Investigation of Hardening Law on Welding Residual Stress Analysis for Nickel Based Alloy 82 Weld Metal

2021 ◽  
Author(s):  
MITSURU EJIRI
Author(s):  
Mitsuru Ejiri ◽  
Teppei Kubota ◽  
Yukihiro Soga ◽  
Nozomi Nishihara ◽  
Nobuyoshi Yanagida ◽  
...  

Abstract There are three types of hardening laws for evaluating welding residual stress with the finite element method (FEM): kinematic hardening law, isotropic hardening law, and combined hardening law that combine these. The purpose of this paper is to investigate which hardening law is more appropriate for the evaluation of welding residual stress of alloy 82. We first performed two types of welding tests: welding both ends of a plate, and welding the periphery of a disc. We then compared the results of mock-up welding tests with the analysis results of welding residual stress with the kinematic hardening law and combined hardening law. Both the kinematic hardening law and the combined hardening law showed a welding residual stress distribution close to the results of the mock-up welding tests, but the combined hardening law tended to be closer to the mock-up results. Therefore when it is necessary to confirm the welding residual stress of alloy 82, it is considered appropriate to apply the combined hardening law.


Author(s):  
Akira Maekawa ◽  
Shigeru Takahashi ◽  
Hisashi Serizawa ◽  
Hidekazu Murakawa

An efficient and reliable method for welding residual stress analysis is reported in this paper. The analysis method to calculate the residual stress using the iterative substructure method was developed and compared with a conventional one using a commercial finite element analysis code; comparisons were made for the analysis accuracy and the computational speed of the residual stress in a welded pipe joint. The residual stress distributions obtained by the both methods agreed well with each other. Moreover, it was clarified that the developed method could calculate the residual stress in a shorter computing time and could calculate the residual stress distribution much faster with nearly the same accuracy as the conventional method when the size of the welding structure was large.


2012 ◽  
Vol 622-623 ◽  
pp. 309-314 ◽  
Author(s):  
Xiu Li Shen ◽  
Shao Jing Dong

This paper has proposed a new shape of the twin-web turbine disc. Based on a design optimization of the shape of the twin-web turbine disc by finite element numerical calculation, we analyzed welding types and carried out the simulation of the welding process and obtained the residual stress. Finally we got a 5.8% weight loss and summarized residual stress of the welding and proved the feasibility of the new shape.


Author(s):  
Nobuyoshi Yanagida ◽  
Koichi Saito

We developed a residual stress analysis method for bead welded low alloy steel JIS SQV2A (equivalent to ASTM A533B cl. 1) plates subjected to post weld heat treatment (PWHT). Two specimens were fabricated; each was a bead welded low alloy steel plate. One was in the as-welded condition (as-welded specimen) and the other was subjected to PWHT at 625°C (PWHT specimen). Strain gauges were used to measure the distributions of the residual stress in these specimens. The measurement data showed that the longitudinal stress at the center of a bead was 0 MPa and that in the heat-affected zone was 100 MPa. The transverse stress at the center of a bead was 200 MPa in the as-welded specimen. The absolute residual stress was decreased to less than 50 MPa for the PWHT specimen. We conducted finite element analyses to predict the distributions of welding residual stress in these specimens. The amount of phase transformation strain in low alloy steel was taken into account in the welding residual stress analysis, and creep strain was taken into account in the stress mitigation analysis. The results from the analyses agree well with the experimental results. These findings prove that welding residual stress can be simulated during a thermal elastic plastic (TEP) analysis by conducting a phase transformation and taking the generation of creep strain in the PWHT samples into consideration can be used to simulate that stress mitigation.


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