| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hot-dip Sn-Zn coated steel sheet having excellent characteristics in corrosion resistance, formability, and weldability with good balance therebetween, without using Pb. <P>SOLUTION: The hot-dip Sn-Zn coated steel sheet comprises a steel sheet and a hot-dip coating layer which is formed on the surface of the steel sheet and comprises 1 to 8.8 mass% of Zn and a remainder composed of 91.2 to 99.0 mass% of Sn and impurities, wherein the ratio of the endothermic value produced by the Sn-Zn eutectic crystal melting heat and the endothermic value produced by the Sn primary crystal melting heat in the hot-dip coating layer satisfies the following formula: (endothermic value produced by Sn primary crystal melting)/ä(endothermic value produced by Sn primary crystal melting)+(endothermic value produced by Sn-Zn eutectic crystal melting)}≥0.3; and the temperature of endothermic peak temperature produced by the Sn primary crystal melting is not lower than 200°C and not higher than 230°C or lower and that produced by the Sn-Zn eutectic crystal melting is not lower than 198°C and lower than 200°C. <P>COPYRIGHT: (C)2012,JPO&INPIT |
