Research On The Law Of Weld Movement And Forming Properties In The Drawing Process Of Laser Tailor-Welded Blanks

Tailor-Welded Blanks (TWBs) is a new composite sheet composed of two or more sheets with different thickness, material properties or surface coatings by the way of welding. It can satisfy the different service performance requirements of the different parts. Laser welding is chosen to produce TWBs, because the laser welding speed is quick, the weld is narrow and the damage to base metal is small. With the requirements of automobile driving safety, energy conservation and environmental protection are increasing in the society, more and more attention has been focused on the technology of TWBs. But the base metal of TWBs is different in mechanical properties and thickness, and it has weld, so the TWBs is more easily to wrinkle, rupture and springback, and there is also the weld movement problem compared with traditional sheet. So it is very important to research the stamping properties of TWBs.According to the typical square box of laser TWBs, this article has done some numerical simulation research by using of the finite element analysis software DYNAFORM. At the time of laser TWBs sheet modeling, select rigid connection to model weld, neglect the weld type and the property of heat affected zone (HAZ), it can not only simulate the practical stamping process of laser TWBs parts accurately by this way, but the treatment is also relatively simple. Study found that the weld movement laws of square box are as follows: the weld of the box bottom integrally offsets to the thick sheet, the weld of sidewall and flange gradually offsets to the thin sheet, the closer to the outer edge the greater offset of the weld. Increasing the proportion of thick sheet of the TWBs, using split blank holder, imposing constraint on the weld and setting draw beads can restrain the movement of weld effectively. Do some researches on the stamping properties of the laser TWBs center pillar of a car, analyze the usual steps and some attentions of establishing the stamping die surface, and have predicted the defects which easily come out of the stamping process. Describe the methods and principles of setting draw beads in detail, and through setting the suitable draw beads, the stamping result of the part has improved. At last, verify the accuracy of the numerical simulation result by the way of producing the actual part in factory.