| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a formed article by which a press-formed article having portions different in strength, namely, a high strength portion and a low strength portion can be highly accurately produced. SOLUTION: The method for producing a formed article is a method for press-forming a steel sheet into the formed article using a die from a press starting temperature equal to or above an Ar3 point, wherein the steel plate has chemical composition containing, by mass%, 0.08-0.45% C, 0.5-3.0% total of Mn and Cr and the balance comprising Fe, optional additional elements except C, Mn and Cr and inevitable impurities, and has been heated to a temperature of the Ar3 point or higher. The method is characterized in that the formed body having the low strength portion mainly comprising at least either ferritic or bainitic structure and the high strength portion composed of martensitic structure, by controlling bottom dead point holding temperatures of a first portion and a second portion in the steel sheet in the bottom dead point in the press forming, to the different temperatures respectively. COPYRIGHT: (C)2011,JPO&INPIT |
