Effects of process variables on the uniformity of Al-St and Al-Mg laminated composite cups produced by hydro-mechanical deep drawing operation

Abstract

Hydro-mechanical deep drawing (HMDD) process is comparatively a new technique in sheet metal forming. The present study focuses on the use of HMDD for bimetallic components comprising aluminum and steel sheets as well as aluminum and magnesium blanks. Carrying out both experiments and numerical simulations, the effects of process parameters such as drawing depth, the fluid pressure inside the die and the process temperature were profoundly investigated. To study the effect of the process temperature on the quality of the product, the specimens were formed at both the room temperature and 200°C. Considering the maximum thickness strain and thickness variation of the specimens as measures of product quality, various results, including those obtained from the design of experiments (DOE), illustrated significant impacts of all the considered factors on the quality of the final product. The findings also showed that for the bimetallic aluminum/steel specimen, the Al/St layer sequence offered a higher quality compared with the St/Al arrangement under the same process conditions. The amount of thickness strain and thickness variation in the Al/St arrangement, compared with the St/Al sequence, were respectively improved by 27.4% and 12.6%, for the optimal value of the maximum fluid pressure (150 bar). Moreover, the thickness variation of the Al/Mg specimen was smaller than that of Al/St bimetallic cup, regardless of the drawing depth.