Stress Corrosion—The Engineer̕ s View

1959 ◽  
Vol 63 (582) ◽  
pp. 354-365
Author(s):  
P. H. Wall
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Tensile Stress ◽  
Stress Corrosion ◽  
Atmospheric Corrosion ◽  
Corrosive Environment ◽  
Light Alloy ◽  
Exact Analysis ◽  
Static Tensile ◽  
Static Tensile Stress

Of all those forms of corrosion with which the engineer must deal, such as atmospheric corrosion, galvanic and fretting, stress corrosion is perhaps the most difficult to understand, to predict and to prevent.Unlike that other troublesome characteristic of metals, namely fatigue, which also defies exact analysis, it is caused by static tensile stress acting in a corrosive environment (in many cases, the atmosphere). This may be due to internal residual stress or externally applied assembly stress and under such circumstances the possibility of stress corrosion occurring is ever present and is not necessarily removed by the cessation of the working loads.Most alloys are susceptible to some degree ranging from those which suffer in practice to those which only exhibit the phenomena under exaggerated laboratory conditions. Some examples are railway locomotive boilers, stainless steel construction, commercial spot-welded construction and, of course, aeroplane structures in light alloy.

Reducing Potential for Stress Corrosion Cracking During Design and Fabrication of Small Modular Reactors

2011 ◽  
Author(s):  
Lloyd A. Hackel ◽  
C. Brent Dane ◽  
Jon Rankin ◽  
Fritz Harris ◽  
Chanh Truong
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Laser Beam ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Compressive Residual Stress ◽  
Cost Effective ◽  
Corrosion Cracking ◽  
Laser Peening ◽  
Corrosive Environment

Reactor designs employ the best materials available such as Alloy 600 and Alloy 690 to resist stress corrosion cracking (SCC); yet the problem has continued to exist. As SCC is driven by three main contributors, susceptible material, corrosive environment and existence of tensile stress, eliminating any one can greatly improve the situation. In this paper we discuss a laser peening process for the nuclear industry that can convert areas of tensile stress to deep levels of compression. Laser peening induces deep levels of plasticity into materials resulting in compressive residual stress to depths of 0.100 inches (2.5 mm) or deeper. This enables increased fatigue strength and lifetimes and greatly enhances resistance to stress corrosion cracking. The deep plasticity closes the inter-granular boundaries and induces a deep layer of compressive stress dramatically improving the stress corrosion cracking (SCC) resistance of components subjected to tensile loading in a corrosive environment. The deeper plasticity generated by laser peening can be contrasted to a depth of only 0.010 inches (0.25 mm) typically achieved with conventional shot peening, a beneficial and widely used technology. Advances in laser technology have enabled highly reliable, high-rate, cost-effective processing that has made a major impact in aerospace; thousands of parts and large scale structures have been and are being treated. Advanced laser beam delivery to components has enabled cost-effective field applications. The peening is done without physical contact with the component. The technology has been approved by organizations such as the FAA, EASA and USAF and deployed to enhance lifetime of key structural components on the F-22 fighter. Component faducials on a structure are first visually detected by a camera and alignment laser and then the main laser beam is automatically aligned to the component. The technology has the potential to serve a broad range of fielded industrial applications including oil and gas lines, on-board ship applications, nuclear power plants, upstream exploration and recovery, and downstream oil refining. We will discuss examples of advanced fatigue and corrosion resistance in steels provided by the laser peening technology as well as the hardware now available for field use. The laser peening technology enables SCC mitigation via engineered compressive residual stress to be considered much more seriously at the design level for reactors.

scholarly journals Influence of Micro-Arc Oxidation Coatings on Stress Corrosion of AlMg6 Alloy

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 356 ◽  
Author(s):  
Lesław Kyzioł ◽  
Aleksandr Komarov
Keyword(s):  
Tensile Stress ◽  
Stress Corrosion ◽  
Glass Container ◽  
Ceramic Coatings ◽  
Porosity Level ◽  
Protective Properties ◽  
Micro Arc Oxidation ◽  
Static Tensile ◽  
Static Tensile Stress ◽  
Prolonged Stress

This paper shows results of a study on the corrosion behavior of micro-arc oxidation (MAO) coatings sampled from the AlMg6 alloy. The alloy was simultaneously subjected to a corrosive environment and static tensile stress. For comparative purposes, the tests were run for both coated samples and samples without coatings. The research was conducted at a properly prepared stand; the samples were placed in a glass container filled with 3.5% NaCl aqueous solution and stretched. Two levels of tensile stress were accepted for the samples: σ1 = 0.8R0.2 σ2 = R0.2, and the tests were run for two time intervals: t1 = 480 h and t2 = 1000 h. Prolonged stress corrosion tests (lasting up to 1000 h) showed that the samples covered with ceramic coatings demonstrated significantly higher corrosion resistance than the samples without the coatings. Protective properties of the coating could be explained by its structure. Surface pores were insignificant, and their depth was very limited. The porosity level of the main coating layer was 1%. Such a structure of coating and its phase composition provided high protective properties.

