Nippon Steel Corporation, Yawata Works Patent applications |
Patent application number | Title | Published |
20100151117 | HOT-DIP Sn-Zn COATED STEEL SHEET HAVING EXCELLENT CORROSION RESISTANCE - An exemplary embodiment of manufacturing a hot-dip Sn—Zn coated steel sheet is provided which can include pre-coating a Fe—Ni alloy containing between about 10 to 80 mass % of Ni, and a remainder being Fe on a steel sheet, immersing the steel sheet into a Sn—Zn hot-dip coating bath so as to form a hot-dip coating layer on the steel sheet, cooling the hot-dip coating layer at a cooling rate of about 10° C./sec to about 30° C./sec so as to obtain a hot-dip Sn—Zn coated steel sheet, measuring a differential scanning calorimetric curve of the hot-dip Sn—Zn coated steel sheet by a differential scanning calorimetry, and distinguishing whether the hot-dip Sn—Zn coated steel sheet has an objective microstructure by the measured differential scanning calorimetric curve. | 06-17-2010 |
20090047542 | Hot-Dip Sn-Zn Coated Steel Sheet Having Excellent Corrosion Resistance - An exemplary embodiment of a hot-dip Sn—Zn coated steel sheet is provided which can include a steel sheet and a hot-dip coating layer which is formed on a surface of the steel sheet. The coating layer can contain between about 1 mass % and about 8.8 mass % of Zn, and a remainder including between about 91.2 mass % and about 99.0 mass % of Sn and inevitable impurities. A ratio of an endothermic value of melting heat generated by Sn—Zn eutectic crystals and an endothermic value of melting heat generated by Sn primary crystals in the hot-dip coating layer can satisfy the following relationship: (endothermic value of melting heat generated by Sn primary crystals)/{(endothermic value of melting heat generated by Sn primary crystals)+(endothermic value of melting heat generated by Sn—Zn eutectic crystals)}≧about 0.3. Further, a temperature of an endothermic peak generated by melting of the Sn primary crystals can be between about 200° C. and about 230° C., and a temperature of an endothermic peak generated by melting of the Sn—Zn eutectic crystals may be between about 198° C. and about 200° C. | 02-19-2009 |