Posco

Research Institute of Industrial Science & Technology

Other

Noi-Ha Cho

Eel-Young Kim

Jung-Sik Lee

Jae-Young Lee

Jin-Gun Sohn

Yong-Min Kim

Young-Jin Kwak

Soon-Joo Kwon

Sang-Heon Kim

Won-Ho Son

Yeong-Sool Jin

Jeong-Bong Yoon

Jae-Eok Cho

Jin-Tae Kim

Ki-Bong Kang

Ki-Duck Park

Ji-Eun Oh

A cold rolled steel sheet, and a method of manufacturing the same, designed to have aging resistance and excellent formability suitable for use in automobile bodies, electronic appliances, and the like. The cold rolled steel sheet comprises in weight %: 0.003% or less of C, 0.003&#x2dc;0.03% of S, 0.01&#x2dc;0.1% of Al, 0.02% or less of N, 0.2% or less of P, at least one of 0.03&#x2dc;0.2% of Mn and 0.005&#x2dc;0.2% of Cu, and a balance of Fe and other unavoidable impurities. When the steel sheet comprises one of Mn and Cu, the composition of Mn, Cu, and S satisfies at least one relationship: 0.58*Mn/S&#x2266;10 and 1&#x2266;0.5*Cu/S&#x2266;10, and when the steel sheet comprises both Mn and Cu, the composition of Mn, Cu, and S satisfies the relationship: Mn+Cu&#x2266;0.3 and 2&#x2266;0.5*(Mn+Cu)/S&#x2266;20. Participates of MnS, CuS, and (Mn, Cu)S in the steel sheet have an average size of 0.2 &#x3bc;m or less. Since carbon content in a solid solution state in a crystal grain is controlled by fine precipitates of MnS, CuS, or (Mn, Cu)S, the steel sheet has enhanced aging resistance and formability, and has excellent yield strength and strength-ductility.

Cold rolled steel sheet having aging resistance and superior formability, and process for producing the same

A spangle-free, hot-dip galvanized steel sheet, and a method and device for manufacturing the same. The hot-dip galvanized steel sheet is characterized in that a solidified zinc crystal of hot-dip galvanized layer has an average crystalline texture particle diameter of 10 to 88 &#x3bc;m and there is no solidification traces of dendrites upon observing under a microscope at a magnification of 100&#xd7;. The method comprises dipping a steel sheet in a bath of a zinc-coating solution containing 0.13 to 0.3% by weight of aluminum; air-wiping the steel sheet to remove an excess of the coating solution; spraying water or an aqueous solution on the air-wiped steel sheet, using a steel sheet temperature in the range of a hot-dip galvanization temperature to 419 &#xb0; C. as a spray initiation temperature and using a steel sheet temperature in the range of 417 &#xb0; C. to 415 &#xb0; C. as a spray completion temperature; passing sprayed liquid droplets of water or aqueous solution through a mesh-like high-voltage charged electrode which is electrically charged with a high voltage of &#x2212;1 to &#x2212;50 kV; and allowing the electrode-passed liquid droplets to be bound to the surface of the steel sheet and hereby being served as solidification nuclei of molten zinc.

Method of manufacturing hot-dipped galvanized steel sheet

The steel plate is manufactured from a composition comprising C, N and S in an amount of 0.0150% by weight or less in total; Mn in an amount of 0.2 to 0.8% by weight; Al inan amount of 0.6% by weight or less; Si in an amount of 0.4% by weight or less; Cu and/or Sn in an amount of 0.1 to 0.6% by weight in total; and Fe for the remainder, and inevitably present elements, whereby the steel plate can show excellent electromagnetic shield effect and hot-dip galvanization properties.

High strength steel plate having superior electromagnetic shielding and hot-dip galvanizing properties

A steel plate and a hot-dip galvanized steel plate, superior in terms of high electromagnetic shield capacity. The steel plate is prepared from a composition comprising C, N and S in an amount of 0.150% by weight or less in total; Mn in an amount of 0.1 to 1.0% by weight; Si in an amount of 0.5% by weight or less; Al in an amount of 1.0% by weight or less; P in an amount of 0.06% by weight or less; and Fe for the remainder, and inevitable elements, and shows a yield strength of 18 kg/mm2 or higher, and an elongation of 40% or higher. The hot-dip galvanized steel plate is prepared from a composition comprising C, N and S in an amount of 0.0150 % by weight or less in total; Mn in an amount of 0.2 to 0.8% by weight; Al in an amount of 0.6% by weight or less; Si in an amount of 0.4% by weight or less; P in an amount of 0.06% by weight or less, with the proviso that the sum of Mn, Al, Si and P amounts to 0.2-1.0% by weight; and Fe for the remainder, and inevitably present elements. In addition to having high yield strength, the hot-dip galvanized steel plate is resistant to corrosion owing to the coating of a corrosion-resistant element on the surface.

Steel plate and a hot dip galvanizing steel plate having superior electric and magnetic shielding property

Disclosed are far-infrared emission powders and resin-coated steel plates with antibacterial activity and far-infrared emission properties. In addition to being 0.9 or higher in emissivity, the far-infrared emission powders are inhibitory against the growth of bacteria, with a pH value of 7.5-10.5 in its saturate aqueous solution. A coating material comprising 5-100 parts by weight of the powder per 100 parts by weight of a resin is coated to a dry thickness of 5-60 &mgr;m on an electromagnetic shield steel plate without interruption of the intrinsic electromagnetic shield properties of the steel plate.

Far-infrared emission powder with antibacterial activity and bio-wave steel plate coated with resin containing same

Growing community of inventors

Pohang-si, South Korea

Noi-Ha Cho