Residual Stresses in Steel and Zirconium Weldments

1997 ◽  
Vol 119 (2) ◽  
pp. 137-141 ◽  
Author(s):  
J. H. Root ◽  
C. E. Coleman ◽  
J. W. Bowden ◽  
M. Hayashi
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Prolonged Exposure ◽  
Electron Beam Welding ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Outer Diameter ◽  
Stress Relieving

Three-dimensional scans of residual stress within intact weldments provide insight into the consequences of various welding techniques and stress-relieving procedures. The neutron diffraction method for nondestructive evaluation of residual stresses has been applied to a circumferential weld in a ferritic steel pipe of outer diameter 114 mm and thickness 8.6 mm. The maximum tensile stresses, 250 MPa in the hoop direction, are found at mid-thickness of the fusion zone. The residual stresses approach zero within 20 mm from the weld center. The residual stresses caused by welding zirconium alloy components are partially to blame for failures due to delayed hydride cracking. Neutron diffraction measurements in a GTA-welded Zr-2.5Nb plate have shown that heat treatment at 530°C for 1 h reduces the longitudinal residual strain by 60 percent. Neutron diffraction has also been used to scan the residual stresses near circumferential electron beam welds in irradiated and unirradiated Zr-2.5Nb pressure tubes. The residual stresses due to electron beam welding appear to be lower than 130 MPa, even in the as-welded state. No significant changes occur in the residual stress pattern of the electron-beam welded tube, during a prolonged exposure to thermal neutrons and the temperatures typical of an operating nuclear reactor.

Measurement and Simulation of Residual Stresses of Electron Beam Welding Joint of Pure Aluminum

2012 ◽  
Vol 184-185 ◽  
pp. 649-652
Author(s):  
Gui Fang Guo ◽  
Shi Qiong Zhou ◽  
Liang Wang ◽  
Li Hao ◽  
Ze Guo Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Pure Aluminum ◽  
Research Result ◽  
Welding Process ◽  
Hole Drilling ◽  
Longitudinal Residual Stress

The effects of electron beam welding on the residual stresses of welded joints of pure aluminum plate 99.60 are studied by through-hole-drilling and blind-hole-drilling method. Meanwhile, based on the thermal elastic-plastic theory, and making use of ANSYS finite element procedure, a three - dimensional finite element model using mobile heat source of temperature and stresses field of electron beam welding in pure aluminum is established. The welding process is simulated by means of the ANSYS software. The results show that the main residual stress is the longitudinal residual stress, the value of the longitudinal residual stress is much larger than the transverse residual stress. But the residual stress in the thickness is rather small. And in the weld center, the maximum value of residual stresses is lower than its yield strength. The simulation results about the welded residual stresses are almost identical with the experimental results by measuring. So the research result is important to science research and engineering application.

Neutron Diffraction Residual Stress Measurements in Electron Beam Welded Compact Tension Specimens

2014 ◽  
Vol 777 ◽  
pp. 99-104
Author(s):  
Priyesh Kapadia ◽  
Catrin M. Davies ◽  
Thilo Pirling ◽  
David W. Dean ◽  
Kamran M. Nikbin
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Crack Growth ◽  
Creep Crack Growth ◽  
Compact Tension ◽  
Diffraction Measurement ◽  
Machining Processes ◽  
Residual Stresses And Strains

In a study to investigate the effect of residual stress relaxation on Creep Crack Growth (CCG) a novel fracture mechanics specimen has been designed. Compact Tension, C(T), specimens are fabricated from blocks with Electron Beam (EB) welds such that residual stresses induced during welding are retained in the specimen. Finite element analyses of EB welding and machining processes have been developed to predict the stresses in such C(T) specimens which will drive crack growth in future CCG studies. The residual stresses and strains in these samples have been quantified using the neutron diffraction measurement technique at various stages of the fabrication process and have been used to validate numerical simulations of the fabrication processes.

Characterization of the three-dimensional residual stress distribution in SiC bulk crystals by neutron diffraction

CrystEngComm ◽  
2017 ◽  
Vol 19 (43) ◽  
pp. 6527-6532 ◽  
Author(s):  
Xuejian Xie ◽  
Xiaobo Hu ◽  
Xiufang Chen ◽  
Fafu Liu ◽  
Xianglong Yang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Residual Stress Distribution ◽  
Bulk Crystals ◽  
First Time ◽  
Neutron Diffraction Method

The neutron diffraction method was adopted to study the three-dimensional residual stress distribution in SiC bulk crystals for the first time.

