| 摘要 |
PROBLEM TO BE SOLVED: To provide the spot welding method of a steel sheet for enhancing fatigue strength of a welded joint while ensuring good working efficiency. SOLUTION: In the welding method of enhancing the fatigue strength of a spot welded joint of a steel sheet äthickness t(mm), tensile strength TS(MPa)}, in a holding time Ht (ms) after spot welding (satisfying Ht=200t-80), after the lapse of the initial-stage pressurizing force holding time Hti (ms) (satisfying 0.35 Ht≤Hti≤0.65 Ht) with initial-stage pressurizing force Pi (kN) [Pi=2.45t äor Pi=2.45t(TS/270)<SP>0.5</SP>}], the pressurizing force is increased from the initial-stage pressurizing force Pi (kN) to a later-stage pressurizing force Pa (kN) (satisfying 1.5 Pi≤Pa≤2.5 Pi); and then, a later-stage pressurizing force holding time Hta (ms) (satisfying Hta=Ht-Hti) is made to elapse with the later-stage pressurizing force Pa (kN). COPYRIGHT: (C)2010,JPO&INPIT |
