scholarly journals Evolution of Residual Stresses in Linear Deposition Wire-Based Cladding of Ti-6Al-4V

2017 ◽  
Vol 905 ◽  
pp. 101-106
Author(s):  
Hadi Moztarzadeh ◽  
Darren J. Hughes ◽  
Sampan Seth ◽  
Elspeth Keating ◽  
Ercihan Kiraci ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Stress Evolution ◽  
Cnc Machine ◽  
Bernoulli Beam ◽  
Coordinate Measurement ◽  
Curvature Measurements ◽  
Residual Strains ◽  
Euler Bernoulli Beam ◽  
Wire Feed

Neutron diffraction and curvature measurements were conducted to investigate the residual stresses associated with Plasma Transferred Arc Cladding (PTA) of Ti-6Al-4V on a substrate of the same material. The wire-feed PTA coupled with 3-axis CNC machine was used as an Additive Manufacturing (AM) technique to build parts. A combination of the process parameters was chosen to investigate their effects on residual stress evolution. Neutron Diffraction (ND) measurements of residual strains were performed on the SALSA instrument at the Institut Laue-Langevin (ILL), Grenoble, France. Longitudinal stresses were also inferred by using a Coordinate Measurement Machine (CMM) and Euler-Bernoulli beam theorem. Furthermore, Optical Microscopy (OM) of the cross section of the parts was used to analyse the microstructural evolution. The results show the effect of shorter and longer ‘dwell time’ between layers on the evolution of residual stresses.

Residual Stresses in Overlapping Friction Taper Stud Welds

2010 ◽  
Vol 652 ◽  
pp. 111-115 ◽  
Author(s):  
D.G. Hattingh ◽  
Axel Steuwer ◽  
M. Neil James ◽  
I.N. Wedderburn
Keyword(s):  
Solid State ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Creep Damage ◽  
Local Damage ◽  
Planar Defects ◽  
Repair Technique ◽  
Damage Repair ◽  
Stud Welding ◽  
Residual Strains

This paper presents microstructural, hardness and residual strain information for solid-state welds in creep-resistant Cr-Mo steel, made using the new local damage repair technique offered by friction taper stud welding (FTSW). The technique is suitable for making single welds to repair, for example, localised creep damage but can also be extended to deal with planar defects through the use of overlapping welds. Neutron diffraction was used to measure residual strains at a number of positions along a series of 5 overlapping FTS welds.

A Neutron Diffraction Investigation of Residual Stresses in Rail Ends after Severe Deformation of Rail Surfaces

2014 ◽  
Vol 777 ◽  
pp. 213-218 ◽  
Author(s):  
Chandrahas Rathod ◽  
David Wexler ◽  
Vladimir Luzin ◽  
Paul Boyd ◽  
Manicka Dhanasekar
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Vertical Plane ◽  
Surface Plastic Deformation ◽  
Primary Component ◽  
Rolling Contact ◽  
Surface Plastic ◽  
Stress Evolution ◽  
Test Rig ◽  
Complex Deformation

