Estimation of Residual Stress in Cold Rolled Iron-Disks Using Magnetic and Ultrasonic Methods and Neutron Diffraction Technique

1994 ◽  
Vol 376 ◽  
Author(s):  
V.L. Aksenov ◽  
A.M. Balagurov ◽  
G.D Bokuchava ◽  
J. Schreiber ◽  
Yu.V. Taran Frank
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Sheet Metal ◽  
Diffraction Method ◽  
Calibration Procedure ◽  
Rolled Sheet ◽  
Forming Process ◽  
Practical Applications ◽  
Ultrasonic Methods ◽  
Cold Rolled

ABSTRACTVariation of internal stress states in cold rolled sheet metal can essentially influence the result of forming processes. Therefore it is important to control the forming process by a practicable in line testing method. For this purpose magnetic and ultrasonic nondestructive methods are available. However, it is necessary to calibrate these techniques. This paper describes a first step of such a calibration procedure making use of the neutron diffraction method. On the basis of the diffraction results an assessment of the magnetic and ultrasonic methods for the estimation of residual stress in the cold rolled iron-disks was made. Reasonable measuring concepts for practical applications to forming processes with cold rolled sheet metal are discussed.

The Influence of Sheet Metal Anisotropy on Laser Forming Process

2004 ◽  
Vol 127 (3) ◽  
pp. 572-582 ◽  
Author(s):  
Peng Cheng ◽  
Y. Lawrence Yao
Keyword(s):  
Sheet Metal ◽  
Electron Backscatter Diffraction ◽  
Plastic Anisotropy ◽  
Development Theory ◽  
Laser Forming ◽  
Uniaxial Tensile ◽  
Rolled Sheet ◽  
Forming Process ◽  
Anisotropy Index ◽  
Cold Rolled

Cold-rolled sheet metal that is often used in laser forming exhibits anisotropic properties, which are mostly caused by preferred orientations of grains developed during the severe plastic deformation such as cold rolling. In the present study, the textures of cold-rolled mild steel sheets are characterized and the influence of the plastic anisotropy on laser forming process is investigated. Deformation textures are measured in terms of pole figures and orientation distribution function (ODF) plots obtained through electron backscatter diffraction (EBSD). The anisotropy index (R-value) of the material with different rolling reductions is obtained by uniaxial tensile tests. Both are compared and agree with the texture development theory. Effects of the plastic anisotropy on bending deformation during the laser forming process are investigated experimentally and numerically. Various conditions including different laser power, scanning speed, and number of scans for sheets of different rolling reductions are considered and results are discussed. The simulation results are consistent with the experimental observations.

scholarly journals Effective residual stress prediction validated with neutron diffraction method for metal large-scale additive manufacturing

2021 ◽  
Vol 205 ◽  
pp. 109751
Author(s):  
Andrzej Nycz ◽  
Yousub Lee ◽  
Mark Noakes ◽  
Deo Ankit ◽  
Christopher Masuo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Neutron Diffraction ◽  
Large Scale ◽  
Diffraction Method ◽  
Stress Prediction ◽  
Neutron Diffraction Method

Residual Stress Evaluation of Ni Based Weld Metal Using Neutron Diffraction Method

2006 ◽  
Vol 524-525 ◽  
pp. 697-702 ◽  
Author(s):  
Shinobu Okido ◽  
Hiroshi Suzuki ◽  
K. Saito
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Neutron Diffraction ◽  
Weld Metal ◽  
Diffraction Method ◽  
Fem Analysis ◽  
Butt Weld ◽  
Stress Evaluation ◽  
Neutron Diffraction Method

Residual stress generated in Type-316 austenitic stainless steel butt-weld jointed by Inconel-182 was measured using a neutron diffraction method and compared with values calculated using FEM analysis. The measured values of Type-316 austenitic stainless steel as base material agreed well with the calculated ones. The diffraction had high intensity and a sharp profile in the base metal. However, it was difficult to measure the residual stress at the weld metal due to very weak diffraction intensities. This phenomenon was caused by the texture in the weld material generated during the weld procedure. As a result, this texture induced an inaccurate evaluation of the residual stress. Procedures for residual stress evaluation to solve this textured material problem are discussed in this paper. As a method for stress evaluation, the measured strains obtained from a different diffraction plane with strong intensity were modified with the ratio of the individual elastic constant. The values of residual stress obtained using this method were almost the same as those of the standard method using Hooke’s law. Also, these residual stress values agreed roughly with those from the FEM analysis. This evaluation method is effective for measured samples with a strong texture like Ni-based weld metal.

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.

