Provided is a steel for a mechanical structure for cold working, which contains C, Si, Mn, P, S, Al and N and in which the metal structure includes pearlite and ferrite, the total areal proportion of pearlite and ferrite relative to the overall structure is 90% or higher, the average circle-equivalent diameter of bcc-Fe crystal grains surrounded by large angle grain boundaries is 5-15 m, the average aspect ratio of pro-eutectoid ferrite crystal grains is 3.0 or lower, and the average spacing at the narrowest pearlite lamellar spacing is 0.20 m or less.

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 steel wire rod according to an aspect of the present invention has a chemical composition in a predetermined range, in which a structure in a central part includes 80 area % to 100 area % of pearlite and a total of 0 area % or more and less than 20 area % of proeutectoid ferrite, proeutectoid cementite, martensite, and bainite; an average lamellar spacing of the pearlite in the central part is 50 nm to 100 nm; an average length of lamellar cementite in the central part is 1.9 m or less; an average pearlite block size in the central part is 15.0 m to 30.0 m; a structure in a surface part includes 70 area % to 100 area % of the pearlite; and an average pearlite block size in the surface part is 0.40 times or more and 0.87 times or less the average pearlite block size in the central part.

A cold rolled steel wire having the following chemical composition expressed in percent by weight, 0.2C %0.6, 0.5Mn %1.0, 0.1Si0.5%, 0.2Cr1.0%, P0.020%, S0.015%, N0.010%, and optionally not more than 0.07% Al, not more than 0.2% Ni, not more than 0.1% Mo and not more than 0.1% Cu, the balance being iron and the unavoidable impurities due to processing. This wire has a microstructure including bainite and, optionally, up to 35% acicular ferrite and up to 15% pearlite. A fabrication method and flexible conduits for hydrocarbon extraction are also provided.

A cold rolled steel wire having the following chemical composition expressed in percent by weight, 0.2C %0.6, 0.5Mn %1.0, 0.1Si0.5%, 0.2Cr1.0%, P0.020%, S0.015%, N0.010%, and optionally not more than 0.07% Al, not more than 0.2% Ni, not more than 0.1% Mo and not more than 0.1% Cu, the balance being iron and the unavoidable impurities due to processing. This wire has a microstructure including bainite and, optionally, up to 35% acicular ferrite and up to 15% pearlite. A fabrication method and flexible conduits for hydrocarbon extraction are also provided.

A method for producing long metal products includes the steps of receiving long intermediate products traveling on respective continuous casting lines, to an exit area, and subsequently introducing products from the exit area into a production plant having known layout parameters; the production plant has a rolling mill for rolling the products; interconnected production lines between the exit area of the casting machine and the rolling mill, the production lines define production paths or routes; and a first and a second heating devices. The method associates a mathematical model to the production plant for dynamically calculating a reference value, or Global Heating Cost Index, correlated to heating devices; automatically determining for the intermediate products the production path or route that minimizes the reference value, or Global Heating Cost Index; and eventually automatically routing each of the products along the determined production path which minimizes the reference value, or Global Heating Cost Index.

A steel contains, in a chemical composition, C, Si, Mn, and Al, and contains pearlite as a metallographic structure, and a value obtained by dividing an Mn content in a cementite in the pearlite in terms of at % by an Mn content in a ferrite in the pearlite in terms of at % is higher than 0 and equal to or lower than 5.0.

The present invention discloses a method for manufacturing a low-carbon nitrogen-containing austenitic stainless steel bar, which sequentially includes the following steps: smelting, electroslag remelting and forging; in the electroslag remelting process, the steel ingot obtained in the smelting process is used as an electrode bar of an electroslag furnace, remelting with specific slag and crystallizing; in the forging process, forging the crystallized steel ingot into a material by a specific forging method; the specific slag comprises CaF.sub.2 (65-70%), Al.sub.2O.sub.3 (15-20%), CaO (5-10%) and MgO (2-5%) in percentage by weight; specific forging methods include upsetting-and-drawing and radial forging, wherein the upsetting-and-drawing includes: a pass deformation is less than 35%, a pass reduction is 50-80 mm, a pass heating temperature is 1130-1150 C., and a pass deformation method is ellipse-ellipse-circle. The method can obtain the low-carbon high-strength nitrogen-containing austenitic stainless steel with uniformly distributed chemical composition and tissues, high purity and high strength.

A method for producing a further wire, wherein the method includes, providing a first wire and feeding the first wire through a furnace to obtain the further wire. A further cast of the further wire is larger than a first cast of the first wire.

A method for laser beam hardening of sections to be hardened (A) of a card wire (10) is disclosed. Thereby the card wire (10) is moved in a conveying direction through a working space (26). In the working space (26), an inert gas atmosphere is created by continuously or discontinuously introducing inert gas (G). In the working space (26), a laser beam area (27) is generated through which the sections to be hardened (A) of the card wire (10) are moved. Thereby the sections to be hardened (A) are heated. After exiting out of the laser beam area (27) the sections to be hardened (A) cool and are hardened by progressing through this temperature profile. The hardening in the inert gas atmosphere inside working space (26) avoids formation of oxide layers (scaling) and annealing colors.