Insulated rail joints (IRJs) are a primary component of the rail track safety and signalling systems. Rails are supported by two fishplates which are fastened by bolts and nuts and, with the support of sleepers and track ballast, form an integrated assembly. IRJ failure can result from progressive defects, the propagation of which is influenced by residual stresses in the rail. Residual stresses change significantly during service due to the complex deformation and damage effects associated with wheel rolling, sliding and impact. IRJ failures can occur when metal flows over the insulated rail gap (typically 6-8 mm width), breaks the electrically isolated section of track and results in malfunction of the track signalling system. In this investigation, residual stress measurements were obtained from rail-ends which had undergone controlled amounts of surface plastic deformation using a full scale wheel-on-track simulation test rig. Results were compared with those obtained from similar investigations performed on rail ends associated with ex-service IRJs. Residual stresses were measured by neutron diffraction at the Australian Nuclear Science and Technology Organisation (ANSTO). Measurements with constant gauge volume 3x3x3 mm3 were carried in the central vertical plane on 5mm thick sliced rail samples cut by an electric discharge machine (EDM). Stress evolution at the rail ends was found to exhibit characteristics similar to those of the ex-service rails, with a compressive zone of 5mm deep that is counterbalanced by a tension zone beneath, extending to a depth of around 15mm. However, in contrast to the ex-service rails, the type of stress distribution in the test-rig deformed samples was apparently different due to the localization of load under the particular test conditions. In the latter, in contrast with clear stress evolution, there was no obvious evolution of d0. Since d0 reflects rather long-term accumulation of crystal lattice damage and microstructural changes due to service load, the loading history of the test rig samples has not reached the same level as the ex-service rails. It is concluded that the wheel-on-rail simulation rig provides the potential capability for testing the wheel-rail rolling contact conditions in rails, rail ends and insulated rail joints.

Variation of Residual Stresses in Drawn Copper Tubes

2008 ◽  
Vol 571-572 ◽  
pp. 21-26 ◽  
Author(s):  
Adele Carradò ◽  
D. Duriez ◽  
Laurent Barrallier ◽  
Sebastian Brück ◽  
Agnès Fabre ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Material Flow ◽  
Cold Drawing ◽  
Axisymmetric Deformation ◽  
Tube Length ◽  
Inhomogeneous Deformation ◽  
Drawing Process ◽  
Process Step ◽  
Residual Strains

Seamless tubes are used for many applications, e.g. in heating, transport gases and fluids, evaporators as well as medical use and as intermediate products for hydroforming and various mechanical applications, where the final dimensions normally are given by some cold drawing steps. The first process step – piercing of the billet, for example by extrusion or 3-roll-milling - typically results in ovality and eccentricity in the tube causing non-symmetric material flow during the cold drawing process, i.e. inhomogeneous deformation. Because of this non-axisymmetric deformation and of deviations over tube length caused by moving tools, this process step generates residual stresses. To understand the interconnections between the geometrical changes in the tubes and the residual stresses, the residual strains in a copper tube had been measured by neutron diffraction.

Three-dimensional welding residual stresses evaluation based on the eigenstrain methodology via X-ray measurements at the surface

2014 ◽  
Vol 03 (04) ◽  
pp. 1450023
Author(s):  
Masaru Ogawa
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain Gauges ◽  
X Ray Diffraction ◽  
Stress Evaluation ◽  
X Ray ◽  
Residual Strains ◽  
Non Destructive ◽  
Evaluation Accuracy

In order to assure structural integrity for operating welded structures, it is necessary to evaluate crack growth rate and crack propagation direction for each observed crack non-destructively. Here, three dimensional (3D) welding residual stresses must be evaluated to predict crack propagation. Today, X-ray diffraction is used and the ultrasonic method has been proposed as non-destructive method to measure residual stresses. However, it is impossible to determine residual stress distributions in the thickness direction. Although residual stresses through a depth of several tens of millimeters can be evaluated non-destructively by neutron diffraction, it cannot be used as an on-site measurement technique. This is because neutron diffraction is only available in special irradiation facilities. Author pays attention to the bead flush method based on the eigenstrain methodology. In this method, 3D welding residual stresses are calculated by an elastic Finite Element Method (FEM) analysis from eigenstrains which are evaluated by an inverse analysis from released strains by strain gauges in the removal of the reinforcement of the weld. Here, the removal of the excess metal can be regarded as non-destructive treatment because toe of weld which may become crack starters can be eliminated. The effectiveness of the method has been proven for welded plates and pipes even with relatively lower bead height. In actual measurements, stress evaluation accuracy becomes poorer because measured values of strain gauges are affected by processing strains on the machined surface. In the previous studies, the author has developed the bead flush method that is free from the influence of the affecting strains by using residual strains on surface by X-ray diffraction. However, stress evaluation accuracy is not good enough because of relatively poor measurement accuracy of X-ray diffraction. In this study, a method to improve the estimation accuracy of residual stresses in this method is formulated, and it is shown numerically that inner welding residual stresses can be estimated accurately from the residual strains measured by X-ray diffraction.