Investigation of the residual stress in UO2-Mo composites via a neutron diffraction method

2020 ◽  
Vol 46 (10) ◽  
pp. 15889-15896 ◽  
Author(s):  
Liang Cheng ◽  
Rui Gao ◽  
Biaojie Yan ◽  
Changsheng Zhang ◽  
Ruiwen Li ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Diffraction Method ◽  
Neutron Diffraction Method

Uncertainty in Residual Stress Measurements

2008 ◽  
Author(s):  
D. M. Goudar ◽  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Measurement Techniques ◽  
Diffraction Method ◽  
Hole Drilling ◽  
Invasive Technique ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Integrity Assessment ◽  
Path Lengths

Accurate characterization of residual stress in engineering components is important in structural integrity assessment. Two commonly used methods of measuring residual stress include the neutron diffraction technique and the deep-hole drilling (DHD) technique. The former is a well-known nondestructive measurement method and the latter is a semi-invasive technique which is readily available and portable. Both these measurement techniques depend on a number of physical quantities and are therefore sensitive to errors associated with the measured data. The resulting stress uncertainties can easily become significant and compromise the usefulness of the results or lead to misinterpretation of the behaviour of stress distribution. This paper describes briefly the error analysis for both techniques. Results from earlier neutron diffraction and deep hole drilling measurements are used to illustrate the errors. It is found that the average error for both techniques is about ±20MPa. In the case of the neutron diffraction method this error is acceptable for path lengths less than a few centimetres. At greater path lengths the errors become unacceptably large. In contrast the error in the DHD is independent of depth.

Effect of Grit-Blasting on Residual Stress Field

2014 ◽  
Vol 606 ◽  
pp. 91-94
Author(s):  
Ondřej Kovářík ◽  
Petr Haušild ◽  
Zdenek Pala ◽  
Pavel Sachr ◽  
Vadim Davydov
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Mild Steel ◽  
Sample Surface ◽  
Electron Back Scatter Diffraction ◽  
Residual Stress Field ◽  
Grit Blasting ◽  
Maximum Value ◽  
Cold Rolled

The effect of grit-blasting on the development of residual stress field during the surface treatment of the cold rolled mild steel was characterized by means of neutron diffraction, nanohardness measurement and electron back-scatter diffraction. The neutron diffraction revealed strong residual compressive stress with the maximum value (about-100 MPa) situated just under the sample surface of the grit-blasted sample. The deformation profiles obtained by the nanoindentation and electron back-scatter diffraction (band slope signal) revealed the strain hardening after grit blasting up to depth of approximately 100 μm.

Measurement of Residual Stress Shakedown in Pressure/Tensile Armour Wires of Flexible Pipes by Neutron Diffraction

2015 ◽  
Author(s):  
Upul S. Fernando ◽  
Michelle Davidson ◽  
Christopher Simpson ◽  
Thilo Pirling ◽  
Kun Yan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Metal Layer ◽  
Diffraction Method ◽  
Acceptance Test ◽  
Flexible Pipes ◽  
Before And After ◽  
Unbonded Flexible Pipes ◽  
Hoop Stresses

The manufacture of unbonded flexible pipes (flowlines and risers) involves wrapping steel wires to create pressure and tensile armour layers. The forming of armour wires from vendor supply conditions to a helix shape on the pipe involves significant plastic straining and the wires that are wrapped onto the pipe are not unloaded. Therefore the armour wires in flexible pipes are expected to contain significant residual stress (RS) as a result of the plastic straining and loading during manufacture and placement. This may lead to detrimental effects on the strength, durability and the service integrity of the pipe. It is postulated that the unfavorable RS introduced during pipe manufacture reduces due to stress shakedown during the factory acceptance test (FAT) where the pipe is subjected to a high internal pressure. This paper describes the first attempts to measure RS in the armour wires in unbonded flexible pipes. The key development is the use of a neutron diffraction method which allows the measurement of RS in-situ on the manufactured pipe through the whole wire sections. Pipe samples were prepared exposing the relevant metal layer and the measurements were performed on pipe samples taken before and after performing the pressurized FAT. The effect of the FAT on the shakedown of residual stress in pressure armour wires is discussed. As shown by the measurements, the elastic strains and stresses in the pressure armour wires are much larger in the hoop direction of the pipe (i.e. along the length of the wire) than radial or axial to the pipe. In pre-FAT pipe the hoop stresses are essentially tensile on the extrados and compressive on the intrados. The results have shown that the FAT reduces the hoop strains and stresses to approximately 1/3 of their as manufactured level.

Sign in / Sign up

Export Citation Format

Share Document