Offshore seawater systems are commonly manufactured using a monolithic copper–nickel alloy (90%Cu10%Ni). However, because of the high cost of this material, they have been replaced in some Brazilian oil and gas platforms by C–Mn steel pipes clad with a Ni–Cu alloy (70%Ni30%Cu, Monel 400®). Therefore, considering the complex transition zone (TZ) in dissimilar weldments and its influence on the performance

Most of reactor vessel internals (RVIs) have been constructed by austenitic stainless steels (ASSs) to support and protect core from high temperature coolant and radiation particles. However, if they are operated in the harsh environment for a long time, ASS materials may undergo significant changes in micro-structural features, macroscopic deformation and strengths due to age-related degradation mechanisms

Based on two creep constraint parameters (R* and Ac), the constraint-dependent creep crack initiation (CCI) time equations of a Cr–Mo–V steel at 566 °C have been established over a wide range of C* region. The equations are independent on the choice of the reference specimen. Based on the two-parameter (C*-R* and C*-Ac) and the constraint-dependent CCI time equations, the CCI time for the specimens

This study examines the influence of probabilistic treatment of transverse residual stress in a structural integrity assessment. Pipe girth weld measurement data gathered from numerous studies was statistically interpreted to provide realistic through-thickness stress distributions for use in fracture assessments. The database measurements are shown to follow a normal distribution which is capable

For industrial components such as pressure vessels and piping systems, it is important to determine the shakedown domains of structures under complex variable thermo-mechanical loads to avoid low cycle fatigue due to alternating plasticity or incremental plastic collapse caused by ratcheting. In this paper, the interaction among three common types of stresses are considered based on a plane model,

Underground oil and gas pipelines are usually expected to be long-lasting. Corrosion of these steel pipelines may cause structural failures that significantly threaten life and cause environmental hazards. Therefore, developing a reliable approach to estimate soil corrosivity is important for designing a targeted anti-corrosion structure and performing risk assessment. In this study, an extension-based

In present work, flux assisted-tungsten inert gas (FA-TIG) welding of bimetallic P92 martensitic steel-304H austenitic stainless steel (ASS) is carried out using SiO2–TiO2 binary flux. Seven binary fluxes were prepared by varying the proportions of flux powders (SiO2 and TiO2) and the effect of flux composition on weld bead cross-section was studied. The experimental results indicated that binary flux

The work described the effect of the grain refinement in virgin P92 steel plate on the microstructural and mechanical behavior of the P92 welded joint. The as-received P92 steel plate was subjected to varying heat-treatment, i.e., conventional heat treatment (CNT) and double normalized heat treatment (DNT) to refine the grain structure. The DNT is mainly done for the grain refinement in the as-received

A lightweight type-4 cylinder is developed using a polyethylene terephthalate (PET) liner for application in drones. We conducted a parametric study on the internal phenomena of the developed cylinder during the filling process to examine the applicability of the cylinder to drones. First, we fabricated a type-4 cylinder with a volume of 6.8 L. Then, variations in pressure and temperature inside the

The progressive loss of integrity of production tubing results from time- and space- variant degradation processes, mainly scale and corrosion. Due to the potential disastrous consequences of failure, it is necessary and required to manage the integrity of production tubing systems by means of inspections, monitoring and maintenance. However, there are substantial uncertainties associated with the

The present study addresses outcomes of extensive nonlinear finite element analyses concerning a diverse geometric spectrum ranging from 30° to 180° pipe bend configurations accounting for the initial geometric deformations of the cross-sections resulting from the bending fabrication process. Pipe bends are modeled with the realistic and accurate cross-section by incorporating initial ovality and thinning/thickening

The use of Pipeline Inspection Gauges (PIGs) to clean the pipes and understand the exact location of existing pipes is essential to protect them from damage during operation. In-depth study of the most important component sealing disc is a new method to solve the failure of the current PIG in the working process. This study focuses on redesigning the sealing disc in combination with soft robot drive

Paper deals in-depth with the topic of sustained stress indices applicable to 90° elbows based on non-linear finite element analysis models. A comprehensive overview of the existing literature sources is given in the first part of the paper, showing that there are little sources which deal specifically with this topic and that the ones that do exist result in important scatter of the results. As a

