Application and analysis of spread die and flat container in the extrusion of a large-size, hollow, and flat-wide aluminum alloy profile

Abstract

The structure of the extrusion die has great influence on material flow balance and product quality for large-size aluminum alloy profiles, especially the pre-allocated structure, such as spread die and flat container. In this work, regarding the practical problems existing in practical production of a large-size, hollow, and flat-wide aluminum alloy profile used in the high-speed train, the porthole extrusion process with cylinder container and spread die is firstly simulated using HyperXtrude and verified experimentally. The spread die is then optimized by combining the design of experiments with response surface method. With the optimized spread die, the maximum velocity difference in the cross section of the profile reduces from 8.63 to 3.07 mm/s, and the corresponding SDV reduces from 1.56 to 0.69 mm/s. Finally, the different structures of containers are designed; the effects of cylinder container and flat containers with different transition form on material flow, billet skin, and die stress in numerical simulation process are comparatively analyzed; and the design rules of extrusion dies are summarized for large-size, hollow, and flat-wide aluminum alloy profiles. By comparison, the maximum velocity difference decreases from 14.41 to 3 mm/s, and the maximum stress on the extrusion dies decreases from 999 to 670 MPa, and the dead zone also greatly decreases in flat container extrusion.