Exploration of the material transfer effect in local loading forming of ultra-large-size integrated component with multi-rib

Isothermal local loading forming is a less-loading and flexible forging technology, which is promising to form the ultra-large-size integrated component with multi-rib by adopting small tonnage equipment. Due to the local loading characteristic, the material in the loading region can transfer into the unloading region in the transitional region. Identifying the affect region of the material transfer is important to control the material flow and obtain high-quality components under local loading way. In this work, the phenomena of the material transfer are explored and the boundaries of the transitional region are clarified. Firstly, the material transfer after each loading step is analyzed by displacement field and strain field based on finite element simulation of the ultra-large component. Meanwhile, the velocity vectors during each loading step are observed. Secondly, the variations of the material volume in different loading zones during each loading step are revealed. Subsequently, the change of material volume located far from the die partition line is analyzed. Furthermore, the induced forming problems by the material transfer effect, i.e., folding and additional strain, are elaborated. Finally, the boundaries between the transitional region and first/second loading zone are determined. The phenomena of the material transfer and the induced folding in the transitional region are verified using an eigenstructure with multi-rib by the FE simulation and physical simulation experiment.