Influence of shrinkage loss on failure of an extrusion container associated with creep deformation.

Large extrusion container (EC) is the key part of an extrusion machine, and generally it depends on shrink fitting of multi-layers to boost its strength. Because of the harsh condition of high temperature and pressure, the shrinkage between every 2 layers of EC would be consumed due to creep deformation. However, shrinkage loss would generate insufficient support to each outer layer and result in axial endplay or crack of EC, which brings both safety issues and economic losses. Since the repair and replacement of EC due to its failure are significantly time-consuming as well as expensive, assessment of EC's lifetime related with shrinkage loss resulting from creep deformation is of great meaning and importance. However, research of this field is very limited. In this paper, based on the proposed damage-coupled constitutive model incorporating creep behavior, the relationship between shrinkage and creep deformation and the influence of shrinkage loss on EC's serving lifetime have been investigated. Furthermore, shrinkage loss under different contact presses and extrusion speeds has been discussed. Results can be used to guide the shrinkage design of EC's shrink-fitting in design stage and modify the manufacturing dimension of replacement layer after certain failure occurrence, thus prolong the serving lifetime of EC to the utmost. [ABSTRACT FROM AUTHOR]