The importance of reliability-based design and assessment has been widely recognized by the pipeline industry. Thus, this paper aims at providing comprehensive reliability assessment of intact and defected pipes subjected to internal pressure based on the CSA Z662:19. Various limit states related the pipe design, pre-commission hydrostatic testing, and operation are studied. Specifically, both corrosion

Because of the presence of second-phase particles or nanoscale particles, a term of threshold stress incorporated into the power-law creep model of some materials, such as magnesium, aluminum, and chromium alloys. The estimation of the creep crack-tip stress field for these materials is notably important to facilitate their exploitation in high-temperature structures. In the present work, a two-term

Four different saturation stress based models were employed to investigate the uniaxial tensile deformation behaviour of boron added Alloy 617M. Voce relationship described the tensile flow behaviour of the alloy to a reasonable extent at high strain levels over the temperatures range of 300 K–1023 K. On the contrary, the employed macroscopic Estrin-Mecking model could not provide an adequate description

The present work proposes a semi-analytical technique for solution of mixed boundary value problem in functionally graded circular annulus wherein shear modulus varies radially in power-law form while Poisson’s ratio is constant. The technique relies on two main steps. In the first step, corresponding to terms in periodic Fourier series applied individually as traction along the annulus surface, stress

In the composite pressure vessel composed of fiber-reinforced composites tubular and metal head, the discontinuity of the structure at the joint will lead to increase of local stress and the inconsistent of internal and external deformation, which is called edge effect. An analytical procedure is developed to predict the behavior of fiber-reinforced composite circular tubes under axial unilateral loading

Many pressure vessel and piping components have to withstand high internal pressures and are therefore thick-walled so that geometric effects such as stress stiffening need not be accounted for. However, thin-walled or moderately thick structures may be sensitive to these effects. Design Codes such as the ASME Boiler and Pressure Vessel Code usually provide little guidance on when they are to be accounted

Lined pipe has been widely used in gathering pipelines systems in highly corrosive gas fields because of its good economy and corrosion resistance. In this harsh environment, the accuracy of pipeline thermal expansion and stress analysis become extremely important. Specific practice for calculating the strength of lined composite pipe was not given in the pipeline stress analysis standards. The general

Delta ferrite can easily form in the reduced activation ferritic/martensitic (RAFM) steels after welding, leading to a change in mechanical properties. With the aim of clarifying the delta ferrite formation and its influence on the mechanical properties for the heat affected zones, the enlarged heat affected zones samples with 8–10 mm wide uniform temperature zone were prepared by the Gleeble 3800

The reinforced S-shaped bellows, which can withstand high internal pressure, is a kind of typical metal bellows in aerospace and nuclear industries. Bending deformation is a typical displacement compensation of the reinforced S-shaped bellows. The discussion on bending characteristics of bellows under internal pressure has strong background of engineering application. In the present study, theoretical

In this work, characteristics of premature creep failure in the over-tempered base metal (OT-BM) of a Grade 91 steel weldment are investigated with specially designed creep experiments and advanced microstructure characterization. In situ digital image correlation (DIC) strain measurements reveal that local creep strain as high as 100% accumulated in the OT-BM, compared with only 10% nominal strain

Most of the mechanical components are exposed to environmental attacks and different loading conditions, e.g., internal pressure, high-temperature gradient, and angular velocity. Therefore, investigating their mechanical behavior under operating conditions is necessary to gain higher efficiency and less mechanical failure. Due to the vast industrial applications of Aluminum (Al) alloys, in this paper

After the Columbia accident, aged composite overwrapped pressure vessels (COPVs) employed for space missions are being subjected to various examination and monitoring techniques to identify different failure modes. As an innovative approach, this paper explores the capability of Auto-Regressive model with eXogenous input (ARX) model analysis method to detect damages/flaws in COPVs utilizing the pressure

This paper is concerned with the creep-damage modelling of a Grade 91 pressurised header, which was observed to undergo in-service cracking in the weldments. A multi-axial creep damage model of Kachanov type, with a single state damage variable, has been implemented into finite element analysis to study the creep damage responses of weldments and the sub-zones i.e. the base metal (BM), weld metal (WM)

