筒形工件环焊缝,采用中心内照法周向辐射透照,当然是最理想的方法。但当工件直径较大且厚度也较大时,用3005周向 X 射线机中心内照法透照,底片黑度达不到要求。采用内照偏心法周向辐射透照,能克服上述困难,而且透照工作效率比采用环缝...筒形工件环焊缝,采用中心内照法周向辐射透照,当然是最理想的方法。但当工件直径较大且厚度也较大时,用3005周向 X 射线机中心内照法透照,底片黑度达不到要求。采用内照偏心法周向辐射透照,能克服上述困难,而且透照工作效率比采用环缝外照法要高很多。本文介绍按比例作图,然后分析测量θ、η、α与L1、L3的关系（附图）确定一次透照长度 L3的方法。展开更多
A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ~C and initial stress level of 250 MPa. Based on the experimental stress relaxation curve, the relationship between creep strain ...A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ~C 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.展开更多
文摘筒形工件环焊缝,采用中心内照法周向辐射透照,当然是最理想的方法。但当工件直径较大且厚度也较大时,用3005周向 X 射线机中心内照法透照,底片黑度达不到要求。采用内照偏心法周向辐射透照,能克服上述困难,而且透照工作效率比采用环缝外照法要高很多。本文介绍按比例作图,然后分析测量θ、η、α与L1、L3的关系（附图）确定一次透照长度 L3的方法。
基金Project(2009CB724307)supported by the Major State Basic Research Development Program(973 Program)of China
文摘A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ~C 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.
