| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To manufacture a high-strength steel sheet having adequate characteristics at a utilization time, by forming such fine crystal grains as to impart the steel an adequate strength-ductility balance, weldability, toughness and plating properties, and further be maintained even when the temperature is elevated by plating or welding, while reducing an adding quantity of alloys that increase the manufacturing cost. <P>SOLUTION: The high-strength steel sheet superior in the formability and the toughness has grain sizes of a ferrite phase in the metallographic structure adjusted to 5.0μm or smaller, by containing 0.05-4.0% N, Mn controlled to 10.0% or less, Si and Al each controlled to 4.0% or less, and Ti, Nb, B or the like as needed in order to control formation of nitrides, while not absolutely requiring Cr and Ni. <P>COPYRIGHT: (C)2004,JPO</p> |
