An Inclusive Experimental Investigation on Influences of Different Process Parameters in Warm Incremental Forming of AZ31 Magnesium Sheets

Abstract

The incremental forming (IF) is a flexible sheet metal forming process, which is extensively used for low-quantity and/or prototype productions. Light alloys, such as magnesium alloys, are also interesting candidates for reducing the weights of different vehicles to reduce their fuel consumption. The present investigation is concerned with the warm incremental forming of AZ31 magnesium sheets. In this regard, the effects of different operational variables, namely the initial temperature, vertical pitch and tool diameter, on various outcome parameters such as actual in-process temperature, drawing depth, major and minor strains (forming limit diagrams), thickness reduction, spring-back, microstructure and hardness of the deformed sample are experimentally studied using the groove test. Among various parameters, it was found that the initial temperature and, consequently, the actual final temperature significantly affected the outputs of the IF process. Regarding this, a transition temperature of about 160 °C was obtained for AZ31 sheets, above which considerable changes were observed in the material behavior and the influences of several operational variables. Based on the experimental findings, a couple of predictive equations are also proposed in this article for estimation of the actual final temperature and the drawing depth of AZ31 samples incrementally deformed via the groove tests.