The Influence of Residual Stresses on Dimension Stability during Thermal Mechanical Processes for High-Precision Components

2020 ◽  
Vol 982 ◽  
pp. 151-156
Author(s):  
Xun Qiao ◽  
Xu Feng Bai ◽  
Yi Zhang ◽  
Dong Rong Meng
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
High Precision ◽  
Recent Progress ◽  
Computational Techniques ◽  
Dimension Stability ◽  
Design And Manufacture ◽  
And Control ◽  
Modern Analytical ◽  
The Revolution

This paper mainly investigated the revolution of residual stresses and dimension stability in high-precision components during thermal-mechanical processes. Especially, originate of residual stress and its influences on dimension stability, from each step of the design and manufacture processes to thermal-mechanical processes, as well as their complicated interactions were elucidated in detail. Finally, the recent progress of modern analytical and computational techniques were discussed to provide possibilities to quantitative predict and control residual stresses and dimensional stabilities in high-precision components.

Determination of the Welding Residual Stresses in Welded Joints and Their Effects on SIFs for Surface Cracks: A Review of Recent Progress

2021 ◽  
Author(s):  
Bin Qiang ◽  
Xin Wang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Recent Progress ◽  
Life Assessment ◽  
Surface Cracks ◽  
Structural Components ◽  
Welded Steel ◽  
Aspect Ratios ◽  
Wide Range

Abstract In this paper, the recent progress on the determination of welding residual stresses in Q345qD steel welded structural components and their effects on stress intensity factors for semi-elliptical surface cracks has been reviewed. Two different welded structural components: butt-welded steel plate and orthotropic steel deck (OSD) are considered. First, we summarize the results from recent studies on the experimental measurements and numerical simulations of the surface and through-thickness residual stress in the welded plate and OSD; the complete longitudinal and transverse residual stress distributions are discussed. Then, the effects of the obtained welding residual stresses on the SIFs for surface cracks in the weldments are quantified. The loading conditions considered are the combinations of service loading and residual stresses on the butt-welded plate and OSD. Semi-elliptical surface cracks with a wide range of aspect ratios and relative depths are investigated. In particular, both 3D FEA and weight function method are used for the determination of SIFs for surface cracks. The effects of welding residual stresses on SIFs are illustrated thoroughly. The current results are very important for the appropriate fatigue life assessment for welded structural components.

Measurement of Residual Stresses in Thin Films by Two-Dimensional XRD

2006 ◽  
Vol 524-525 ◽  
pp. 613-618 ◽  
Author(s):  
Bob B. He
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Residual Stresses ◽  
Recent Progress ◽  
Stress Measurement ◽  
Incident Angle ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Stress Analysis

This paper introduces the recent progress in two-dimensional X-ray diffraction as well as its applications in residual stress analysis in thin films. The stress measurement with twodimensional x-ray diffraction can be done with low incident angle and is not limited to the peaks with high two-theta angles like the conventional method. When residual stresses of thin films are measured, a low incident angle is preferred to maximize the diffraction signals from the thin films surfaces instead of from the substrates and matrix materials. Since one stress measurement at one fixed incident angle is possible, stress gradients in depth can be measured by series of incident angles. Some experimental examples are given to show the stress measurement at low and fixed incident angle.

Evaluation of the residual stress in stainless steel 304L hydraulically expanded joints

2020 ◽  
pp. 095440892096401
Author(s):  
Ying Hong ◽  
Xuesheng Wang ◽  
Yan Wang ◽  
Zhao Zhang ◽  
Yong Han
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
The Finite Element Method ◽  
Power Stations ◽  
Stainless Steel 304 ◽  
Initial Clearance

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.

scholarly journals Effects of Roughness on Stresses in an Oxide Scale Formed on a Superalloy Substrate

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 479
Author(s):  
Yang Zhao ◽  
Fan Sun ◽  
Peng Jiang ◽  
Yongle Sun
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Residual Stresses ◽  
Oxide Scale ◽  
Rough Surface ◽  
Alumina Scale ◽  
Growth Stress ◽  
Oxide Growth ◽  
Substrate Thickness ◽  
Roughness Effect

The effects of surface roughness on the stresses in an alumina scale formed on a Fecralloy substrate are investigated. Spherical indenters were used to create indents with different radii and depths to represent surface roughness and then the roughness effect was studied comprehensively. It was found that the residual stresses in the alumina scale formed around the rough surface are almost constant and they are dominated by the curvature rather than the depth of the roughness. Oxidation changes the surface roughness. The edge of the indent was sharpened after oxidation and the residual stress there was released presumably due to cracking. The residual stresses in the alumina scale decrease with increase in oxidation time, while the substrate thickness has little effect, given that the substrate is thicker than the alumina scale. Furthermore, the effect of roughness on the oxide growth stress is analysed. This work indicates that the surface roughness should be considered for evaluation of stresses in coatings.

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.

Measurement of Residual Stresses in Linear Friction Welded In-Service Inconel 718 Superalloy

2016 ◽  
Vol 879 ◽  
pp. 1800-1806 ◽  
Author(s):  
M. Smith ◽  
L. Bichler ◽  
D. Sediako
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Material ◽  
Peak Stress ◽  
Weld Interface ◽  
Aerospace Alloys ◽  
Aero Engine ◽  
Linear Friction ◽  
Inconel 718 Superalloy ◽  
Residual Strains

Measurement of residual strains by neutron diffraction of linear friction welded Inconel® 718 (IN 718) superalloy acquired from a mid-service aero-engine disk was undertaken in this study. Residual strain and stress throughout the various weld regions including the heat affected zone (HAZ), thermomechanical affected zone (TMAZ) and dynamically recrystallized zone (DRX) were characterized. The residual stresses were observed to increase from the base material to the weld interface, with a peak stress at the weld interface in all orthogonal directions. The trends for residual stress across the weld are in agreement with other work published in literature for solid state welding of aerospace alloys, where high residual stresses were commonly reported at the weld interface.

scholarly journals Residual stresses in thermite welded rails: significance of additional forging

2020 ◽  
Vol 64 (7) ◽  
pp. 1195-1212
Author(s):  
B. Lennart Josefson ◽  
R. Bisschop ◽  
M. Messaadi ◽  
J. Hantusch
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welding Process ◽  
Surface Zone ◽  
Fe Model ◽  
Uneven Surface ◽  
Residual Stress Field ◽  
High Dynamic

Abstract The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. In both cases, large tensile residual stresses are found in the rail web at the weld. Additional forging may increase the risk of hot cracking due to an increase in plastic strains within the welded area.

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Instability Parameter for Machined Parts

1983 ◽  
Vol 105 (3) ◽  
pp. 133-136 ◽  
Author(s):  
A. Israeli ◽  
J. Benedek
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Single Point ◽  
Machining Parameters ◽  
Machining Processes ◽  
Etching Technique ◽  
Parametric Relationship ◽  
Machined Parts ◽  
Instability Parameter ◽  
Stress Profiles

The production of precision parts requires manufacturing processes which produce low residual stresses. This study was designed to investigate the parametric relationship between machining processes and residual stress distribution. Sets of steel specimens were single point turned at different feeds. The residual stress profiles of these specimens were monitored, using a continuous etching technique. A “Specific Instability Potential” parameter, derived from the strain energy of the residual stresses, was found to relate directly to the machining parameters. It is suggested that the Specific Instability Potential can be used as a parameter for specifying processing operations.

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