The steel sheet of the present invention has a steel microstructure containing, in area fraction, martensite: 20% to 100%, ferrite: 0% to 80%, and another metal phase: 5% or less, in which, on a surface of the steel sheet, a ratio of dislocation density in metal phases at a widthwise edge of the steel sheet to dislocation density in the metal phases at a widthwise center of the steel sheet is 100% to 140%, and, at a thicknesswise center of the steel sheet, a ratio of dislocation density in the metal phases at the widthwise edge of the steel sheet to dislocation density in the metal phases at the widthwise center of the steel sheet is 100% to 140%. The maximum amount of warpage of the steel sheet when the steel sheet is sheared to a length of 1 m in a rolling direction is 15 mm or less.

A method of manufacturing a hot-stamped part includes: inserting a blank into a heating furnace including a plurality of sections with different temperature ranges; step heating the blank in multiple stages; and soaking the blank at a temperature of about Ac3 to about 1,000° C., wherein in the step of heating the blank, a temperature condition in the heating furnace satisfies the following equation: 0<(Tg−Ti)/Lt<0.025° C./mm, where Tg denotes a soaking temperature (° C.), Ti denotes an initial temperature (° C.) of the heating furnace, and Lt denotes a length (mm) of step heating sections.

A method for the heat treatment of a part made of maraging steel, which part is obtained by selective laser melting, it comprises the steps of: heating the said part made of maraging steel from ambient temperature T0 to a maximum temperature Tmax of between 600° C. and 640° C., maintaining the said maximum temperature Tmax for a duration of between 5 hours and 7 hours, and rapidly cooling the said part.

Disclosed are a golf putter head having high fault tolerance and a method for manufacturing the same, and a golf putter with the head. The method for manufacturing the golf putter head includes: taking or manufacturing a head body including a ball hitting panel portion, and the ball hitting panel portion including a toe portion, a middle portion, and a heel portion; performing a solution treatment on the ball hitting panel portion; and quenching the toe portion and the heel portion.

A steel sheet has a tensile strength of 1310 MPa or higher, a specified chemical composition, and a steel microstructure containing martensite at an area ratio of 70% or more, bainite at an area ratio of 30% or less, and ferrite and retained austenite at a total area ratio of 10% or less, in which, at a ¼ thickness position of the steel sheet, a number density of carbides having long axes of 0.5 μm or more is 60000 carbides/mm.sup.2 or less, in a ¼-to-¾ thickness region of the steel sheet, a number density of inclusion grains having equivalent circle diameters of 4.0 μm or more is 10 grains/mm.sup.2 or more and 30 grains/mm.sup.2 or less, and, in a surface-to-¼ thickness region of the steel sheet, a number density of inclusion grains having equivalent circle diameters of 4.0 μm or more is 27 grains/mm.sup.2 or less.

Provided are a steel that is for a die and that enables production of a die being for hot working and having both high hardness and high thermal conductivity; a die for hot working; and a manufacturing method for the same. The steel for a hot working die has a compositional makeup containing, in mass %, 0.45-0.65% of C, 0.1-0.6% of Si, 0.1-2.5% of Mn, 1.0-6.0% of Cr, 1.2-3.5% of (Mo+½W) where Mo and W are contained independently or in combination, 0.1-0.5% of V, 0.15-0.6% of Ni, 0.1-0.6% of Cu, and 0.1-0.6% of Al, the balance being Fe and inevitable impurities. Further, this die for hot working has said compositional makeup, and this manufacturing method is for manufacturing said die for hot working.

The disclosure provides a metal surface layer treating method, a metal assembly and an electronic device. The metal surface layer treating method includes: putting metal into a vacuum chamber, and vacuumizing the vacuum chamber to a first vacuum degree; adding a mixed gas of acetylene, nitrogen and hydrogen into the vacuum chamber; and heating the vacuum chamber to a temperature above an ambient temperature. In response to the temperature in the vacuum chamber reaching a first temperature value above the ambient temperature and a gas pressure of the vacuum chamber reaching a first pressure value, performing glow discharge so that a carbon-nitrogen gradient hardening layer is formed on a surface layer of the metal. The method includes removing part of a carbon layer of the surface layer of the carbon-nitrogen gradient hardening layer.

A method of forming a shaped steel object, includes cutting a blank from an alloy composition. The alloy composition includes 0.1-1 wt. % carbon, 0.1-3 wt. % manganese, 0.1-3 wt. % silicon, 1-10 wt. % aluminum, and a balance being iron. The method also includes heating the blank to a temperature above a temperature at which austenite begins to form to generate a heated blank, transferring the heated blank to a die, forming the heated blank into a predetermined shape defined by the die to generate a shaped steel object, and decreasing the temperature of the shaped steel object to ambient temperature. The heating is performed under an atmosphere comprising at least one of an inert gas, a carbon (C)-based gas, and nitrogen (N.sub.2) gas.

A method of forming a shaped steel object is provided. The method includes cutting a blank from an alloy composition including 0.05-0.5 wt. % carbon, 4-12 wt. % manganese, 1-8 wt. % aluminum, 0-0.4 wt. % vanadium, and a remainder balance of iron. The method also includes heating the blank until the blank is austenitized to form a heated blank, transferring the heated blank to a press, forming the heating blank into a predetermined shape to form a stamped object, and decreasing the temperature of the stamped object to a temperature between a martensite start (Ms) temperature of the alloy composition and a martensite final (Mf) temperature of the alloy composition to form a shaped steel object comprising martensite and retained austenite.

A heating station (1) for heating a metal sheet blank (50) and a system comprising such a heating station (1), is herein disclosed. In particular, the heating station comprises lower or upper heating elements (11) arranged in a heating chamber (10) below a metal sheet blank (50) when in a heating position, and configured to provide radiation heating towards the metal sheet blank (50), and a lower mask (14) arranged to block radiation heating from reaching at least a first portion of the metal sheet blank (50), wherein the lower mask (14) comprises a plurality of support projections (14d) projecting from a main surface (14a) of the lower mask (14) towards the metal sheet blank (50) when in a heating position, which support projections (14d) are configured to support a metal sheet blank (50) during heating thereof.