scholarly journals Determination of Stress Profiles in Expanded Austenite by Combining Successive Layer Removal and GI-XRD

2014 ◽  
Vol 996 ◽  
pp. 155-161 ◽  
Author(s):  
Frederico Augusto Pires Fernandes ◽  
Thomas L. Christiansen ◽  
Marcel A.J. Somers
Keyword(s):  
Lattice Parameter ◽  
Free Lattice ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Successive Layer ◽  
Stress Profiles ◽  
Expanded Austenite ◽  
Successive Removal ◽  
Good Agreement

The present work deals with the evaluation of the residual-stress profile in expanded-austenite by successive removal steps using GI-XRD. Preliminary results indicate stresses of several GPa's from 111 and 200 diffraction lines. These stresses appear largest for the 200 reflection. The strain-free lattice parameter decayed smoothly with depth, while for the compressive stress a maximum value is observed at some depth below the surface. Additionally a good agreement was found between the nitrogen profile determined with GDOES analysis and the strain-free lattice parameter from XRD.

Residual Stresses and Differential Deformation of Electroplated Structures

1989 ◽  
Vol 33 ◽  
pp. 161-169
Author(s):  
G. Sheikh ◽  
I. C. Noyan
Keyword(s):  
Residual Stresses ◽  
Lattice Parameter ◽  
Stress Profile ◽  
X Ray ◽  
Residual Stress Profile ◽  
Cyclic Loading And Unloading ◽  
Nickel Substrates ◽  
Loading And Unloading

AbstractWe report the results of a recent study where nickel substrates electroplated with chromium were loaded in-situ on an x-ray diffractometer. This technique allows determination of lattice spacings in the vicinity of the interface for both the film and the substrate as a function of the applied load. We used such lattice parameter data, SEM observations of the surface and x-ray peak breadth data to study the partitioning of deformation between the film and the substrate. The data indicates progressive loss of adhesion between the film and the substrate with increasing deformation. We observe significant effect of electroplating residual stresses on the mechanical behavior of the system. The loss of adhesion between the film and the substrate coupled with the initial residual stress profile causes an apparent 'negative Poisson's ratio' for the film during initial stages of the loading. This effect disappears with cyclic loading and unloading.

scholarly journals On the determination of stress profiles in expanded austenite by grazing incidence X-ray diffraction and successive layer removal

2015 ◽  
Vol 94 ◽  
pp. 271-280 ◽  
Author(s):  
Frederico A.P. Fernandes ◽  
Thomas L. Christiansen ◽  
Grethe Winther ◽  
Marcel A.J. Somers
Keyword(s):  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layer Removal ◽  
Successive Layer ◽  
Stress Profiles ◽  
Expanded Austenite

The Mechanics Basis of Residual Stress Profiles in Proposed API 579 Appendix E

2006 ◽  
Author(s):  
P. Dong ◽  
Z. Cao
Keyword(s):  
Residual Stress ◽  
Heat Input ◽  
Stress Measurement ◽  
Measurement Data ◽  
Stress Profile ◽  
Continuous Change ◽  
Parametric Function ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Pipe Geometry

In this paper, the mechanics basis underlying the parametric through-thickness residual stress profiles proposed for the revised API 579 Appendix E are presented. The proposed residual stress profiles are governed to a large extent by a unified parametric function form valid for a broad spectrum of pipe and vessel welds. The functional relationship is established based on the comprehensive knowledge base developed within a recent major international joint industry project (JIP) under the auspice of Pressure Vessel Research Council (PVRC) and a large amount of residuals stress measurement data from recent literature. One of the most important features associated with the proposed revision is that residual stress profile is uniquely determined by two important sets of governing parameters: (1) parameters relevant to pipe geometry, i.e., r/t and t; (2) a parameter related to welding linear heat input Q (J/mm), referred to as the characteristic heat input Qˆ which has a dimension of J/mm3. As a result, the corresponding through-wall residual stress distribution exhibits a continuous change as a function of r/t, t, and Qˆ, instead of falling into a few discrete and unrelated profiles, as seen in the current Codes and Standards.

