| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a joined body of high tensile strength steel sheets and a resistance welding method for the high tensile strength steel sheet, which attains the improvement of rupture strength by suppressing the development of cracks to the inside of a nugget, without lowering productivity. <P>SOLUTION: The joined body of high tensile strength steel sheet is made by joining parts to be joined containing at least high tensile strength steel sheets overlapped mutually by resistance welding. In this joined body of high tensile strength steel sheet, in a Vickers hardness distribution curve reaching a base material through a heat-affected zone 14 from a nugget 13 measured in the low test force Vickers hardness test (test force 4.903N) according to JIS Z2244, the heat-affected zone softening width w defined as the "distance required for Vickers hardness to rise until the hardness of the base material after being lowered than the hardness of the base material, in the heat-affected zone" is of a constant width or more. <P>COPYRIGHT: (C)2013,JPO&INPIT |
