Materials Factors Influencing the Initiation of Near-Neutral pH SCC on Underground Pipelines

2000 ◽  
Author(s):  
John A. Beavers ◽  
Joshua T. Johnson ◽  
Robert L. Sutherby
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Chemical Composition ◽  
Cyclic Stress ◽  
Strain Behavior ◽  
Inclusion Properties ◽  
Neutral Ph ◽  
Underground Pipelines ◽  
Factors Influencing ◽  
Stress Surface

This paper summarizes the results of research, funded by the Canadian Energy Pipeline Association (CEPA), to determine whether the initiation of near-neutral pH stress corrosion cracking (SCC) could be correlated with pipe metallurgical factors. The factors considered included residual stress, surface roughness, chemical composition, cyclic stress-strain behavior, inclusion properties (number, area, and composition), microhardness, and local galvanic behavior. The project focused on pipes installed from the 1950s through 1970s that exhibit near-neutral-pH SCC. Fourteen pipe samples were examined, ranging in diameter from 8 to 42 inches and grades from X52 to X70.

scholarly journals Effect of Lubrication and Forging Load on Surface Roughness, Residual Stress, and Deformation of Cold Forging Tools

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 783
Author(s):  
Karunathilaka ◽  
Tada ◽  
Uemori ◽  
Hanamitsu ◽  
Fujii ◽  
...  
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
High Speed ◽  
Compressive Force ◽  
Cold Forging ◽  
Metallic Contact ◽  
Heat Treated ◽  
Stress Surface ◽  
Stress And Deformation ◽  
Forging Load

Cold forging is a metal forming that which uses localized compressive force at room temperature. During the cold forging process, the tool is subjected to extremely high loads and abrasive wear. Lubrication plays an important role in cold forging to improve product quality and tool life by preventing direct metallic contact. Surface roughness and residual stress also greatly affects the service life of a tool. In this study, variations in surface roughness, residual stress, and specimen deformation with the number of cold forging cycles were investigated under different forging conditions. Specimens that were made of heat-treated SKH51 (59–61 HRC), a high-speed tool steel with a polished working surface, were used. The specimens were subjected to an upsetting process. Compressive residual stress, surface roughness, and specimen deformation showed a positive relationship with the number of forging cycles up to a certain limit and became almost constant in most of the forging conditions. A larger change in residual stress and surface roughness was observed at the center of the specimens in all the forging conditions. The effect of the magnitude of the forging load on the above discussed parameters is large when compared to the effect of the lubrication conditions.

Effects of different shot peening parameters on residual stress, surface roughness and cell size

2020 ◽  
Vol 398 ◽  
pp. 126054 ◽  
Author(s):  
Qinjie Lin ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Difa Chen ◽  
Shuangshuang Zhou
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Cell Size ◽  
Shot Peening ◽  
Stress Surface

Parametric Study of Machining Effect on Residual Stress and Surface Roughness of Nickel Base Super Alloy UDIMET 720

2008 ◽  
Vol 47-50 ◽  
pp. 13-16 ◽  
Author(s):  
S.V. Joshi ◽  
S. Paul Vizhian ◽  
B.R. Sridhar ◽  
K. Jayaram
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Turbine Engine ◽  
Milling Parameters ◽  
Stress Surface ◽  
Nickel Base ◽  
Engine Components ◽  
Super Alloy

Machining parameters such as speed (v), feed (f) and depth of cut (d) play an important role in determining the residual stress as well as the surface roughness of a material. The material used for the present study is a nickel based super alloy Udiment 720 which finds applications in the manufacture of gas turbine engine components. Residual stress and surface roughness measured on this material showed different magnitudes for different combinations of milling parameters but did not reveal any definite trend. Analytical relationships developed between the magnitudes of residual stress, surface roughness and milling parameters indicated that combined effects of the milling parameters influence both residual stress and surface roughness.

scholarly journals Design and Fabrication of Laser Protective Lenses Based on Multilayered Notch Filter with Low Residual Stress and Low Surface Roughness

