scholarly journals Analysis of Residual Stress in Stress Harps of Grey Iron by Experiment and Simulation

2014 ◽  
Vol 996 ◽  
pp. 586-591 ◽  
Author(s):  
Pål Schmidt ◽  
Lin Peng Ru ◽  
Vadim Davydov ◽  
Mattias Lundberg ◽  
Maqsood Ahmad ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Casting Process ◽  
Axial Direction ◽  
Hole Drilling ◽  
Fe Simulations ◽  
Stress Relieving ◽  
Compressive Residual Stresses ◽  
Good Agreement ◽  
Grey Iron

Stress harps with bars of different size were used to study residual stresses due to different cooling rate during casting of a grey iron. Finite element (FE) simulations were performed to predict residual stresses from the casting process and the effect of a stress relieving heat treatment. Intended for validating the simulations, neutron diffraction (ND) and hole drilling methods were used to measure the residual stress distribution through the thickness and in a thin surface layer, respectively. Good agreement between the FE simulations and ND measurements is observed for the annealed harp and the normal and transverse directions of the as cast harp. Discrepancy occurs in the axial direction and especially in the side bars of the as cast harp for which the simulation shows much higher compressive residual stresses. The observed difference between the different techniques was discussed with respect to the characteristics of the different methods.

scholarly journals Effect of Residual Stress on the Mechanical Properties of FSW Joints with SUS409L

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yeong-Seok Lim ◽  
Sang-Hyuk Kim ◽  
Kwang-Jin Lee
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joints ◽  
Stress Measurement ◽  
Charpy Impact ◽  
Stir Zone ◽  
Hole Drilling ◽  
Friction Stir ◽  
Compressive Residual Stresses

This study was performed to investigate both the residual stress distribution and the effect of the residual stress formed at the welding region on the mechanical properties of the friction stir welded joints with 409L stainless steel sheets. Residual stress measurement with hole-drilling method; mechanical property evaluation including tensile test, Charpy impact test, and fatigue test; and microstructure observation were conducted. It has got no residual stresses to speak of at the center region of the stir zone because the stored stresses are released in the process of the dynamic recrystallization, while a small quantity of compressive residual stresses is formed at the surface region of the stir zone because of strong compression reaction by the tool shoulder. A considerable amount of compressive residual stresses is formed at the thermomechanical affected zone because of the synergy between the thermal expansion due to the heat conduction from the stir zone and mechanical compression by the tool. The formation of residual stresses shows a similar tendency between the advancing side and the retreating side. Both the mitigation of residual stress in the stir zone and the formation of compressive residual stress in the thermomechanical affected zone contribute to the improvement of the mechanical properties of the friction stir welded joints.

Prediction and Measurement of Residual Stresses Arising From Quenching of Stainless Steels

2004 ◽  
Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
M. R. Daymond
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Stainless Steels ◽  
Numerical Study ◽  
Hole Drilling ◽  
The Core ◽  
Residual Stress State ◽  
Surface Residual Stresses ◽  
Compressive Residual Stresses ◽  
Good Agreement

This paper presents results from an experimental and numerical study examining the creation of highly triaxial residual stresses in stainless steel. This was motivated by a need to model and understand creep in aged power plant. The residual stresses were introduced by rapid spray water quenching of heated solid stainless steel spheres and cylinders. Finite element (FE) simulations predicted high compressive residual stresses around the surface of the specimens and tensile residual stresses near the centre. Surface residual stresses were measured using the incremental centre-hole drilling (ICHD) technique. Neutron diffraction (ND) was used to measure the interior residual stresses. The measurements were in good agreement with FE predictions. The ND measurements confirmed that a highly triaxial residual stress state existed in the core of the specimens.

scholarly journals Influence of Vibration and Heat Treatment on Residual Stress of a Machined 12%Cr-Steel

