A high strength galvanized steel sheet has a composition including, C: 0.02% or more and 0.30% or less, Si: 0.01% or more and 2.5% or less, Mn: 0.1% or more and 3.0% or less, P: 0.003% or more and 0.08% or less, S: 0.01% or less, Al: 0.001% or more and 0.20% or less, Ti: 0.03% or more and 0.40% or less and the balance being Fe and inevitable impurities, and a zinc-coated layer having a coating weight per surface of 20 g/m.sup.2 or more and 120 g/m.sup.2 or less. The concentration ratio of C to Ti (C/Ti) in a portion within 10 μm from the surface of the base steel sheet is 0.8 or more and 1.5 or less, and the total amount of oxides of one or more selected from Fe, Si, Mn, P, Al and Ti formed in a surface portion within 100 μm from the surface of the base steel sheet is 0.05 g/m.sup.2 or less.

A high-strength thick-walled electric resistance welded steel pipe has excellent low-temperature toughness and excellent HIC resistance and a yield strength of 400 MPa or more. The steel has a chemical composition consisting of C: 0.025% to 0.084%, Si: 0.10% to 0.30%, Mn: 0.70% to 1.80%, controlled amounts of P, S, Al, N, and O, Nb: 0.001% to 0.065%, V: 0.001% to 0.065%, Ti: 0.001% to 0.033%, and Ca: 0.0001% to 0.0035% on a mass percent basis and the remainder being Fe and incidental impurities, and satisfies Pcm of 0.20 or less.

Improved steel compositions and methods of making the same are provided. More particularly, the present disclosure provides high manganese (Mn) steel having enhanced strength and/or performance at cryogenic temperatures, and methods for fabricating high manganese steel compositions having enhanced strength and/or performance at cryogenic temperatures. The advantageous steel compositions/components of the present disclosure improve one or more of the following properties: strength, toughness, elastic modulus, thermal expansion coefficient and/or thermal conductivity. In general, the present disclosure provides high manganese steels tailored to resist wear and/or deformation at cryogenic temperatures.

A hot-stamping formed body has a predetermined chemical composition and a microstructure including, by area ratio, 90% to 100% of martensite and 0% to 10% of a remainder in the microstructure. In the microstructure, a region in which an average GAIQ value in a unit grain is 60,000 or more is 30 area % or more, and a number density of carbides having a circle equivalent diameter of 0.20 μm or more is 50/mm.sup.2 or less.

A method of manufacturing an energy absorbing component for a vehicle is provided. The method includes heating a bainitic GENS steel material which has a microstructure including ferrite and bainite to a temperature above the Ac3 temperature to convert a portion of the ferrite and bainite to austenite. The method further includes forming while cooling the heated steel blank into a component in a temperature controlled steel die. During the cooling step, the steel material is cooled to a temperature below the Ms temperature to form retained austenite. A portion of the austenite transforms to martensite and bainite during the forming and cooling step. The method can further include heating the component to a temperature above the Ms temperature after the forming and cooling step to increase energy absorption characteristics. During a crash event, the strain imposed on the component converts retained austenite present in the component to martensite.

An H-section steel has a predetermined chemical composition in which a thickness of a flange is 100 mm to 150 mm, at a strength evaluation position an area fraction of bainite in a steel structure is 80% or more, yield strength or 0.2% proof strength is 450 MPa or more, tensile strength is 550 MPa or more and 680 MPa or less, at a toughness evaluation position an average austenite grain size in the steel structure is 150 μm or less, and (Mg, Mn)S having a particle size of 0.005 μm to 0.5 μm is included at a density of 1.0×10.sup.5 pieces/mm.sup.2 to 1.0×10.sup.7 pieces/mm.sup.2.

An H-section steel has a predetermined chemical composition in which a thickness of a flange is 100 mm to 150 mm, at a strength evaluation position an area fraction of bainite in a steel structure is 80% or more, yield strength or 0.2% proof strength is 450 MPa or more, tensile strength is 550 MPa or more and 680 MPa or less, at a toughness evaluation position an average austenite grain size in the steel structure is 150 μm or less, and (Mg, Mn)S having a particle size of 0.005 μm to 0.5 μm is included at a density of 1.0×10.sup.5 pieces/mm.sup.2 to 1.0×10.sup.7 pieces/mm.sup.2.

Provided is a hot-working tool capable of maintaining adequate toughness even if the permissible amount of P contained in the hot-working tool is increased. The present invention is a hot-working tool, which has a component composition that can be adjusted to a martensitic structure by quenching and has a post-quenching and tempering martensitic structure, wherein: the component composition comprises greater than 0.020 mass % to 0.050 mass % of P; prior austenite grain diameter in said post-quenching and tempering martensitic structure is at least No. 9.5 in grain size number according to JIS-G-0551; and the P concentration of the grain boundary of said prior austenite particles is not more than 1.5 mass %. A hot-working tool wherein said component composition also comprises not more than 0.0250 mass % of Zn is preferable. The present invention also is a method for manufacturing a hot-working tool in which quenching and tempering are performed on a hot-working tool material with said component composition.

A method for producing an alloy steel composition includes the following steps: performing a first heat treatment on an alloy steel composition and maintaining for a first time period to soften the alloy steel composition; performing a first cooling treatment on the softened alloy steel composition; performing a treatment on the softened the alloy steel composition to form a workpiece; performing a second heat treatment on the workpiece and maintaining for a second time period; and performing a second cooling treatment on the workpiece to make the workpiece become to be a Bainite structure, and a cooling rate of the second cooling treatment is high than the cooling rate of the first cooling treatment.

The object of the present invention is to provide a metal plate capable of manufacturing a deposition mask in which dispersion of positions of through-holes is restrained. A thermal recovery rate is defined as parts per million of a difference a distance between to measurement points on a sample before a heat treatment and a distance therebetween after the heat treatment, relative to the distance therebetween before the heat treatment. In this case, an average value of the thermal recovery rates of the respective samples is not less than −10 ppm and not more than +10 ppm, and (2) a dispersion of the thermal recovery rates of the respective samples is not more than 20 ppm.