| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot press formed product having different strength parts, i.e., a high strength part and a low strength part.SOLUTION: A hot press formed product made of a steel plate having a chemical composition including C:0.10-0.33%, Mn and Cr: 0.5-2.0% in total, B:0.0010-0.010%, and Ti: 0.01-0.10%, comprises: a low strength part which is mainly composed of at least one of a ferrite structure and a bainite structure; and a high strength part which is composed of a martensite structure. A nitrogen content of the low strength part is 50 ppm or less, and a nitrogen content of the high strength part is 70 ppm or more. Further, hardness of the low strength part is 350 Hv or less in Vickers hardness, and hardness of the high strength part is 420 Hv or more in Vickers hardness. |