2014 ◽  
Vol 996 ◽  
pp. 609-614 ◽  
Author(s):  
Lin Peng Ru ◽  
Johan Moverare ◽  
Pajazit Avdovic ◽  
Annethe Billenius ◽  
Zhe Chen
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Surface Layer ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Thin Surface Layer ◽  
Microstructural Changes ◽  
Low Level ◽  
Stress Relieving ◽  
Compressive Residual Stresses

In this paper we investigated the influence of vibratory stress relieving technique, which is widely used for stress relaxation of weld and casting components/structure, on machining residual stresses in a ring-component of 12%Cr-steel. It was shown that the employed vibratory treatment, without significantly altering the microstructure, turned the surface layer from tension into compression but retained the compressive residual stresses in the subsurface. In comparison, a stress relieving heat treatment, included as a reference in the study, removed completely the surface tensile residual stresses and reduced the subsurface compressive residual stresses to a low level. Significant microstructural changes in the form of recrystallization also occurred in a thin surface layer of the machining affected zone after the heat treatment.

Analysis of Welded Joint Under Residual Stresses

2014 ◽  
Author(s):  
H. P. Jawale ◽  
Rahul Singh
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Welded Joint ◽  
Weld Zone ◽  
Welding Process ◽  
Fatigue Behaviour ◽  
Hole Drilling ◽  
Building Structures ◽  
Residual Stress Field ◽  
Stress Relieving

Welded joint is most commonly used for building structures and machine components. Welding process involves heating followed by uneven cooling causing residual stress field. In conjunction with stresses due to external loads, in-service behaviour is affected due to residual stress in welded components. It induces defects, also alters crack initiation life, fatigue behaviour, breaking strength, corrosion resistance and increases the susceptibility of structure to failure by fracture. The residual stress is function of cooling rate and the size of weld. The role of residual stress associated with welding is therefore very important while designing mechanical parts. Conventional methods like heat treatment and shot-peening techniques becomes difficult to be applied for reduction of residual stress in general purpose applications. The work presented in this paper describes the measurement of residual stress using stress relieving method, based on hole-drilling technique. Subsequently, residual stresses are relived and measured using strain rosette near the weld zone. These strains value is converted in to stress value. Residual stress is quantified with respect to yield strength, making it possible to be considered for safe designing of weld components.

Residual Stress Measurement in an Ultrasonic Peened Specimen

2014 ◽  
Author(s):  
Xavier Ficquet ◽  
Malcolm Hedmar ◽  
Ed J. Kingston
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Measurement Techniques ◽  
Hole Drilling ◽  
Beam Specimen ◽  
Metal Fatigue ◽  
Ultrasonic Peening ◽  
Gauge Volume ◽  
Compressive Residual Stresses

Plastic deformation from peening induces a compressive residual stress on the treated surface which provides resistance to metal fatigue. Hence, peening is often used to extend the fatigue lives of welded components by reducing the effective tensile residual stress. This paper describes the influence of ultrasonic peening on the residual stress. For this study a four point plastically bent beam specimen, similar to the reeling process, was used. The specimen was made from 50D steel a material often used in offshore structural components. The residual stresses in the specimen were measured before ultrasonic peening with 5 different measurement techniques. After the ultrasonic peening treatment the residual stress was measured using the Incremental centre hole drilling and the ring core techniques. Measurements were carried within the homogeneously bent section location as well as outside. In order to see the variation of the results influenced by the gauge volume, strain gauges of three different sizes were used to provide results within 0.5mm, 1mm and 2mm depth. The measurements show that the ultrasonic peening surface treatment carried out induced high compressive residual stresses up to 2mm deep inside the specimen. Finally a compendium of residual stress profiles using different peening processes and materials is presented and discussed.

