| 摘要 |
PROBLEM TO BE SOLVED: To provide a stable method for welding applicable to a mass- production site, by which an excellent cruciform tensile strength of the weld zone is obtained at a spot welding of high strength steel plates. SOLUTION: The method for spot welding of the high strength steel plates is characterized by the fact that an electrode is separated from the steel plates after an elapse of holding time after welding after energizing for welding is terminated and the holding time after welding is within the value given by the relation. 300-500t+250t2<=HT<=560-900t+500t2, where t stands for the plate thickness (mm), HT stands for the holding time after welding (ms). Further, the method for spot welding of the high strength steel plates is characterized by the fact that an energizing is continued even after the energizing for welding is terminated to adjust the temperature drop rate during the time of cooling of the spot-welded zone. The post-energizing current is within the range of >=70% and <=90% of the energizing current for welding and the post- energizing time is within the range of >=60% and <=100% of the energizing time for welding.
|
