Methods of selectively cooling and quenching surface regions of high-strength transformation induced plasticity (TRIP) steel are provided. The method may comprise selectively cooling at least one region of an exposed surface of a hot-formed press-hardened component comprising a high-strength steel. Prior to selective cooling, the component has a microstructure comprising about 5% by volume retained austenite in a matrix of martensite. The selective cooling is conducted at a temperature of about 40 C. and forms at least one quenched region comprising about 2% by volume austenite. The TRIP steel may be zinc-coated and having a surface coating comprising zinc and substantially free of liquid metal embrittlement (LME). Zinc-coated hot-formed press-hardened components, including automotive components, formed from such methods are also provided.

Rail-manufacturing equipment that performs forced cooling on at least a head of a hot rail hot-rolled at or heated to the austenite region temperature or higher. The rail-manufacturing equipment includes a head-cooling header configured to jet a cooling medium toward the head of the rail, a head thermometer configured to measure surface temperature of the head of the rail, and a controller configured to adjust jet of the cooling medium from the head-cooling header. The controller includes a temperature-monitoring unit configured to monitor measurement results by the head thermometer during the forced cooling, and a cooling-rate controller.

Rail-manufacturing equipment that performs forced cooling on at least a head of a hot rail hot-rolled at or heated to the austenite region temperature or higher. The rail-manufacturing equipment includes a head-cooling header configured to jet a cooling medium toward the head of the rail, a head thermometer configured to measure surface temperature of the head of the rail, and a controller configured to adjust jet of the cooling medium from the head-cooling header. The controller includes a temperature-monitoring unit configured to monitor measurement results by the head thermometer during the forced cooling, and a cooling-rate controller.

Process and device for cooling a steel strip (1) running through the cooling section (2) of a continuous line, whereby cooling is achieved by projecting the strip with an aqueous solution of formic acid with a concentration of formic acid between 0.1% and 6%, and preferably between 0.5% and 2%.

A seamless steel pipe heat-treatment-finishing-treatment continuous facility includes: a heat treatment apparatus; a steel pipe inspection apparatus which performs a test for a surface defect and/or an inner defect of the seamless steel pipe, the steel pipe inspection apparatus being disposed downstream of the heat treatment apparatus; a main transfer mechanism which forms a main transfer path MT for transferring the seamless steel pipe, discharged from the heat treatment apparatus, to the steel pipe inspection apparatus disposed downstream of the heat treatment apparatus; and a first forced steel pipe-temperature reduction apparatus which forcibly reduces a temperature of the seamless steel pipe on the main transfer path MT, the first forced steel pipe-temperature reduction apparatus being disposed on the main transfer path MT at a position downstream of the heat treatment apparatus and upstream of the steel pipe inspection apparatus.

Disclosed is a hardenable steel composition, hardened steel components made from the same, and methods for forming the same. The steel contains relatively high levels of molybdenum in comparison to chromium, silicon and manganese, with the molybdenum providing an excellent combination of hardness and impact strength in the hardened steel. The steel can be cold formed then reheat-quench hardened with water as the quenching agent with no cracking and optionally no tempering. The steels formed have Vickers hardness levels of over 630 Hv10 (e.g. over 700 Hv10), and impact strengths of over 3 J/cm2 (e.g. over 20 J/cm2).

The stress corrosion cracking resistance of an aluminum alloy member consisting of 7000-series aluminum alloy extruded shape is improved. At least one region of a quenched aluminum alloy extruded shape is subjected to a restoring treatment of heating at a temperature-raising rate of 0.4 C./second or more, holding at a temperature ranging 300 to 590 C. for a time longer than zero second and cooling at a cooling rate of 0.5 C./second or more. A plastic working is applied to the region within 72 hours. The region is subjected to a heat treatment of heating at a temperature-raising rate of 0.4 C./second or more, holding at a temperature ranging 300 to 590 C. for a time longer than zero second and not longer than 300 seconds and cooling at a cooling rate of 2000 C./minute or less. The whole of the aluminum alloy extruded shape is subjected to an artificial aging treatment.

The stress corrosion cracking resistance of an aluminum alloy member consisting of 7000-series aluminum alloy extruded shape is improved. At least one region of a quenched aluminum alloy extruded shape is subjected to a restoring treatment of heating at a temperature-raising rate of 0.4 C./second or more, holding at a temperature ranging 300 to 590 C. for a time longer than zero second and cooling at a cooling rate of 0.5 C./second or more. A plastic working is applied to the region within 72 hours. The region is subjected to a heat treatment of heating at a temperature-raising rate of 0.4 C./second or more, holding at a temperature ranging 300 to 590 C. for a time longer than zero second and not longer than 300 seconds and cooling at a cooling rate of 2000 C./minute or less. The whole of the aluminum alloy extruded shape is subjected to an artificial aging treatment.

A thin steel sheet has a steel structure which has a ferrite area fraction of 30% or less, a bainite area fraction of 5% or less, a martensite and tempered martensite area fraction of 70% or more, and a retained austenite area fraction of 2.0% or less and in which the ratio of the dislocation density in the range of 0 ?m to 20 ?m from a surface of the steel sheet to the dislocation density of a through-thickness central portion of the steel sheet is 90% to 110% and the average of the top 10% of the sizes of cementite grains located in a depth of up to 100 ?m from a surface of the steel sheet is 300 nm or less. The maximum camber of the steel sheet sheared to a length of 1 m in a longitudinal direction of the steel sheet is 15 mm or less.

A high-strength stainless steel seamless pipe for oil country tubular goods has a composition that contains, in mass %, C: 0.012 to 0.05%, Si: 0.05 to 0.50%, Mn: 0.04 to 1.80%, P: 0.030% or less, S: 0.005% or less, Cr: 11.0 to 14.0%, Ni: 0.5 to 6.5%, Mo: 0.5 to 3.0%, Al: 0.005 to 0.10%, V: 0.005 to 0.20%, Co: 0.01 to 0.3%, N: 0.002 to 0.15%, O: 0.010% or less, and Ti: 0.001 to 0.20%, and in which Cr, Ni, Mo, Cu, C, Si, Mn, N, and Ti satisfy predetermined relations, and the balance is Fe and incidental impurities, the high-strength stainless steel seamless pipe having a steel microstructure with 6 to 20% retained austenite in terms of a volume percentage, a yield strength of 758 MPa or more, and an absorption energy vE.sub.?60 at ?60? C. of 70 J or more.