中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 9 September 2015 |
（1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. China National Heavy Machinery Research Institute Corporation, Xi’an 710032, China）
Abstract:A thermal-mechanical and micro-macro coupled finite element (FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform. Then, the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed. The results show that with the increase of initial billet temperature, extrusion speed and friction coefficient, the grain uniformity is firstly improved and then deteriorated. Larger extrusion ratio leads to more uniform grain distribution. With the increase of initial billet temperature, the average grain size of the pipe first decreases and then increases. Additionally, larger extrusion ratio can bring smaller average grain size. The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.
Key words: Inconel 625 alloy; large-scale thick-walled pipe; extrusion; dynamic recrystallization; grain size; grain uniformity
