Springback is one of the most serious problems in high-strength steel-sheet forming to produce automotive body parts. It is, therefore, important to control and suppress springback in the use of high-strength steels. Against this background, two springback-root-cause analysis methods were developed to identify the areas of stresses at the bottom dead point, which are the most influential in springback. One method uses stresses at the bottom dead point, and the other method uses springback driving stresses, that is, the difference between stresses before and after springback. The two methods were applied to the forming of an actual part. The areas of stresses that have a major impact on springback were identified by the two methods and were almost the same. From the viewpoint of accuracy, however the method of using springback driving stresses was more accurate than that using stresses at the bottom dead point. A countermeasure based on these results was applied to the actual part, enabling the amount of springback to be reduced substantially.

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