镍基合金高温塑性变形行为的研究

发布时间：2018-08-09 11:22

【摘要】：本文对高酸性油气田用028镍基合金N08028(028)输油管道开发的热加工工艺进行了探索和研究。028镍基合金高温热塑性较差、易变形区间较窄,无法采用常规热穿孔工艺生产,其只能通过热挤压工艺途径来制造。本文主要通过制定028镍基油管热挤压工艺参数,并借助光学显微镜(OM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等分析方法,研究了该合金在950℃～1200℃温度范围内合金的热变形规律。本文得出以下结论：028镍基合金在950℃～1200℃温度范围内变形时,合金的应力应变曲线属于典型的动态再结晶曲线。随着应变速率的增加、变形温度的降低,峰值应力和稳态应力增加,而再结晶晶粒尺寸减小。高温、低应变速率条件下合金容易发生动态再结晶。通过处理实验数据得到028镍基合金的热变形激活能为420.9kJ/mol,本构方程和动态再结晶模型分别如下：ε=1.21669×1015[sinh(0.005912916σ)]3.56exp(-420886/RT) Xdrex=1-exp[-0.21×(ε-εc/ερ)1.33]合金的能耗峰值与动态再结晶的形核和生长过程相关：高应变速率条件下,能耗峰值与再结晶形核过程有关；高温条件下,能耗峰值与再结晶生长过程有关；低应变速率、低温条件下,能耗峰值与再结晶形核与生长过程相关。此外,在低温、高应变速率条件下,合金出现失稳区。根据加工图分析得到028镍基合金的最优热加工条件,即变形的开始条件为1200℃、10s-1,结束条件为1100、0.1 s-1。这样既能满足实际需求,又能降低能耗,提高生产效率。
[Abstract]:In this paper, the hot processing technology of N08028 (028) N08028 (028) oil pipeline used in high acid oil and gas fields has been explored and studied. The high temperature thermoplasticity of .028 nickel-base alloy is poor, and the deformation range is narrow, so it is impossible to adopt the conventional hot piercing process. It can only be made by hot extrusion process. In this paper, the hot extrusion process parameters of 028 Ni-based tubing were established, and the analysis methods such as (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used. The thermal deformation of the alloy was studied in the range of 950 鈩，

本文编号：2173919