The determination of the residual strains and stresses in a tungsten inert gas welded sheet of IN718 superalloy using neutron diffraction

2000 ◽  
Vol 35 (4) ◽  
pp. 247-259 ◽  
Author(s):  
D Dye ◽  
S. M Roberts ◽  
P. J Withers ◽  
R. C Reed
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
High Strength ◽  
Inert Gas ◽  
Hole Drilling ◽  
Nickel Based Superalloy ◽  
Residual Stress State ◽  
Reitveld Refinement ◽  
In718 Superalloy ◽  
Residual Strains

The residual stress state in a tungsten inert gas (TIG) welded sheet of IN718, a high-strength nickel-based superalloy, has been characterized using neutron diffraction. The measurements were performed using a time-of-flight diffractometer, which allowed lattice strains from the γ-γ′ {111} and γ-γ′ {311} composite peaks to be compared with the Reitveld-refined spectra. Residual stresses were estimated using plane-specific values of Young's modulus and Poisson's ratio for the {311} and {111} peaks, and the macroscopic material response for the Reitveld-refined data. These values were obtained from a theoretical analysis of existing data after Kröner. The weld considered was an autogenous TIG weld 180mm long placed centrally on to a 2mm × 100mm × 200mm solution heat-treated sheet of IN718. The strain was mapped over the central 140mm of the plate; within this region, the measured strains were almost constant along the length, with the peak bulk longitudinal strain of 1700 × 10-6 detected 4mm from the weld centre, in the heat-affected zone. The corresponding peak longitudinal stress was 270 MPa, and the tensile region 11 mm wide, with the longitudinal residual stresses typically up to 2.5 times greater than those in the transverse direction. It was also found that, while in-weld stresses derived from analysis of single peaks may be incorrect due to textural and compositional effects, those derived from Reitveld refinement of the entire spectrum showed reasonable agreement with those obtained from incremental hole drilling measurements made with the Matthar-Soete method.

scholarly journals Residual Stresses in the Hot Sprues of as-cast Mg-Zn Alloys Investigated by STRESS-SPEC Neutron Diffractometer

2013 ◽  
Vol 768-769 ◽  
pp. 428-432
Author(s):  
Wei Min Gan ◽  
Yuan Ding Huang ◽  
Zhi Wang ◽  
Norbert Hort ◽  
Michael Hofmann
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Hot Tearing ◽  
Neutron Diffractometer ◽  
Zn Content ◽  
Residual Strains ◽  
Zn Alloys ◽  
Hot Tearing Susceptibility

Residual strains near the sprues of ingots with different contents of Zn (6 wt. % and 9 wt. %) were measured using neutron diffraction. The results showed that the increase of Zn content decreases the residual stress in the hot sprue region. These results are good in agreement with that obtained by the measurement of hot tearing susceptibility.

Intergranular Strains in Pre-Strained and Welded Pipes

2010 ◽  
Vol 652 ◽  
pp. 13-18 ◽  
Author(s):  
M.O. Acar ◽  
P. John Bouchard ◽  
Joao Quinta da Fonseca ◽  
Michael E. Fitzpatrick ◽  
S. Gungor
Keyword(s):  
Plastic Deformation ◽  
Neutron Diffraction ◽  
Plastic Strain ◽  
Residual Stresses ◽  
Annealing Effect ◽  
Butt Weld ◽  
Prior Plastic Deformation ◽  
Residual Strains ◽  
Lattice Planes ◽  
Intergranular Strains