A New Finite Element Approach Without Chip Formation to Predict Residual Stress Profile Patterns in Metal Cutting

2009 ◽  
Author(s):  
S. Anurag ◽  
Y. B. Guo ◽  
Z. Q. Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Hard Turning ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Prediction ◽  
Element Approach ◽  
Stress Profiles

Residual stress prediction in hard turning has been recognized as one of the most important and challenging tasks. A hybrid finite element predictive model has been developed with the concept of plowed depth to predict residual stress profiles in hard turning. With the thermo-mechanical work material properties, residual stress has been predicted by simulating the dynamic turning process followed by a quasi-static stress relaxation process. The residual stress profiles were predicted for a series of plowed depths potentially encountered in machining. The predicted residual stress profiles agree with the experimental one in general. A transition of residual stress profile has been recovered at the critical plowed depth. In addition, the effects of cutting speed, friction coefficient and inelastic heat coefficient on residual stress profiles have also been studied and explained.

Detailed Analysis of Residual Stress Profile at Micro-Scale in Transmission Laser Bonded Titanium/Polyimide System

2008 ◽  
Author(s):  
Ankitkumar P. Dhorajiya ◽  
Mohammed S. Mayeed ◽  
Gregory W. Auner ◽  
Ronald J. Baird ◽  
Golam M. Newaz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Laser Beam ◽  
Stress Analysis ◽  
Detailed Analysis ◽  
Stress Profile ◽  
Fe Model ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Residual Stress Analysis

Detailed analysis of residual stress profile due to laser micro-joining of two dissimilar biocompatible materials, polyimide (PI) and titanium (Ti), is vital for the long-term application of bio-implants. In this work, a comprehensive three dimensional (3D) transient model for sequentially coupled thermo-mechanical analysis of transmission laser micro-joining of two dissimilar materials has been developed by using the finite element (FE) code ABAQUS, along with a moving Gaussian laser heat source. The laser beam (wavelength of 1100 nm and diameter of 0.2 mm), moving at an optimized velocity, passes through the transparent PI, gets absorbed by the absorbing Ti, and eventually melts the PI to form the bond. The laser bonded joint area is 6.5 mm long by 0.3 mm wide. First the transient heat transfer analysis is performed and the nodal temperature profile has been achieved, and then used as an input for the residual stress analysis. Non-uniform mixed meshes have been used and optimized to formulate the 3D FE model and ensure very refined meshing around the bond area. Heat resistance between the two materials has been modeled by using the thermal surface interaction technique, and melting and solidification issues have been approximated in the residual stress analysis by using the appropriate material properties at corresponding temperature. First the model has been used to observe a good bonding condition with the laser parameters like laser traveling speed, power, and beam diameter (burnout temperature of PI > maximum temperature of PI achieved during heating > melting temperature of PI) and a good combination has been found to be 100 mm/min, 3.14 W and 0.2 mm respectively. Using this combination of parameters in heating, the residual stress profile of the laser-micro-joint has been calculated using FE model after cooling the system down to room temperature of 27 °C and analyzed in detail by plotting the stress profiles on the Ti and PI surfaces. Typically the residual stress profiles on the PI surface show low value in the middle, increase to higher values at about 160 μm from the centerline of the laser travel symmetrically at both sides, and to the contrary, on Ti surface show higher values near the centerline of traveling laser beam. The residual stresses have slowly dropped away on both the surfaces as the distance from the bond region increased further. Maximum residual stresses on both the Ti and PI surfaces are at the end of the laser travel, and are in the orders of the yield stresses of respective materials.

