IN690高温合金热挤压工艺及组织演变规律研究

发布时间：2018-05-01 02:00

本文选题：IN690高温合金 + 管材挤压　；参考：《沈阳理工大学》2015年硕士论文

【摘要】：IN690高温合金是一种奥氏体型镍基变形高温合金,它具有高强度、良好的冶金稳定性、良好的焊接性和优良的加工特性,更重要是其具有优异的抗晶间应力腐蚀能力,已经成为核电管材方面的理想材料。本文通过实验数据和数值模拟的方法对IN690合金管材挤压过程进行了研究,为管材挤压的实际生产提供了理论依据。主要研究成果和结论如下:(1)通过等温恒应变速率压缩实验得到的真应力-应变曲线,系统研究了IN690合金的热变形行为。并基于热压缩实验结果,建立了IN690合金的本构关系模型。(2)对IN690合金挤压过程中的润滑行为进行数值模拟。研究了不同玻璃垫倾角下的挤压力变化,以及玻璃垫对挤压过程的影响。得到了玻璃垫合理的倾角和玻璃垫在挤压过程中的作用。(3)通过有限元软件对IN690高温合金管材挤压成形过程进行多场耦合数值模拟,研究了不同工艺参数下温度场、应力场以及挤压力的变化规律。得到了不同工艺参数对管材挤压过程的影响规律。(4)采用Fortran语言编制IN690合金的微观组织演变模型的子程序,并结合有限元软件Marc对IN690合金管材挤压过程进行了微观组织模拟,分析了不同工艺参数下管材挤压成形过程中晶粒尺寸、再结晶分数的演变规律。将模拟的平均晶粒尺寸与实验结果进行对比。验证了数值模拟的准确性,并获得了管材挤压过程合理的工艺参数。
[Abstract]:IN690 superalloy is a kind of austenitic nickel base deformed superalloy. It has high strength, good metallurgical stability, good weldability and good processing properties. More importantly, it has excellent resistance to intergranular stress corrosion. Nuclear pipe has become an ideal material. In this paper, the extrusion process of IN690 alloy tube is studied by means of experimental data and numerical simulation, which provides a theoretical basis for the practical production of tube extrusion. The main results and conclusions are as follows: (1) the thermal deformation behavior of IN690 alloy is systematically studied by the true stress-strain curve obtained by isothermal constant strain rate compression experiment. Based on the experimental results of hot compression, the constitutive relation model of IN690 alloy is established. (2) the lubrication behavior of IN690 alloy during extrusion is simulated numerically. The influence of glass cushion on extrusion process was studied. The reasonable dip angle of glass pad and the function of glass cushion in extrusion process are obtained. The numerical simulation of multi-field coupling of IN690 superalloy tube extrusion process is carried out by finite element software, and the temperature field under different technological parameters is studied. The variation of stress field and extrusion pressure. The influence of different process parameters on tube extrusion process was obtained. (4) the subroutine of microstructure evolution model of IN690 alloy was compiled by Fortran language, and the microstructure of IN690 alloy tube extrusion process was simulated with finite element software Marc. The evolution of grain size and recrystallization fraction in tube extrusion forming process with different technological parameters was analyzed. The simulated average grain size is compared with the experimental results. The accuracy of numerical simulation is verified and the reasonable technological parameters of tube extrusion process are obtained.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG376

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