A bolt of the present invention has a composition comprising: 0.50 mass % or greater and 0.65 mass % or less of carbon (C), 1.5 mass % or greater and 2.5 mass % or less of silicon (Si), 1.0 mass % or greater and 2.0 mass % or less of chromium (Cr), 0.2 mass % or greater and 1.0 mass % or less of manganese (Mn), 1.5 mass % or greater and 5.0 mass % or less of molybdenum (Mo), wherein a total amount of phosphorous (P) and sulfur (S) as impurities is 0.03 mass % or less, the remaining is iron (Fe), and the bolt comprises an iron based oxide film with a film thickness of 3 m or greater and 20 m or less on the surface thereof. The bolt has excellent delayed fracture resistance and reliably provides a fastening axial force.

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.

The present invention relates to the technical field of manufacturing of metal materials, and in particular to a 7000-series aluminum alloy wire for additive manufacturing and a preparation method thereof. The wire was prepared by subjecting an AlTiB intermediate alloy containing TiB.sub.2 particles generated in situ to severe plastic deformation to obtain an intermediate alloy containing TiB.sub.2 nanoparticles having a particle size of 50-1,000 nm or a mixture of two different particles; using the intermediate alloy containing TiB.sub.2 nanoparticles as a matrix raw material, adding other metal or intermediate alloy for smelting to obtain an alloy melt; preparing a wire blank with the alloy melt; subjecting the wire blank to hot rolling, drawing, intermediate annealing and surface treatment to obtain an AlZnMgCu alloy wire reinforced by particles at nano scale or submicron scale.

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.

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%

A nickel -titanium alloy is made to be wholly or substantially free of titanium-rich oxide inclusions by including yttrium in an amount up to 0.15 wt. %, with the balance of the alloy being nickel and titanium in approximately equal proportion. For example, a NiTiY alloy may have a composition including, in weight percent based on total alloy weight: between 50 and 60 wt. % nickel; between 40 and 50 wt. % titanium; and between 0.01 and 0.15 wt. % yttrium. The resulting alloy is capable of being drawn into various forms, e.g., fine medical-grade wire, without exhibiting an unacceptable tendency to develop surface defects or to fracture or crack during cold drawing or forging. The resulting final forms exhibit favorable fatigue strength and fatigue-resistant characteristics.

Aluminum alloy wires with improved electrical conductivity and improved ultimate tensile strength are disclosed. The aluminum alloys include magnesium, silicon, and copper and are formed without a solution heat treatment. The aluminum alloy wires are useful as conductors for overhead transmission lines. Methods of making the aluminum alloy wires are further disclosed.