetermined chemical components, wherein in a region where a distance r from the center of a cross-section perpendicular to the length direction satisfies 0.7Rr0.9R, structures include ferrite and bainite, the average fraction of the ferrite is in the range of 40 to 70% in terms of area ratio, the total average fraction of the structures other than the ferrite and the bainite is 0% or more and 3% or less on average, and the balance includes bainite; and the standard deviation of a ferrite fraction in the region is 4% or less.

A method for producing a steel part and corresponding steel part includes casting a steel having a composition comprising: 0.10%C0.35%, 0.8%Si2.0%, 1.8%Mn2.5%, P0.1%, 0%S0.4%, 0%Al1.0%, N0.015%, 0%Mo0.4%, 0.02%Nb0.08%, 0.02%Ti0.05%, 0.001%B0.005%, 0.5%Cr1.8%, 0%V0.5%, 0%Ni0.5%, to obtain a semi-product, hot rolling the semi-product at a hot rolling starting temperature higher than 1000 C. and cooling the product through air to room temperature to obtain a hot rolled steel part having a microstructure consisting of 70% to 90% of bainite, 5% to 25% of M/A compounds and at most 25% of martensite. The bainite and the M/A compounds contain retained austenite such that the total content of retained austenite in the steel is comprised between 5% and 25%, the carbon content of the retained austenite being comprised between 0.8% and 1.5%.

Disclosed is a method for manufacturing high-carbon bearing steel, which include: heating a billet at a temperature of about 950 to 1,050 C. for about 70 to 120 minutes, rolling the billet to manufacture a wire rod, winding the wire rod to manufacture a wire rod coil, cooling the wire rod coil, and subsequently heat treating the wire rod coil for spheroidizing and carbonitriding, respectively. The bearing steel may include an amount of about 0.9 to 1.3 wt % of carbon (C), an amount of about 1.1 to 1.6 wt % of silicon (Si), an amount of about 1.0 to 1.5 wt % of manganese (Mn), an amount of about 1.5 to 1.9 wt % of chromium (Cr), an amount of about 0.2 to 0.6 wt % of nickel (Ni), an amount of about 0.1 to 0.3 wt % of molybdenum (Mo), and the balance iron (Fe) based on the total weight thereof.

A drawn steel wire has a predetermined chemical composition; in a region of the drawn steel wire that is closer to an axis line than a depth of 100 m from a surface of the drawn steel wire in a lengthwise-section that includes the axis line of the drawn steel wire, a metallographic structure includes 90% or more of a drawn pearlite by an area ratio; in a region of the drawn steel wire that is the depth of 100 m from the surface of the drawn steel wire in the lengthwise-section, the metallographic structure includes 70% or more of the drawn pearlite by the area ratio; when D in units of millimeters represents a diameter of the drawn steel wire, .sub.HV represents a standard deviation of a Vickers hardness of the surface of the drawn steel wire, and Rp.sub.0.2 represents a yield strength of the drawn steel wire, .sub.HV<(9500ln(D)+30000) exp(0.003Rp.sub.0.2) is satisfied, and a tensile strength TS of the drawn steel wire is 1770 MPa or higher.

Embodiments of an ultra-fine-grained, medium carbon steel are disclosed herein. In some embodiments, the ultra-fine grained steel can have high corrosion fatigue resistance, as well as high toughness and yield strength. The ultra-fine grained steels can be advantageous for use as sucker rods in oil wells having corrosive environments.

A spring steel wire includes, by mass %, C: 0.40% to 0.75%, Si: 1.00% to 5.00%, Mn: 0.20% to 2.00%, P: 0.0001% to 0.0500%, S: 0.0001% to 0.0500%, Cr: 0.50% to 3.50%, Al: 0.0005% to 0.0500%, N: 0.0020% to 0.0100%, Mo: 0% to 2.00%, V: 0% to 0.50%, W: 0% to 0.50%, Nb: 0% to 0.100%, Ti: 0% to 0.100%, Ca: 0% to 0.0100%, Mg: 0% to 0.0100%, Zr: 0% to 0.1000%, B: 0% to 0.0100%, Cu: 0% to 1.00%, Ni: 0% to 3.00%, and a remainder consisting of Fe and impurities. A structure includes, by area radio, tempered martensite of 90% or more. The prior austenite grain size number is No. 12.5 or higher. The presence density of iron-based carbide having an equivalent circle diameter ranging from 0.15 m to 0.50 m ranges from 0.40 pieces/m.sup.2 to 2.00 pieces/m.sup.2.

In a rolled steel bar or rolled wire rod for a cold-forged component having a predetermined chemical composition, Y1 represented by Y1=[Mn][Cr] and Y2 represented by Y2=0.134(D/25.4(0.50[C]))/(0.50[C]) satisfy Y1>Y2, the tensile strength is 750 MPa or less, an internal structure is a ferrite-pearlite structure, and the ferrite fraction in the internal structure is 40% or greater. AMOUNT IS 0.30%