FEM analysis of vacuum hot bulge forming of Hastelloy C-276 thin-walled cylindrical workpiece
来源期刊：中南大学学报(英文版)2014年第8期
论文作者：ZHU Zhi(朱智) ZHANG Li-wen(张立文) GU Sen-dong(顾森东)
文章页码：3019 - 3023
Key words：Hastelloy C-276; vacuum hot bulge forming; creep constitutive equation; finite element method
Abstract: A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ℃ and initial stress level of 250 MPa. Based on the experimental stress relaxation curve, the relationship between creep strain rate and stress has been derived. Then, a set of creep constitutive equations has been built and the values of constants arising in the constitutive equations have been determined by fitting the creep strain rate-stress curve. Close agreement between computed results and experimental ones is obtained for stress relaxation data. The creep constitutive equation set has been integrated with the commercial FE (finite element) solver MSC.Marc via the user defined subroutine, CRPLAW, for the vacuum hot bulge forming process modelling of Hastelloy C-276 thin-walled cylindrical workpiece. The temperature field, the radius-direction displacement field and the stress-strain field are calculated and analyzed. Furthermore, the bulging dimension and the final internal diameter of workpiece are predicted and the test results verify the reliability of the finite element method.
ZHU Zhi(朱智), ZHANG Li-wen(张立文), GU Sen-dong(顾森东)
(School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085, China)
Abstract:A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ℃ and initial stress level of 250 MPa. Based on the experimental stress relaxation curve, the relationship between creep strain rate and stress has been derived. Then, a set of creep constitutive equations has been built and the values of constants arising in the constitutive equations have been determined by fitting the creep strain rate-stress curve. Close agreement between computed results and experimental ones is obtained for stress relaxation data. The creep constitutive equation set has been integrated with the commercial FE (finite element) solver MSC.Marc via the user defined subroutine, CRPLAW, for the vacuum hot bulge forming process modelling of Hastelloy C-276 thin-walled cylindrical workpiece. The temperature field, the radius-direction displacement field and the stress-strain field are calculated and analyzed. Furthermore, the bulging dimension and the final internal diameter of workpiece are predicted and the test results verify the reliability of the finite element method.
Key words:Hastelloy C-276; vacuum hot bulge forming; creep constitutive equation; finite element method