Probabilistic fracture mechanics (PFM) simulates the behavior of cracked structures and propagates uncertainties from input parameters to a failure probability or its uncertain estimate. In nuclear technology, this approach supports the assessment of the rupture probability of highly reliable pipes, which is an important parameter for the safety analysis of a nuclear power plant. For the appropriate

Dissimilar metal welds (DMW) of ferritic to austenitic stainless steel are broadly used in steam generators working in power generation industries. Frequent failure of DMWs from the heat-affected zone (HAZ) of the ferritic part necessitates structural integrity assessment of the DMWs in order to determine and extend the lifetime of these components. In this regard, typical DMWs of SA516–309L–304L and

The phase transformation of HP40Nb alloy at various temperatures and times was investigated and the microstructural evolution in aging process was characterised. Additionally, the mechanical tests were implemented for aged specimens. Experimental results indicate the microstructure of as-cast alloy consists of the austenite matrix with skeletal-shaped primary carbides. NbC carbide changes into G phase

Stainless steels are known for their high corrosion resistance and strength to be used for load-bearing components. While the fatigue behavior of common stainless steel grades such as 304 and 316 are thoroughly investigated, research on multiaxial fatigue of AISI 410 is lacking. In-phase and 90° out-of-phase multiaxial fatigue loading tests were performed on AISI 410 specimens under strain-controlled

Creep rupture assessment is a significant issue in the field of high-temperature structural integrity. In this paper, the creep rupture assessment of 3D pressure pipelines with volumetric defects subjected to cyclic thermo-mechanical loadings is done using a direct numerical approach within the framework of stress compensation method (SCM). For calculation of creep rupture limit, an extended shakedown

In this paper, the effects of original corrosion product and microbial film on soil corrosion of X80 steel were studied using electrochemical measurements, scanning electron microscope and X-ray photoelectron spectroscopy. The original corrosion product enhances the corrosion rate and improves the local corrosion sensitivity of the steel, while the positive effect of the microbial film is more significant

Pipelines must have good mechanical properties during their service life. To improve this lifetime, a protection against corrosion is applied on the steel cylinder by coupling a passive coating with an active cathodic protection. Otherwise, it is well known that the presence of internal stresses in organic coatings is a current phenomenon which can result in the loss of adhesion. These phenomena can

Aiming at the defects in the polyethylene (PE) gas pipeline, a defect detection algorithm based on image recognition is proposed. Firstly, the collected image is preliminarily screened to obtain the image with defects. Gamma correction algorithm is used to enhance the image, and then dual filtering is used to eliminate the interference of noise on image recognition. Then the defect edge is extracted

This paper presents the initial development of a high temperature life prediction method that accounts for the variability in the material properties of Grade 91 steel. The method accounts for material variability by fitting a variable 3-parameter Weibull distribution to experimental rupture data and accounts for the variability of creep deformation on the steady-state stresses via a Monte Carlo approach

High density polyethylene (HDPE) piping systems are used extensively in both industrial and societal infrastructure. However, their performance is sometimes impacted due to leakage through flanges, especially HDPE pipes with large diameters. Many factors affect leakage, including stress relaxation in the HDPE material and ambient temperature effects. Hence, this study investigates the effect of temperature

The effects of heat treatments on the susceptibility to environment-induced cracking (EIC) of the CF8A stainless steel (SS) in simulated water of a boiling water reactor (BWR) were investigated by slow strain-rate tensile (SSRT) tests. Different microstructures were resulted by subjecting the as-casted CF8A to stress relief treatment (1050 °C/2 h, C sample), thermal aging (385 °C/20000 h, A sample)

High chromium nickel-based fillers are used in nuclear dissimilar joints or repairs. Due to the risks of ductility dip cracking of Alloy 52 M weld surfacing, a nickel-based filler with a high niobium and molybdenum content (Alloy 52MSS) is expected to enhance the stability of grain boundary and improve the resistance to stress corrosion cracking. In this study, Alloy 52 M and Alloy 52MSS were used

Establishing an accurate model to predict burst pressure is desired, which has been developed for decades. Although various models have been developed, errors unavoidably appear in the prediction of burst pressures because of the uncertainty in both input variables and nonlinear relationship of such variables to the burst pressure. Consequently, machine learning models, which is a data-driven approach