Comparison of Neutron and Synchrotron Diffraction Measurements of Residual Stress in Bead-on-Plate Weldments

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Anna M. Paradowska ◽  
John W. H. Price ◽  
Trevor R. Finlayson ◽  
Ulrich Lienert ◽  
Raafat Ibrahim
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Residual Strain ◽  
Development Process ◽  
Synchrotron Diffraction ◽  
Stress Relieving ◽  
Before And After ◽  
Strain Stress ◽  
Good Agreement

This paper explores the use of neutron and synchrotron diffractions for the evaluation of residual stresses in welded components. It has been shown that it is possible to achieve very good agreement between the two independent diffraction techniques. This study shows the significance of the weld start and end sites on the residual strain/stress distribution. Quantitative evaluation of the residual stress development process for multibead weldments has been presented. Some measurements were also taken before and after postweld stress relieving to establish the reduction and redistribution of the residual stress. The detailed measurements of residual stress around the weld achieved in this work significantly improve the knowledge and understanding of residual stress in welded components.

Reducing Residual Stress in 7050 Aluminum Alloy Die Forgings by Heat Treatment

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
J. S. Robinson ◽  
D. A. Tanner
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Boiling Water ◽  
Hole Drilling ◽  
Subsequent Aging ◽  
Stress Relieving

Aerospace aluminum alloy forgings can have the residual stresses arising from heat treatment reduced by modification to the quench cooling rates and subsequent aging treatments. A series of propeller hubs usually made from the alloy 2014 have been closed die forged from the less quench sensitive alloy 7050. These forgings have been subjected to various quenching and aging treatments in an attempt to improve the balance of mechanical properties with the residual stress magnitudes. These forgings were not amenable to stress relieving by cold compression or stretching. Warm water (60°C) and boiling water quenches are investigated in addition to quenching into molten salt (200°C) and uphill quenching from −196°C. Various dual aging treatments including retrogression and reaging have been evaluated in an attempt to optimize low residual stress magnitudes with mechanical properties. Residual stresses determined by the center hole-drilling strain-gauge method are reported in addition to electrical conductivity, stress corrosion cracking, fracture toughness, initiation fatigue, and tensile mechanical property variations. It was found that quenching into boiling water and salt at 200°C did substantially reduce the residual stress but had only a small detrimental effect on the majority of the properties measured. However, the influence of quench rate on fracture toughness was much more significant. This is attributed to both coarse grain boundary precipitation and heterogeneous precipitation of η on Al3Zr dispersoids within the grains, which promotes easier crack propagation.

Measurement of Residual Stresses in Large Industrial Components Using the Deep Hole Drilling Technique

2005 ◽  
Author(s):  
X. Ficquet ◽  
C. E. Truman ◽  
D. J. Smith ◽  
T. B. Brown ◽  
T. A. Dauda
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Excellent Agreement ◽  
Stress Component ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Drilling Technique ◽  
Compressive Residual Stresses

“ELIXIR – Extending Plant Life Through Improved Fabrication and Advanced Repair Methodology” was a European Union FP5 sponsored project. During the duration of the Elixir project, much work was directed at providing the necessary data for the validation of numerical modelling techniques applied to residual stress generation and hydrogen diffusion arising from the welding process. The project focussed around four industrial applications, namely petrochemical, boiler, offshore and submarine. This paper presents through-thickness residual stress measurements obtained by the University of Bristol on two of the large industrial components. The results were obtained using the deep hole drilling technique and compared to Finite Element predictions provided by other partners. The components considered are a large P275 steel set-in nozzle, typical of a boiler application and a large S690 steel set-on nozzle, typical of an offshore application. The boiler application consisted of a nozzle of diameter 600mm and thickness 50mm, on a pipe of diameter 1100mm and 100mm thickness. The offshore application was a nozzle of diameter 900mm and thickness 50mm, on a pipe of diameter 1050mm and 50mm thickness. Both the longitudinal and transverse stresses measured using deep hole drilling showed excellent agreement with Finite Element predictions through the thickness of the boiler sample. On the top surface, a zone of tensile residual stresses, over a distance of approximately 40mm, was revealed, which was equilibrated by a zone of compressive residual stresses over the final 50mm of thickness. Results for the offshore application demonstrated that at the front surface, both of the stress components were essentially zero, but both the longitudinal and transverse components rose rapidly to maxima of approximately 500MPa and 220MPa, respectively. Tensile residual stresses were supported over a distance of approximately 30mm. Over the final 20mm of thickness, compressive residual stresses existed, which again fell to approximately zero on the back face. There is excellent agreement between measurements and the Finite Element predictions for the transverse stress component, but less good agreement between measurements and predictions of the longitudinal stress component.

