Influence of Specimen Sampling on Internal Residual Stress Test

2010 ◽  
Vol 97-101 ◽  
pp. 4271-4276 ◽  
Author(s):  
Hai Gong ◽  
Yun Xin Wu ◽  
Kai Liao
Keyword(s):  
Residual Stresses ◽  
Surface Stress ◽  
Test Specimen ◽  
Stress Test ◽  
Cutting Plane ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Specimen ◽  
Specimen Edge ◽  
Specimen Sampling

Using Finite Element Method, the changing rules of residual stresses in the test specimen cut out from a quenched plate were analyzed, and suitable dimensions of the specimen for crack compliance method test was recommended. The results show that cutting has great influences on residual stresses in the specimen edge areas to a range of about one thickness, while it has little influences on stresses at the center part of the specimen; cutting mainly influences stresses normal to the cutting plane, while it has little effect on stresses parallel to the cutting plane; specimen with length bigger than 2.67 times the thickness and width bigger than 2 times the thickness is suitable for crack compliance method test, under these conditions peak stresses losing in crack compliance method results is less than 5% compared with surface stress X-ray diffraction results.

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

scholarly journals X-ray diffraction analysis of the structure and residual stresses of W/Cu multilayers

2006 ◽  
Vol 201 (7) ◽  
pp. 4372-4376 ◽  
Author(s):  
B. Girault ◽  
P. Villain ◽  
E. Le Bourhis ◽  
P. Goudeau ◽  
P.-O. Renault
Keyword(s):  
Residual Stresses ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
X Ray

Investigation of Residual Stress/Strain and Texture in a Large Dissimilar Metal Weld Using Synchrotron Radiation and Neutrons

2013 ◽  
Vol 772 ◽  
pp. 193-199 ◽  
Author(s):  
Carsten Ohms ◽  
Rene V. Martins
Keyword(s):  
Synchrotron Radiation ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Large Scale ◽  
High Energy ◽  
X Ray Diffraction ◽  
Butt Weld ◽  
X Ray ◽  
Component Size ◽  
Thin Slice

Bi-metallic piping welds are frequently used in light water nuclear reactors to connect ferritic steel pressure vessel nozzles to austenitic stainless steel primary cooling piping systems. An important aspect for the integrity of such welds is the presence of residual stresses. Measurement of these residual stresses presents a considerable challenge because of the component size and because of the material heterogeneity in the weld regions. The specimen investigated here was a thin slice cut from a full-scale bi-metallic piping weld mock-up. A similar mock-up had previously been investigated by neutron diffraction within a European research project called ADIMEW. However, at that time, due to the wall thickness of the pipe, stress and spatial resolution of the measurements were severely restricted. One aim of the present investigations by high energy synchrotron radiation and neutrons used on this thin slice was to determine whether such measurements would render a valid representation of the axial strains and stresses in the uncut large-scale structure. The advantage of the small specimen was, apart from the easier manipulation, the fact that measurement times facilitated a high density of measurements across large parts of the test piece in a reasonable time. Furthermore, the recording of complete diffraction patterns within the accessible diffraction angle range by synchrotron X-ray diffraction permitted mapping the texture variations. The strain and stress results obtained are presented and compared for the neutron and synchrotron X-ray diffraction measurements. A strong variation of the texture pole orientations is observed in the weld regions which could be attributed to individual weld torch passes. The effect of specimen rocking on the scatter of the diffraction data in the butt weld region is assessed during the neutron diffraction measurements.

scholarly journals The Effect of Specimen Size on Residual Stresses in Friction Stir Welded Aluminum Components

2014 ◽  
Vol 996 ◽  
pp. 445-450 ◽  
Author(s):  
Wulf Pfeiffer ◽  
Eduard Reisacher ◽  
Michael Windisch ◽  
Markus Kahnert
Keyword(s):  
Residual Stresses ◽  
Specimen Size ◽  
Hole Drilling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Friction Stir ◽  
Metal Parts ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Drilling Method

Friction stir welding (FSW) is a well-known technique which allows joining of metal parts without severe distortion. Because FSW involves less heat input relative to conventional welding, it may be assumed that cutting specimens from larger friction stir welded components results in a negligible redistribution of residual stresses. The aim of the investigations was to verify these assumptions for a welded aluminum plate and a circumferentially-welded aluminum cylinder. Strain gage measurements, X-ray diffraction and the incremental hole drilling method were used.

A Kinematic Hardening Finite Elements Model to Evaluate Residual Stresses in Shot-Peened Parts, Local Measurements by X-Ray Diffraction

2006 ◽  
Vol 524-525 ◽  
pp. 161-166 ◽  
Author(s):  
Choumad Ould ◽  
Emmanuelle Rouhaud ◽  
Manuel François ◽  
Jean Louis Chaboche
Keyword(s):  
Finite Elements ◽  
Residual Stresses ◽  
Shot Peening ◽  
Kinematic Hardening ◽  
Constitutive Law ◽  
Loading Path ◽  
Isotropic Hardening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Local Measurements

Experimental analysis can be very costly and time consuming when searching for the optimal process parameters of a new shot-peening configuration (new material, new geometry of the part…). The prediction of compressive residual stresses in shot-peened parts has been an active field of research for the past fifteen years and several finite elements models have been proposed. These models, although they give interesting qualitative results, over-estimate, most of the time, the level of the maximal compressive stresses. A better comprehension of the phenomena and of the influence of the parameters used in the model can only carry a notable improvement to the prediction of the stresses. The fact that the loading path is cyclic and is not radial led us to think that a model including kinematic hardening would be better adapted for the modelling of shot peening. In this article we present the results of a simulation of a double impact for several constitutive laws. We study the effect of the chosen constitutive law on the level of residual stresses and, in particular, we show that kinematic hardening, even identified on the same tensile curve than isotropic hardening, leads to lower stress levels as compared with isotropic hardening. Furthermore, the overall shape of the stress distribution within the depth is significantly different for the two types of hardening behaviour. Further, in order to check the modelisations, local measurements were carried on with X-ray diffraction on a large size impact and correlated with the topography of the impact.

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