| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a hot-pressed product, by which the strength of the whole product is kept at high level by narrowing hardness changing range while lowering hardness of an after-working portion without bringing about complication and high cost of an apparatus or the like. <P>SOLUTION: The hot-pressed product is obtained through a strain imparting stage where strain is locally imparted to a heated steel sheet, a hot-pressing stage where the steel sheet is formed into a predetermined shape of a product by hot-pressing work after the lapse of a predetermined phase transformation delay time and quenched, hardness lowered parts having low hardness are locally formed in a high hardness part having high hardness, and the post-working stage where shearing is applied to the hardness lowered parts of the press formed product as the post-working. <P>COPYRIGHT: (C)2012,JPO&INPIT |