Numerical Simulation of Residual Stresses Induced in Compact Tension Specimens Using Electron Beam Welding

2012 ◽  
Author(s):  
P. Kapadia ◽  
C. M. Davies ◽  
D. W. Dean ◽  
K. M. Nikbin
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Residual Stresses ◽  
Mechanical Model ◽  
Elevated Temperatures ◽  
Electron Beam Welding ◽  
Creep Crack Growth ◽  
Crack Tip ◽  
Compact Tension ◽  
Eb Welding

In welded components residual stresses on the order of yield magnitude can exist, allowing creep damage and cracking to occur under secondary stresses at elevated temperatures. A method of inducing residual stresses in compact tension, C(T), specimens is proposed using Electron Beam (EB) welding, which is simulated using a sequential thermal-mechanical model. The thermal model has been verified by comparison to thermocouple measurements obtained from instrumented EB welding experiments on blocks made of ex-service Type 316H stainless steel. Residual stress measurements, obtained by the neutron diffraction technique, have also been used to verify the mechanical model. It has been found that in the proposed EB welding method plasticity is localised and limited to just a few millimetres away from the notch whilst at the same time exhibiting a near yield level residual stress at the crack tip. Thus this technique may allow the effects of residual stresses on creep crack growth to be investigated by the EB welding technique without material property changes due to crack tip plasticity influencing the results.

Finite Element and Experimental Analysis of Residual Stresses in Electron Beam Welded Nickel-Based Superalloys

2021 ◽  
Author(s):  
Tom Saju ◽  
M. Velu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Stress Measurement ◽  
Welding Parameters ◽  
Element Analysis ◽  
Longitudinal Residual Stress ◽  
Nimonic 80A

In this paper, two different nickel-based superalloys, namely Inconel 718 and Nimonic 80A were joined using electron beam welding techniques with three different welding parameters. A finite element analysis (FEA) using Abaqus software was carried out to calculate the residual stresses due to welding. Both transverse and longitudinal residual stresses were determined. Also, an X-ray residual stress measurement system, μ-X360 Ver. 2.5.6.2 was used for measuring transverse residual stress along and across the weld centerline. The transverse residual stress found by FEA and that measured experimentally was nearly the same thus validating the FEA. Also, the peak values of longitudinal residual stress found using the FEA were close to the yield strengths of the base metals as found elsewhere.

Residual Stress Analysis in a Thick Dissimilar Metal Weld Based on Neutron Diffraction

2004 ◽  
Author(s):  
Carsten Ohms ◽  
Dimitrios E. Katsareas ◽  
Robert C. Wimpory ◽  
Peter Hornak ◽  
Anastasius G. Youtsos
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Stress Analysis ◽  
Test Procedure ◽  
Diffraction Method ◽  
Research Centre ◽  
Dissimilar Metal ◽  
Dissimilar Metal Weld ◽  
Metal Weld

Residual stresses in welded structural components can significantly compromise their performance and lifetime. Non-destructive measurement of such stresses remains a challenging task and neutron diffraction, in principle similar to X-ray diffraction, is used in this study. At the High Flux Reactor (HFR) of the Joint Research Centre (JRC), Petten, the Netherlands, a facility is available to investigate residual stresses in components of up to 1000 kg — the Large Component Neutron Diffraction Facility (LCNDF). Residual stress measurements in a dissimilar metal weld are presented. The specimen investigated is a full-scale mock-up of a pressure vessel to primary piping bi-metallic weld. The specimen wall thickness is 51 mm. A key issue in applying neutron diffraction to welds is the reliable estimation of the stress-free lattice spacing in the heat affected zones and weld pool. The description of the test procedure and the resulting strain/stress data are presented in this paper. Based on this a predictive FEM model has been calibrated. Comparison of test data and numerical results clearly shows that the neutron diffraction method as applied at the HFR, although touching its limits in this study, is still capable of yielding 3-D stress analysis data in steel specimens of more than 50 mm thickness.

Neutron diffraction measurements of residual stress and plastic deformation in an aluminium alloy weld

1988 ◽  
Vol 23 (4) ◽  
pp. 201-211 ◽  
Author(s):  
D J Smith ◽  
R H Leggatt ◽  
G A Webster ◽  
H J Macgillivray ◽  
P J Webster ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Plastic Strain ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Accurate Indication ◽  
Neutron Diffraction Technique ◽  
Neutron Diffraction Method ◽  
Alloy Weld

The neutron diffraction technique for measuring residual stresses non-destructively in an aluminium alloy weld has been examined. Calibration experiments have been performed to determine the influence of prior plastic strain and surface effects. Comparisons have also been made with strain gauge methods using the destructive block removal and layering technique for measuring the residual stresses. It has been shown that the neutron diffraction method gives an accurate indication of the three dimensional stress distribution present in a weld and that it can also be employed to estimate the amount of prior plastic strain encountered.

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