Provided is a wiredrawn product drawn from a heat-treated steel containing: 0.38 to 1.05% by mass of C; 0.0 to 1.0% by mass of Mn; 0.0 to 0.50% by mass of Cr; and 0.0 to 1.5% by mass of Si, with the remainder being Fe and unavoidable impurities, wherein a GOS value/average crystal grain size is greater than or equal to ?0.6?GAM value+1.5 at a grain boundary setting angle of 2? and a step number of 0.07 ?m.

A system for the thermomechanical rolling of long semi-finished steel products includes a first rolling unit; a second rolling unit, arranged downstream of the first rolling unit; a first thermomechanical sizing block, arranged downstream of the second rolling unit; a second cooling device, arranged between the second rolling unit and the first thermomechanical sizing block; a cooling-bed, ring-laying and/or coil-winding device, arranged downstream of the first thermomechanical sizing block; a third cooling device, arranged between the first thermomechanical sizing block and the cooling-bed, ring-laying and/or coil-winding device; and a structure-sensor device, which is arranged between the first thermomechanical sizing block and the cooling-bed, ring-laying and/or coil-winding device, and can be used for determining directly in the ongoing process a martensitic structure, in particular a proportion of martensite in percent by area, in the thermomechanically rolled long semi-finished steel product or in the steel product.

The present invention provides a medium-carbon boron-containing steel. The chemical components of the medium-carbon boron-containing steel are as follows in mass percentage: 0.37-0.45% of C; 0.17-0.37% of Si; 0.60-0.90% of Mn; 0.020-0.060% of Al; 0.0008-0.0035% of B; 0.030-0.060% of Ti; P?0.025%; S?0.025%; Cr?0.25%; Ni?0.20%; Mo?0.10%; Cu?0.20%; and the remainder is Fe and inevitable impurities. The controlled rolling and controlled cooling method suitable for the on-line normalizing treatment of medium-carbon boron-containing steel sequentially comprises the following steps: heating, rough rolling, finishing rolling, cooling by passing through water, and cold bed slow cooling. The medium-carbon boron-containing steel can meet the requirements of having a hardness of 190-220 HBW, an actual grain size that is ?7 grade, and a banded structure that is ?2 grade.

Disclosed are a wire rod and a steel wire for a spring, a spring with improved strength and fatigue limit, and a method for manufacturing the same.

The disclosed wire rod for a spring with improved strength and fatigue limit according to an embodiment includes, in percent by weight (wt %): 0.6 to 0.7% of C, 2.0 to 2.5% of Si, 0.2 to 0.7% of Mn, 0.9 to 1.5% of Cr, 0.015% or less of P, 0.01% or less of S, 0.01% or less of Al, 0.01% or less of N, 0.25% or less of Mo, 0.25% or less of W, 0.05% to 0.2% of V, 0.05% or less of Nb, and the balance of Fe and unavoidable impurities, wherein Mn+Cr?1.8% and 0.05 at %?Mo+W?0.15 at % may be satisfied.

A method for the heat treatment of a steel reinforcing element (F) for a tire, comprises a step of reducing the temperature of the reinforcing element by continuous cooling: from an initial temperature of the austenite range, to a final temperature of the ferrite-pearlite range, passing through at least one transformation range of the steel, the transformation range(s) being distinct from the bainite range. The temperature reduction step comprises a transformation (C2, C3) from the austenitic microstructure to the ferritic-pearlitic microstructure. The temperature of the reinforcing element is strictly decreasing during the reduction step. The mean rate of temperature reduction during the transformation (C2, C3) of the steel microstructure is greater than or equal to 30 C..Math.s.sup.1 and less than or equal to 110 C..Math.s.sup.1.

A filament according to an aspect of the present invention includes a predetermined chemical composition, in which a diameter r of the filament is 0.15 mm to 0.35 mm, a soft portion is formed along an outer circumference of the filament, the Vickers hardness of the soft portion is lower than that of a position of the filament at a depth of of the diameter r by Hv 50 or higher, the thickness of the soft portion is 1 m to 0.1r mm, the metallographic structure of a center portion of the filament contains 95% to 100% of pearlite by area %, the average lamellar spacing of pearlite in a portion from a surface of the filament to a depth of 1 m is less than that of pearlite at the center of the filament, the difference between the average lamellar spacing of pearlite in the portion from the surface of the filament to the depth of 1 m and the average lamellar spacing of pearlite at the center of the filament is 2.0 nm or less, and the tensile strength is 3200 MPa or higher.

To provide a heat-treated steel excellent in both tensile strength and toughness.

A heat-treated steel contains 0.38 to 1.05% by mass of C, 0.0 to 1.0% by mass of Mn, 0.0 to 0.50% by mass of Cr, and 0.0 to 1.5% by mass of Si with the remainder being Fe and unavoidable impurities, wherein an average crystal grain size at a grain boundary setting angle of 15 is 10C+7 (m) or less (wherein, C represents a carbon content (%)).

The present disclosure relates to a steel wire rod enabling the omission of softening heat treatment and a method of manufacturing same. An embodiment of the present disclosure provides a steel wire rod enabling the omission of softening heat treatment and a method of manufacturing same, the steel wire rod comprising, in weight %, 0.2-0.45% of C, 0.02-0.4% of Si, 0.3-1.5% of Mn, 0.01-1.5% of Cr, 0.02-0.05% of Al, 0.01-0.5% of Mo, 0.01% or less of N, and the balance Fe and other unavoidable impurities, wherein the microstructure of the steel wire rod is a composite structure of proeutectoid ferrite+perlite as a main phase; the steel wire rod contains 10 area % or less (including 0%) of at least one of bainite or martensite; and the average colony size of the perlite is 5 m or less.

A method of hardening a clothing wire for processing textile fibres and to an apparatus system therefor. The clothing wire has a succession of teeth arranged in its longitudinal direction, and the clothing wire is guided through a heating region in a pass-through direction for contact with at least one open flame. The heating region is followed by a quenching bath having a quenching liquid and by a subsequent tempering apparatus. The clothing wire moving in the pass-through direction is flushed around with a protective medium in a transition region between the region of contact with the open flame and the entry into the quenching liquid.

A method for the heat treatment of a steel reinforcing element (F) for a tire, comprises a step of reducing the temperature of the reinforcing element by continuous cooling: from an initial temperature of the austenite range, to a final temperature of the ferrite-pearlite range, passing through at least one transformation range of the steel, the transformation range(s) being distinct from the bainite range. The temperature reduction step comprises a transformation (C2, C3) from the austenitic microstructure to the ferritic-pearlitic microstructure. The temperature of the reinforcing element is strictly decreasing during the reduction step. The mean rate of temperature reduction during the transformation (C2, C3) of the steel microstructure is greater than or equal to 30 C..Math.s.sup.1 and less than or equal to 110 C..Math.s.sup.1.