Neutron diffraction has been used to investigate the weld residual stresses and the intergranular residual strains in butt-welded 316H pipes. Measurements have been made on pipes subjected to varying degrees of plastic pre-straining before welding, in order to assess the effects of plastic strain on the weld residual stresses and the intergranular strains in the material. The intergranular strains following plastic deformation will also be affected by the annealing effect of the welding. Pipes were initially prepared with plastic strain of 0, 10, 15, 20 and 25% plastic deformation. Thereafter, the pipes were cut in half and welded with a circumferential butt-weld. Bar specimens were extracted from the remote end of the 0, 10, 15, 20 and 25% pre-strained and welded pipes. Cross-weld bar specimens were also machined from the 0 and 20% pre-strained and welded pipes. Neutron diffraction measurements were made at ENGIN-X, ISIS and FRM-II, Munich. The aim of this paper is to evaluate the intergranular strains developed after pre-straining from measurements made in remote bar specimens from the remote-end of the pipes. The annealing effect of the welding cycle on the intergranular strains is also studied, with measurements done at several points on cross-weld bar specimens, obtaining the strain response of different hkl lattice planes. The results show that the {200} and {220} planes are at the extremes of response during loading. Furthermore, the welding thermal cycling relaxed the intergranular strains from the prior plastic deformation.

Non-Destructive Measurement of Residual Stresses in U-0.8 WT% Ti by Neutron Diffraction

1989 ◽  
Vol 166 ◽  
Author(s):  
A. Salinas-Rodriguez ◽  
J.H. Root ◽  
T.M. Holden ◽  
S.R. Macewen ◽  
G.M. Ludtka
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Wall Thickness ◽  
Radial Stress ◽  
Biaxial Stress ◽  
Axial Residual Stress ◽  
Residual Strains ◽  
The Difference ◽  
Hoop Stresses

ABSTRACTThe macroscopic residual stress distribution in γ-quenched and stress levelled U-0.8wt% Ti alloy tubes was studied using neutron diffraction techniques. Residual strains were evaluated from the difference in d-spacings measured in the tubes and in small reference samples machined from each tube. Residual stresses were calculated with the isotropic bulk values of the elastic constants for polycrystalline α-U. Quenching from the γ field resulted in a nearly equi-biaxial stress state at every point across the wall thickness of the tube. The magnitude of the radial stress was very small compared with that of the axial and hoop stresses which were compressive at the surfaces and tensile in the interior. Stress levelling relieved almost completely the hoop residual stress without affecting the radial stress. The axial residual stress becomes tensile through the wall thickness and remains constant at about 20% of its magnitude in the as-quenched condition.

Experimental Investigation of Displacement/Strain Fields in Metal Coatings Deposited on Ceramic Substrates by Thermal Spraying

2015 ◽  
Vol 240 ◽  
pp. 174-182 ◽  
Author(s):  
Dariusz Golański ◽  
Grzegorz Dymny ◽  
Małgorzata Kujawińska ◽  
Tomasz Chmielewski
Keyword(s):  
Residual Stresses ◽  
Thermal Spraying ◽  
Diffraction Method ◽  
High Sensitivity ◽  
X Ray Diffraction ◽  
Strain Fields ◽  
Ceramic Substrates ◽  
Curvature Measurements ◽  
Titanium Coatings ◽  
Residual Strains

The paper presents the initial results of application of the high sensitivity grating interferometry (GI) method in order to measure the displacement and strain fields in copper and titanium coatings thermally sprayed onto alumina ceramic (Al2O3). The residual stresses had been relieved by iterative cutting method, which was applied twice. The displacement maps of u and v were measured after each cut and εxx and εyy maps were calculated. The results clearly show the presence of εxx strains relieved along the second cut. The comparison of both samples confirmed that residual strains in Ti/Al2O3 are more significant than in Cu/Al2O3 system. The result after relevant postprocessing had been supplemented with the sub-surface principal residual stresses measured in the selected point by the x-ray diffraction method and curvature measurements.

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