Prestressed concrete cylinder pipes (PCCPs) have been applied for various water conveyance projects recently, especially in long distance. PCCPs not only bear internal water pressures, but also external loads. The excess of external loads may cause major accidents. However, the mechanical behavior of PCCPs under external load is different from that of PCCPs under internal pressure. In this study, a

To study the seismic response of buried pipelines with the high drop, a small-size test based on shaking table was conducted to analyze the effects of pipeline wall thickness, pipeline diameter and inclination angle on the seismic response of buried pipelines with high drop. Meanwhile, a finite element model was proposed for numerical simulation. The research results show that the peak axial strain

This paper presents an analytical study on thermal buckling of cylindrical shells with non-uniform thickness, which is common in engineering practice. Firstly, the shell thickness is assumed to be arbitrary in the axial direction. After solving the basic partial differential equations by the perturbation method, buckling temperature and modes in terms of thickness function and geometric sizes of the

Elastic stress release is mostly considered during material removal while measuring in-depth residual stresses inside a structure. It can give rise to large measurement errors in the case of high residual stress where plasticity effect is involved. This paper focuses on analysis of elastic-plastic stress release due to material removal and the induced error in measurement of residual stress. Simulation

The fatigue life prediction and associated fail-safe design of autofrettaged tubes require accurate stress modeling of each specific high-strength thick-walled cylinder during and after the autofrettage process, which depends largely on the elastoplastic behavior of the original steel tubes. However, the complex material behavior is dominated by the Bauschinger effect. Modeling swage autofrettage of

The selection of structural materials for elevated temperature applications relies on the availability of proper design codes based on adequate data pertaining to the properties at service-relevant loading conditions. Two of the most widely used high temperature design codes, viz, the ASME Boiler and Pressure Vessel Code and the RCC-MRx code are at variance with each other on the bilinear interaction

To improve mechanical properties of SA508 Gr1.A steels for application of leak-before-break (LBB) design in main steam line piping in nuclear power plants, the effect of cooling rate on microstructure formation, tensile properties, Charpy impact properties, and J-R fracture toughness of SA508 Gr.1A steels was analyzed. As cooling rate increased, coarse ferrite/pearlite microstructure changed to fine

Multiple cracks are frequently detected in structural components and should be assessed aimed to judge whether they can be treated as individual cracks or be combined to a larger crack. To study the ductile failure and crack interaction behavior, tensile tests using flat plates with two through-wall cracks were conducted, and 3D digital image correlation method (3D-DIC) was applied to acquire the displacement

Buried pipes suffer from various natural and human-related phenomena leading to the bending forces on such structures. The analytical models face obstacles such as the complications in modeling material behavior and the local stress concentration due to the appearance of defects are combined. This causes the accumulative over and under-estimation of pipe capacity due to the idealizations of full plastic

Ratcheting fatigue tests were carried out on the micro-alloyed 2.25Cr–Mo steel with variable mean stress (σm), stress amplitude (σa) and stress rate (σ˙) at room temperature. Increase in the σm and σa resulted in higher plastic strain accumulation and caused a reduction in fatigue life; however, rise in the σ˙ enhanced the fatigue life. Hysteresis loop analysis showed variation in plastic strain range

Geometrical deviations in the manufacture and assembly of mechanical products often result in non-parallel bearing surfaces in the bolted joint. To reveal the influence of the non-parallel bearing surface on the loosening of the bolted joint, the paper proposes a non-parallel bearing surface anti-loosening analysis model, revealing the anti-loosening mechanism of the non-parallel bearing surface, and

It is difficult to obtain J-integral values (J-values) for materials using various types of constitutive equations without performing numerical analyses. In this study, the reference plastic slope (RPS) method was applied to obtain J-values for engineering materials, for which the deformation property was expressed by a poly-linear stress-strain curve. The RPS method derives the J-value using bi-linear

In the present study, the Gas Tungsten Arc Weld (GTAW) joint of P91 steel was produced using the dissimilar IN617 grade filler wire. The welded joints have been subjected to different post-weld heat treatment (PWHT) to obtain the stable microstructure and mechanical properties for P91 heat-affected zone (HAZ). The PWHT was performed at 750 °C (less than Ac1) and 800 °C (close to Ac1). The welded joint