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1513
Author(s):  
Chuen-Lin Tien ◽  
Hong-Yi Lin ◽  
Kuan-Sheng Cheng ◽  
Chih-Kai Chang
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Filter Design ◽  
Notch Filter ◽  
Transmission Band ◽  
Optical Transmittance ◽  
Electron Beam Evaporation ◽  
Center Wavelength ◽  
Stress Surface ◽  
Probe Microscope

We present a new laser protective lens based on a multilayered notch filter design with low residual stress and low surface roughness. An18-layer notch filter was prepared by electron beam evaporation with an ion-assisted deposition technique, which was composed of SiO2 and Nb2O5 with a center wavelength of 532 nm. The optical transmittance, residual stress, surface roughness, and surface morphology were measured by a UV/VIS/NIR spectrophotometer, Twyman–Green interferometer, scanning probe microscope, Linnik microscopic interferometer, and field-emission scanning electron microscopy (FE-SEM). The transmittance of the notch filters at center wavelength is 0.2%, and the average transmittance of the transmission band is about 70%. The residual stress of the notch filter is −0.298 GPa, and the root mean square surface roughness is 1.88 nm. The experimental results show that the optical transmittance meets the design requirements.

scholarly journals Measuring the Casimir Forces with an Adhered Cantilever: Analysis of Roughness and Background Effects

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 64
Author(s):  
Ivan A. Soldatenkov ◽  
Anastasiya A. Yakovenko ◽  
Vitaly B. Svetovoy
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Short Distance ◽  
Technological Progress ◽  
Experimental Information ◽  
Casimir Forces ◽  
Raw Data ◽  
Micromechanical Devices ◽  
Negligible Contribution

Technological progress has made possible precise measurements of the Casimir forces at distances less than 100 nm. It has enabled stronger constraints on the non-Newtonian forces at short separations and improved control of micromechanical devices. Experimental information on the forces below 30 nm is sparse and not precise due to pull-in instability and surface roughness. Recently, a method of adhered cantilever was proposed to measure the forces at small distances, which does not suffer from the pull-in instability. Deviation of the cantilever from a classic shape carries information on the forces acting nearby the adhered end. We calculate the force between a flat cantilever and rough Au plate and demonstrate that the effect of roughness dominates when the bodies approach the contact. Short-distance repulsion operating at the contact is included in the analysis. Deviations from the classic shape due to residual stress, inhomogeneous thickness of the cantilever, and finite compliance of the substrate are analysed. It is found that a realistic residual stress gives a negligible contribution to the shape, while the finite compliance and inhomogeneous thickness give measurable contributions that have to be subtracted from the raw data.

scholarly journals Influences of Residual Stress, Surface Roughness and Peak-Load on Micro-Cracking: Sensitivity Analysis

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 320
Author(s):  
Jairan Nafar Dastgerdi ◽  
Fariborz Sheibanian ◽  
Heikki Remes ◽  
Hossein Hosseini Toudeshky
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Crack Formation ◽  
Peak Load ◽  
Crack Size ◽  
Effective Parameters ◽  
Load Range ◽  
Load Effect ◽  
Damage Initiation ◽  
Load Conditions

This paper provides further understanding of the peak load effect on micro-crack formation and residual stress relaxation. Comprehensive numerical simulations using the finite element method are applied to simultaneously take into account the effect of the surface roughness and residual stresses on the crack formation in sandblasted S690 high-strength steel surface under peak load conditions. A ductile fracture criterion is introduced for the prediction of damage initiation and evolution. This study specifically investigates the influences of compressive peak load, effective parameters on fracture locus, surface roughness, and residual stress on damage mechanism and formed crack size. The results indicate that under peak load conditions, surface roughness has a far more important influence on micro-crack formation than residual stress. Moreover, it is shown that the effect of peak load range on damage formation and crack size is significantly higher than the influence of residual stress. It is found that the crack size develops exponentially with increasing peak load magnitudes.

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.

Sign in / Sign up

Export Citation Format

Share Document