Through-Thickness Welding Residual Stress Profile in Dissimilar Metal Nozzle Butt Weld

2010 ◽  
Author(s):  
Tae-Kwang Song ◽  
Ji-Soo Kim ◽  
Chang-Young Oh ◽  
Hong-Yeol Bae ◽  
Jun-Young Jeon ◽  
...  
Keyword(s):  
Residual Stress ◽  
Welding Residual Stress ◽  
Stress Profile ◽  
Pressurized Water ◽  
Butt Weld ◽  
Butt Welds ◽  
Residual Stress Profile ◽  
Dissimilar Metal ◽  
Stress Profiles ◽  
Water Reactors

This paper provides the through-thickness welding residual stress profile in dissimilar metal nozzle butt welds of pressurized water reactors. For systematic investigations of the effects of geometric variables, i.e. the thickness and the radius of the nozzle and the length of the safe end, on welding residual stresses, idealized shape of nozzle is proposed and elastic-plastic thermo-mechanical finite element analyses are conducted. Through-wall welding residual stress profiles for dissimilar metal nozzle butt welds are proposed, which take a modified form of existing welding residual stress profiles developed for austenitic pipe butt weld in R6 code.

Effect of Varying Cold-Drawing Deformation on Residual Stresses Measured by Neutron Diffraction in Steel Rods

2008 ◽  
Vol 571-572 ◽  
pp. 51-56 ◽  
Author(s):  
Jesus Ruiz-Hervias ◽  
Vladimir Luzin ◽  
Henry Prask ◽  
T. Gnaeupel-Herold ◽  
Manuel Elices Calafat
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
True Strain ◽  
Cold Drawing ◽  
Pearlitic Steel ◽  
Stress Profile ◽  
Degree Of Deformation ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Tyre Industry

Cold-drawing is employed to fabricate wires and rods, which are mainly used as structural reinforcements in construction as well as in the tyre industry. As a consequence of processing, a residual stress profile is developed. In this paper, residual stress profiles are measured by neutron diffraction in cold-drawn pearlitic steel rods subjected to different deformations (true strain from 0.3 to 1.7). The results show that the residual stress profile produced by cold-drawing is similar in all the samples, irrespective of the degree of deformation.

Methods for obtaining the strain-free lattice parameter when using diffraction to determine residual stress

2007 ◽  
Vol 40 (5) ◽  
pp. 891-904 ◽  
Author(s):  
P. J. Withers ◽  
M. Preuss ◽  
A. Steuwer ◽  
J. W. L. Pang
Keyword(s):  
Residual Stress ◽  
Lattice Spacing ◽  
Lattice Parameter ◽  
The State ◽  
The Body ◽  
Free Lattice ◽  
Stress Measurements

The determination of residual stress by diffraction depends on the correct measurement of the strain-free lattice spacing d_{hkl}^0, or alternatively the enforcement of some assumption about the state of strain or stress within the body. It often represents the largest uncertainty in residual stress measurements since there are many ways in which the strain-free lattice spacing can vary in ways that are unrelated to stress. Since reducing this uncertainty is critical to improving the reliability of stress measurements, this aspect needs to be addressed, but it is often inadequately considered by experimenters. Many different practical strategies for the determining of d_{hkl}^0 ordrefhave been developed, some well known, others less so. These are brought together here and are critically reviewed. In practice, the best method will vary depending on the particular application under consideration. Consequently, situations for which each method are appropriate are identified with reference to practical examples.

Assessment of Residual Stress Profiles for Fitness for Service Assessment of Pipe Girth Welds

2014 ◽  
Author(s):  
Pingsha Dong ◽  
Shaopin Song ◽  
Jinmiao Zhang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Solution Procedure ◽  
Stress Profile ◽  
Full Field ◽  
Residual Stress Profile ◽  
Estimation Scheme ◽  
Detailed Assessment ◽  
Stress Profiles ◽  
Girth Welds

This paper aims to provide a detailed assessment of some of the existing residual stress profiles prescribed in widely used fitness-for-service assessment codes and standards, such as BS 7910 Appendix Q, by taking advantage of some comprehensive residual studies that become available recently. After presenting a case study on which residual stress measurements are available for validating finite element based residual stress solution procedure, residual stress profiles stipulated in BS 7910 for girth welds are evaluated in the context of a series of parametric finite element results and a shell theory based full-field residual stress estimation scheme. As a result, a number of areas for improvement in residual stress profile development are identified, including some specific considerations on how to attain some of these improvements.

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