scholarly journals ‎‏FINDING PERCENTAGE OF BREAKDOWN STIMULATION OF ALUMINUM WIRES THAT OPERATES IN A CORROSIVE MEDIUM

2022 ◽  
Vol 26 (1) ◽  
pp. 87-94
Author(s):  
Mohammed Abdulateef Ahmed ◽  
Keyword(s):  
Tensile Stress ◽  
Electrical Energy ◽  
Electrical Current ◽  
Mechanical Resistance ◽  
Corrosive Environment ◽  
Aluminum Wire ◽  
Different Temperatures ◽  
Static Tensile ◽  
The Wire ◽  
Static Tensile Stress

The study of the duration of mechanical resistance to static tensile stress (withstand time) for an aluminum wire that being suffers from the corrosion effect stimulated by stray currents at different temperatures. Test device was designed and produced locally "in advance" in accordance with the specification (ASTM G103 - 97) to create static tensile stress of (1 N) on an aluminum wire of type ASTM (B231/B231M) with particular dimensions and utilized in the transmission of electrical energy, and when the wire is surrounded by a corrosive environment (NaCl solution) (3.5 % NaCl) at three different temperatures (25, 50, and 75 ° C) without any external electrical current causing corrosion; this symbolizes stray currents. Then compare the findings of that example to the results of the same wire's withstand time in the presence of an external electrical current generated by corrosion of type (D.C) by (5V & 3A). Following that, the resulting diagrams were analyzed, and it was discovered that the wire resistivity time (without the existence of stray currents and at a temperature of 25 ° C) completed (17 days), which is the longest duration of endure, and the lowest time of resistivity or resistance period (in the existence of an external electric current) is (18 hr.).Impact of (stray currents) at (75 ° C), and this is an indicator of the stray currents with corrosive environment temperatures on the resistance period (withstand duration) in the existence of static stress. The total stimulation increase is 1.9% between corrosion at 75°C and 25°C.

Effect of Ultrasonic Impact Treatment on the Stress Corrosion Cracking of 304 Stainless Steel Welded Joints

2008 ◽  
Author(s):  
Gang Ma ◽  
Xiang Ling
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Welded Joints ◽  
Corrosion Cracking ◽  
Coarse Grained ◽  
304 Stainless Steel ◽  
Ultrasonic Impact Treatment

High tensile weld residual stress is an important factor contributing to stress corrosion cracking (SCC). Ultrasonic impact treatment (UIT) can produce compressive stresses on the surface of welded joints that negate the tensile stresses to enhance the SCC resistance of welded joints. In the present work, X-ray diffraction method was used to obtain the distribution of residual stress induced by UIT. The results showed that UIT could cause a large compressive residual stress up to 325.9MPa on the surface of the material. A 3D finite element model was established to simulate the UIT process by using a finite element software ABAQUS. The residual stress distribution of the AISI 304 stainless steel induced by UIT was predicted by finite element analysis. In order to demonstrate the improvement of the SCC resistance of the welded joints, the specimens were immersed in boiling 42% magnesium chloride solution during SCC testing, and untreated specimen cracked after immersion for 23 hours. In contrast, treated specimens with different coverage were tested for 1000 hours without visible stress corrosion cracks. The microstructure observation results revealed that a hardened layer was formed on the surface and the initial coarse-grained structure in the surface was refined into ultrafine grains. The above results indicate that UIT is an effective approach for protecting weldments against SCC.

Effects of Laser Shock Processing on Corrosion Properties of 304 Stainless Steel

2010 ◽  
Vol 426-427 ◽  
pp. 109-113
Author(s):  
De Jun Kong ◽  
Hong Miao ◽  
A.P. Hu
Keyword(s):  
Aqueous Solution ◽  
Residual Stress ◽  
Stainless Steel ◽  
Stress Corrosion ◽  
Compressive Residual Stress ◽  
Hardened Layer ◽  
304 Stainless Steel ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Corrosion Properties

The surface of 304 stainless steel was processed by laser shock wave, its surface micro-structures were observed with SEM, and residual stresses on its surface were measured with X-ray diffraction (XRD) stress tester, and the production mechanism of residual stress was analyzed. The experiment of stress corrosion in 25% NaCl aqueous solution was finished, the crack sensitivity of stress corrosion in NaCl aqueous solution was researched, and the effects of LSP on stress corrosion resistance were analyzed. The results shown that the refined hardened-layer is acquired on the surface of 304 stainless steel by LSP, and compressive residual stress has greatly increased, which improve availably the performances of stress corrosion resistant. The time of appearing cracks is inverse ratio with compressive residual stress, and LSP decreases effectively its stress corrosion cracks.

