Lubrication Effects during Biaxial Stretch Forming of Galvanized Steel Compared to Interstitial-Free Steel

Abstract

In this study, the effect of lubrications in biaxial forming zone was investigated and their performances in stretch forming process were compared. Two different ultra low carbon steel sheets which are extensively used in the industries, interstitial-free steel and galvanized steel, were tested. Three different lubrications were tested and changes in the right hand of the forming limit diagrams of the materials with different lubricants were determined by using out-of-plane formability test as well as limiting dome heights were obtained for each lubricant. Moreover, strain distributions of samples, which were stretched with dry and different lubricants, were evaluated experimentally and the effectiveness of lubricants is compared. As a result, it was observed that deep-drawing oil has the highest performance among all lubricants. Furthermore, galvanized steel has lower formability under all conditions when compared to interstitial-free steel.