Hyundai Steel Company

A hot stamping component according to an embodiment of the present disclosure includes a steel sheet, a plating layer located on the steel sheet and including Zn, and a surface layer located on the plating layer, wherein the surface layer includes a post-treatment layer including an Si-based inorganic post-treatment agent, a Zn oxide layer located on a same layer as the post-treatment layer on the plating layer, and an inter-diffusion layer located between the plating layer and at least one of the post-treatment layer and the Zn oxide layer to overlap at least one of the post-treatment layer and the Zn oxide layer, the inter-diffusion layer including at least one of Si, Mn, O, Fe, Zn, and SiO, wherein a tensile strength of the steel sheet is 1680 MPa or more.

In one aspect, the present disclosure relates to a non-oriented electrical steel sheet and a method for manufacturing the same. Preferred e non-oriented electrical steel sheets and methods for manufacturing the same can provide minimized deformation of the steel sheet during heat treatment that can suppress an increase in iron loss, and thus excellent magnetic properties can be achieved.

The present disclosure relates to a fuel cell separator having corrosion resistance and high conductivity, and a fuel cell separator coating method, and provides a fuel cell separator comprising: a metal substrate; and a coating layer which is formed on the metal substrate, and which is composed of a mixture of a binder resin and a filler comprising a flake-like carbon material and a granular carbon material, wherein the filler is encompassed by the binder resin so as to be dispersed inside the coating layer, and the filler is exposed to the outside on the surface of the coating layer.

In one aspect, disclosed is a method for manufacturing non-oriented electrical steel sheets with excellent magnetic properties and the non-oriented electrical steel sheets produced thereby. In a specific embodiment, the method for manufacturing non-oriented electrical steel sheets with excellent magnetic properties includes the steps of: manufacturing a hot-rolled steel sheet using a slab containing 0.4-3.5 wt % of silicon (Si), 0 (exclusive) to 0.05 wt % (inclusive) of aluminum (Al), 0.002-3.5 wt % of austenite stabilizing elements, and the balance of iron (Fe) and other inevitable impurities; cold rolling the hot-rolled steel sheet to prepare a cold-rolled steel sheet; and cold-annealing the cold-rolled steel sheet, wherein the cold-annealing includes a primary heat treatment step of heating and maintaining the cold-rolled steel sheet up to the temperature of the austenite single-phase region; and a secondary heat treatment step of cooling and maintaining the primary heat-treated cold-rolled steel sheet down to the temperature of the ferrite and austenite dual-phase region.

A steel section manufacturing method, according to one embodiment of the present invention, comprises the steps of: (a) reheating steel at a temperature of 1200° C. or higher, the steel comprising 0.17% by weight or less of carbon (C), 1.6% by weight or less of manganese (Mn), 0.10-0.35% by weight of chromium (Cr), 0.15% by weight or less of molybdenum (Mo), 0.05% by weight or less of niobium (Nb), 0.003% by weight or less of boron (B), 0.04% by weight or less of titanium (Ti), and the remainder being iron (Fe) and other inevitable impurities; (b) hot rolling the steel and controlling the rolling start temperature to 1050-1100° C. and the rolling end temperature to 860-930° C.; and (c) water cooling the steel. Thereby, it is possible to implement a high-performance steel section and a steel section manufacturing method which simultaneously have earthquake-resistant performance fire-resistant performance.

The present invention provides a cold-rolled steel sheet including 0.15 to 0.20% by weight of carbon (C), 1.0 to 2.0% by weight of silicon (Si), 1.5 to 3.0% by weight of manganese (Mn), greater than 0% by weight and 0.02% by weight or less of phosphorus (P), greater than 0% by weight and 0.003% by weight or less of sulfur (S), 0.01 to 0.3% by weight of aluminum (Al), greater than 0% by weight and 0.01% by weight or less of nitrogen (N), 48/14·[N] to 0.1% by weight of titanium (Ti) ([N] is a content (% by weight) of nitrogen), remaining iron (Fe), and other unavoidable impurities, wherein a final microstructure of the cold-rolled steel sheet consists of ferrite, needle-shaped residual austenite, a martensite/austenite composite structure, and block-shaped martensite; the area fraction of the ferrite may be 30 to 60%, the area fraction of the needle-shaped residual austenite may be 5 to 12%, the area fraction of the martensite/austenite composite structure may be 25 to 50%, and the area fraction of the block-shaped martensite may be 5 to 12%; and an amount of carbon concentrated in residual austenite may be 1.1% by weight or more.

A method for manufacturing steel according to an embodiment of the present invention comprises the steps of: preparing a first molten metal manufactured using a first raw material including iron ore and a second molten metal manufactured using a second raw material including iron scrap; mixing the first molten metal and the second molten metal to manufacture a third molten metal; adjusting components of the third molten metal to manufacture a fourth molten metal; and manufacturing a product by processing the fourth molten metal.

The present disclosure relates to a material analysis method which may comprise the steps of: (a) preparing a specimen for structure analysis; (b) training an artificial intelligence model with training images labelled with structural aspects of arbitrary specimens; (c) analyzing a plurality of images for analysis not labelled with structural aspects of specimens by using the trained artificial intelligence model, and removing images for analysis classified as preset noise structural aspects; and (d) using the trained artificial intelligence model to analyze the images for analysis that remain after the images for analysis classified as the noise structural aspects are removed, and classifying the remaining images for analysis as at least one target structural aspect.

A center pillar outer part for a vehicle and a method for manufacturing the same are disclosed. The center pillar outer part for the vehicle includes an upper blank, a middle blank, and a lower blank made of different materials. The middle blank and the lower blank are joined through a laser welding to form a laser welded blank (LWB), and the upper blank and the LWB are joined through a spot welding and then formed into an integral structure through a hot stamping method.

One embodiment of the present invention discloses a member for automobile structure including a base steel sheet and a plating layer covering at least one surface of the base steel sheet, wherein the member for automobile structure has a tensile strength of 1350 MPa or greater and a yield strength of 900 MPa or greater, wherein the base steel sheet includes a martensite phase having an area fraction of 80% or greater, an iron-based carbide located inside the martensite phase and having an area fraction of less than 5% based on the martensite phase, and precipitates distributed inside the base steel sheet, wherein a mismatch dislocation exists at the interface between iron and the precipitates of the base steel sheet, and a difference between lattice constants of the iron and the precipitates is less than 25% of the lattice constants of the iron.