Influence of Laser Parameters on Residual Stress Field of AISI 304 Stainless Steel Induced by Laser Peening: A Finite Element Analysis

2006 ◽  
Author(s):  
Xiang Ling ◽  
Weiwei Peng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Stress Field ◽  
Stress Corrosion ◽  
Compressive Stress ◽  
304 Stainless Steel ◽  
Laser Peening ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304

The present paper established a non-linear elastic-plastic finite element method to predict the residual compressive stress distribution induced by Laser Peening (LP) in the AISI 304 stainless steel. The two dimensional FEA model considered the dynamic material properties at high strain rate (106/s) and the evaluation of loading conditions. Effects of laser power density, laser spot size, laser pulse duration, multiple LP processes and one/two-sided peening on the compressive stress field in the stainless steel were evaluated for the purpose of optimizing the process. Numerical results have a good agreement with the measurement values by X-ray diffraction method and also show that the magnitude of compressive stress induced by laser peening is greater than the tensile welding residual stress. So, laser peening is an effective method for protecting weldments against stress corrosion crack. The above results provide the basis for studying the mechanism on prevention of stress corrosion cracking in weld joint of type 304 stainless steel by laser peening.

Effect of Ultrasonic Impact Treatment on the Stress Corrosion Cracking of 304 Stainless Steel Welded Joints

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Xiang Ling ◽  
Gang Ma
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Welded Joints ◽  
Corrosion Cracking ◽  
Coarse Grained ◽  
304 Stainless Steel ◽  
Ultrasonic Impact Treatment

High tensile weld residual stress is an important factor contributing to stress corrosion cracking (SCC). Ultrasonic impact treatment (UIT) can produce compressive stresses on the surface of welded joints that negate the tensile stresses to enhance the SCC resistance of welded joints. In the present work, X-ray diffraction method was used to obtain the distribution of residual stress induced by UIT. The results showed that UIT could cause a large compressive residual stress in access of 300 MPa on the surface of the material. A 3D finite element model was established to simulate the UIT process by using the finite element software ABAQUS. The residual stress distribution of the AISI 304 stainless steel induced by UIT was predicted by finite element analysis. In order to demonstrate the improvement of the SCC resistance of the welded joints, the specimens were immersed in boiling 42% magnesium chloride solution during SCC testing, and untreated specimen cracked after immersion for 23 h. In contrast, treated specimens with different impact duration were tested for 1000 h without visible stress corrosion cracks. The microstructure observation results revealed that a hardened layer was formed on the surface and the initial coarse-grained structure in the surface was refined into ultrafine grains. The above results indicate that UIT is an effective approach for protecting weldments against SCC.

Failure Probability Analysis Based on FRI Model for Stress Corrosion Cracking Growth Introducing Residual Stress Distribution by Weld

2012 ◽  
Author(s):  
Noriyoshi Maeda ◽  
Tetsuo Shoji
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stress Distribution ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Failure Probability ◽  
Corrosion Cracking ◽  
Protective Film

Failure probability of welds by stress corrosion cracking (SCC) in austenitic stainless steel piping is analyzed by a probabilistic fracture mechanics (PFM) approach based on an electro-chemical crack growth model (FRI model, where FRI stands for “Fracture and Reliability Research Institute” of Tohoku University in Japan). In this model, crack growth rate da/dt, where a is crack depth, is anticipated as the rate of chemical corrosion process defined by electro-chemical Coulomb’s law. The process is also related to the strain rate at the crack tip, taking the small scale yielding into consideration. Compared to the mechanical crack growth equation like the power law for SCC, FRI model can introduce many parameters affecting the generation and break of protective film on the crack surface such as electric current associated with corrosion, the frequency of protective film break and mechanical parameters such as the stress intensity factor K and its change with time dK/dt. Derived transcendental equation is transformed into non-dimensional form, and then solved numerically by iterative method. The extension of surface crack by SCC under residual stress field is simulated by developing the stress distribution in polynomial form following ASME section XI appendix A. This simulation scheme is introduced into PFM framework to derive the failure probability of austenitic stainless steel piping in nuclear power plants to be used in developing a risk-informed inservice inspection (RI-ISI) program.

The Simulation of Residual Stress for Stud Welding and Establishment of Strength Estimating Model

2008 ◽  
Vol 575-578 ◽  
pp. 816-820 ◽  
Author(s):  
Guang Tao Zhou ◽  
Xue Song Liu ◽  
Guo Li Liang ◽  
Pei Zhi Liu ◽  
De Jun Yan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Tensile Stress ◽  
Welded Joints ◽  
Welding Residual Stress ◽  
Yield Limit ◽  
Stud Welding ◽  
Welding Joints ◽  
Simulation Results ◽  
Steel Stud

The distribution and value of welding residual stress for 1Cr18Ni9 stainless steel stud welding joints was systemically simulated by ANSYS FE software. The mathematical estimating models of strength of the welded joints were established. Simulation results showed that the welding residual stress was tensile at the edge of the stud, while it was compressive stress at the position near axis center. The largest tensile stress did not exceed yield limit of material. The residual stress had more influence on the strength of welded joints.

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