Hot-Dip Sn-Zn Coated Steel Sheet Having Excellent Corrosion Resistance

Abstract

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.

1 - 2 . (canceled) 
   
   
       3 . A hot-dip Sn—Zn coated steel sheet arrangement comprising:
 at least are portion of a steel sheet; and   a hot-dip coating layer formed on a surface of the at least are portion of the steel sheet,   wherein the hot-dip coating layer comprises between about 1 mass % and about 8.8 mass % of Zn,   wherein a remainder of the coating layer comprises between about 91.2 mass % and about 99.0 mass % of Sn and inevitable impurities,   wherein a ratio of a first endothermic value of a first melting heat generated by Sn—Zn eutectic crystals and a second endothermic value of a second melting heat generated by Sn primary crystals in the hot-dip coating layer satisfies the following relationship:
   (the second endothermic value)/{(the second endothermic value)+(the first endothermic value)}≧about 0.3, and 
   wherein a temperature of the second endothermic peak is between about 200° C. and about 230° C., and a temperature of the first endothermic peak is between about 198° C. and about 200° C.   
   
   
       4 . The coated steel sheet of  claim 3 , wherein the hot-dip coating layer comprises between about 4 mass % and about 8.8 mass % of Zn, and wherein a remainder of the hot-dip coating layer comprises between about 91.2 mass % and about 96.0 mass % of Sn and inevitable impurities.