The present invention describes a method of dynamical adjustment for manufacturing a thermally treated steel sheet. The method includes: A. a control step, wherein at least one sensor detects a deviation happening during the thermal treatment, B. a calculation step performed when the deviation is detected during the thermal treatment such that a new thermal path TP.sub.target is determined to reach m.sub.target taking the deviation into account, such calculation step including: 1) a calculation substep, wherein at least two thermal path, TP.sub.x corresponding to one microstructure m.sub.x obtained at the end of TP.sub.x, are calculated based on TT and the microstructure m.sub.i of the steel sheet to reach m.sub.target, 2) a selection substep wherein one new thermal path TP.sub.target to reach m.sub.target is selected, TP.sub.target being chosen from said TP.sub.x and being selected such that m.sub.x is the closest to m.sub.target, C. a new thermal treatment step, wherein TP.sub.target is performed online on the steel sheet.

Disclosed are a pressure vessel steel sheet and a method for manufacturing the same, the steel sheet comprising: by wt %, 0.10-0.20% of C, 0.15-0.40% of Si, 1.15-1.50% of Mn, 0.45-0.60% of Mo, 0.03-0.30% of Cu, 0.025% or less of P, 0.025% or less of S and 0.005-0.06% of sol. Al; two or more selected from the group consisting of 0.03-0.30% of Cr, 0.002-0.025% of Nb and 0.002-0.025% of Zr, and the balance of Fe and inevitable impurities, wherein the structure comprises a mixture structure of ferrite, perlite and tempered bainite after post weld heat treatment (PWHT) for 60 hours at 600-660° C., and the area fraction of the tempered bainite is at least 10% (excluding 100%).

A steel for forging mechanical parts including the following elements, expressed in percentage by weight 0.2%≤C≤0.5%; 0.8%≤Mn≤1.5% ; 0.4%≤Si≤1%; 0.15%≤V≤0.6%; 0.01%≤Nb≤0.15%; 0.01%≤Cr≤0.5%; 0.01%≤P≤0.05%; 0.04%≤S≤0.09%; 0.01%≤N≤0.025%; and can contain one or more of the following optional elements 0%≤Al≤0.05%; 0%≤Mo≤0.5%; 0.01%≤Ni≤0.5%; 0%≤Ti≤0.2%; 0%≤B≤0.008%; 0%≤Cu≤0.5%; the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel comprising 50% to 90% of Pearlite, 10% to 40% of Ferrite, with an optional presence of acicular ferrite between 0% and 2%, a niobium equivalent of 80% or more.

A normalizing heat-treated steel sheet having good low-temperature impact toughness and a method for manufacturing the same is provided. The normalizing heat treated steel sheet of the present invention contains, by weight %, C: 0.04 to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0 to 2.0%, Sol. Al: 0.015 to 0.04%, Nb: 0.003 to 0.03%, Ti: 0.005 to 0.02%, Cu: 0.35% or less, Ni: 0.05 to 0.8%, N: 0.002 to 0.008%, P: 0.01% or less (excluding 0%), S: 0.003% or less, and a balance of Fe and unavoidable impurities and has a steel microstructure composed of 70 to 90 area % of polygonal ferrite having a grain size of 20 μm or less, and 10 to 30 area % of spheroidized pearlite.

The rail having a chemical composition containing C: 0.70-0.85 mass %, Si: 0.50-1.60 mass %, Mn: 0.20-1.00 mass %, P: 0.035 mass % or less, S: 0.012 mass % or less, Cr: 0.40-1.30 mass %, the chemical composition satisfying the formula (1)
0.30≤[% Si]/10+[% Mn]/6+[% Cr]/3≤0.55  (1) where [% M] is the content in mass % of the element M,
the balance being Fe and inevitable impurities, where Vickers hardness of a region between positions where a depth from a surface of a rail head of 0.5 and 25 mm is ≥370 HV and <520 HV, a total area ratio of a pearlite microstructure and a bainite microstructure in the region is ≥98%, and an area ratio of the bainite microstructure in the region is >5% and <20%.

Thick high-strength steel having a high yield ratio and excellent durability, and a method for manufacturing same are provided. The thick high-strength steel having a high yield ratio and excellent durability of the present invention comprises, in percentage by weight, C: 0.05 to 0.15%, Si: 0.01 to 1.0%, Mn: 1.0 to 2.3%, Al: 0.01 to 0.1%, Cr: 0.005 to 1.0%, P: 0.001 to 0.05%, S: 0.001 to 0.01%, N: 0.001 to 0.01%, Nb: 0.005 to 0.07%, Ti 0.005 to 0.11%, Fe and unavoidable impurities.

A high-strength steel having excellent low-yield-ratio characteristics, according to one embodiment of the present invention, comprises, by wt %, 0.06-0.12% of C, 0.2-0.5% of Si, 1.5-2.0% of Mn, 0.003-0.05% of Al, 0.01% or less of N, 0.02% or less of P, 0.003% or less of S, 0.05-0.5% of Cr, 0.05-0.5% of Mo, 0.01-0.05% of Nb, 0.0005-0.005% of Ca and the balance of Fe and other inevitable impurities, and comprises polygonal ferrite as a microstructure, wherein the area fraction of the polygonal ferrite is 10-30% and the average hardness of the polygonal ferrite can be 180 Hv or less.

A copper-coated steel wire includes a core wire made of a steel and a coating layer made of copper or a copper alloy which covers an outer peripheral surface of the core wire. The coating layer includes an intermediate layer which is disposed in a region including the interface with the core wire and has a higher zinc concentration than a remaining region of the coating layer.

This hot-rolled steel sheet has a predetermined chemical composition, in which a metallographic structure contains, by area %, less than 3.0% of residual austenite, 15.0% or more and less than 60.0% of ferrite, and less than 5.0% of pearlite, has a ratio L.sub.60/L.sub.7 of a length L.sub.60 of a grain boundary having a crystal misorientation of 60° to a length L.sub.7 of a grain boundary having a crystal misorientation of 7° about a <110> direction of 0.60 or more, has a standard deviation of a Mn concentration of 0.60 mass % or less, and has a tensile strength of 980 MPa or more.

A preparation method of glassless grain-oriented silicon steel includes the following operations. During a decarburization annealing, a thickness of an oxide film on a surface of strip is 1.5-2.5 μm; an atomic weight ratio of Si element and Fe element in the oxide film satisfies: Si/(Si+Fe)≥0.76; during a high-temperature annealing, a cooling stage includes sequentially: cooling with an inner cover when a temperature drops from 1200° C. to 500° C.; wherein a protective gas is a mixed gas containing nitrogen and hydrogen, and a volume percentage of the hydrogen in the mixed gas is >3%; cooling with the inner cover when the temperature drops from 500° C. to 200° C.; wherein the protective gas is nitrogen; and cooling in air by removing the inner cover when the temperature is <200° C.