scholarly journals Additive Manufactured 316L Stainless-Steel Samples: Microstructure, Residual Stress and Corrosion Characteristics after Post-Processing

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 182
Author(s):  
Suvi Santa-aho ◽  
Mika Kiviluoma ◽  
Tuomas Jokiaho ◽  
Tejas Gundgire ◽  
Mari Honkanen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Sample Surface ◽  
Post Processing ◽  
Magnesium Chloride Solution ◽  
Manufacturing Method ◽  
Four Point Bending ◽  
Traditional Manufacturing ◽  
Processing Steps ◽  
Compressive Residual Stresses

Additive manufacturing (AM) is a relatively new manufacturing method that can produce complex geometries and optimized shapes with less process steps. In addition to distinct microstructural features, residual stresses and their formation are also inherent to AM components. AM components require several post-processing steps before they are ready for use. To change the traditional manufacturing method to AM, comprehensive characterization is needed to verify the suitability of AM components. On very demanding corrosion atmospheres, the question is does AM lower or eliminate the risk of stress corrosion cracking (SCC) compared to welded 316L components? This work concentrates on post-processing and its influence on the microstructure and surface and subsurface residual stresses. The shot peening (SP) post-processing levelled out the residual stress differences, producing compressive residual stresses of more than −400 MPa in the AM samples and the effect exceeded an over 100 µm layer below the surface. Post-processing caused grain refinement and low-angle boundary formation on the sample surface layer and silicon carbide (SiC) residue adhesion, which should be taken into account when using the components. Immersion tests with four-point-bending in the heated 80 °C magnesium chloride solution for SCC showed no difference between AM and reference samples even after a 674 h immersion.

Surface Modification Analysis after Shot Peening of AA 7075 in Different States

2013 ◽  
Vol 768-769 ◽  
pp. 519-525 ◽  
Author(s):  
Sebastjan Žagar ◽  
Janez Grum
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Shot Peening ◽  
Fatigue Testing ◽  
Stress Profile ◽  
Treatment Conditions ◽  
Stress Profiles ◽  
Compressive Residual Stresses

The paper deals with the effect of different shot peening (SP) treatment conditions on the ENAW 7075-T651 aluminium alloy. Suitable residual stress profile increases the applicability and life cycle of mechanical parts, treated by shot peening. The objective of the research was to establish the optimal parameters of the shot peening treatment of the aluminium alloy in different precipitation hardened states with regard to residual stress profiles in dynamic loading. Main deformations and main residual stresses were calculated on the basis of electrical resistance. The resulting residual stress profiles reveal that stresses throughout the thin surface layer of all shot peened specimens are of compressive nature. The differences can be observed in the depth of shot peening and the profile of compressive residual stresses. Under all treatment conditions, the obtained maximum value of compressive residual stress ranges between -200 MPa and -300 MPa at a depth between 250 μm and 300 μm. Comparison of different temperature-hardened aluminium alloys shows that changes in the Almen intensity values have greater effect than coverage in the depth and profile of compressive residual stresses. Positive stress ratio of R=0.1 was selected. Wöhler curves were determined in the areas of maximum bending loads between 30 - 65 % of material's tensile strength, measured at thinner cross-sections of individual specimens. The results of material fatigue testing differ from the level of shot peening on the surface layer.

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