Stainless Steel Pressure Vessel Research Articles

Fungal Methane Production Under High Hydrostatic Pressure in Deep Subseafloor Sediments

Fungi inhabiting deep subseafloor sediments have been shown to possess anaerobic methane (CH4) production capabilities under atmospheric conditions. However, their ability to produce CH4 under in situ conditions with high hydrostatic pressure (HHP) remains unclear. Here, Schizophyllum commune 20R-7-F01, isolated from ~2 km below the seafloor, was cultured in Seawater Medium (SM) in culture bottles fitted with sterile syringes for pressure equilibration. Subsequently, these culture bottles were transferred into 1 L stainless steel pressure vessels at 30 °C for 5 days to simulate in situ HHP and anaerobic environments. Our comprehensive analysis of bioactivity, biomass, and transcriptomics revealed that the S. commune not only survived but significantly enhanced CH4 production, reaching approximately 2.5 times higher levels under 35 MPa HHP compared to 0.1 MPa standard atmospheric pressure. Pathways associated with carbohydrate metabolism, methylation, hydrolase activity, cysteine and methionine metabolism, and oxidoreductase activity were notably activated under HHP. Specifically, key genes involved in fungal anaerobic CH4 synthesis, including methyltransferase mct1 and dehalogenase dh3, were upregulated 7.9- and 12.5-fold, respectively, under HHP. Enhanced CH4 production under HHP was primarily attributed to oxidative stress induced by pressure, supported by intracellular reactive oxygen species (ROS) levels and comparative treatments with cadmium chloride and hydrogen peroxide. These results may provide a strong theoretical basis and practical guidance for future studies on the contribution of fungi to global CH4 flux.

Phased Array Ultrasonic Testing of Stainless Steel Pipe Welds

Weld inspection of stainless steel pipes and pressure vessels is one of the most challenging and difficult inspections for ultrasonic testing. This is due to variations in grain structure and associated anisotropy. Anisotropy causes grain scattering and adversely affects propagation of sound waves. The effect is more telling for shear waves, which, in many cases, have almost no ability to penetrate the weld volume. Longitudinal waves are affected to a lesser degree by anisotropy and can be applied for such tests. Angle beam or refracted longitudinal waves are, therefore, the accepted method for stainless steel weld inspections.

Integral Hydro-Bulge Forming Method of Spherical Pressure Vessels Using a Triangle Patch Polyhedron

AbstractThis paper proposes an integral hydrobulge forming (IHBF) method using a triangular patch polyhedron as the closed preform shell. When triangular flat parts are welded along the edges in sequence, triangular patch polyhedra are naturally formed. From the radius of the spherical pressure vessel, a design formula was derived to calculate the side lengths of the triangular flat plate parts. The water pressure, water volume, average strain of molding, and amount of springback after molding, which are necessary for implementing the IHBF for practical use, were also formulated. To verify the forming performance of the spherical pressure vessel using IHBF method, the finite element method was carried out, and a stainless-steel spherical pressure vessel with a thickness of 1.0 mm and a diameter of approximately 500 mm was fabricated using the proposed IHBF method. As a result, the measured shape error expressed as roundness to diameter ratio was 0.52%, and the calculated average plastic strain was 0.02, which was approximately 1/19 times of the forming limit strain of the material. The amount of springback after forming by calculation was approximately 0.7 mm, indicating that the amount of water required for IHBF was 5.90% of the volume of the spherical pressure vessel, while the required water pressure was no bigger than 2.3 MPa. The process directly utilizes triangular flat plate parts, eliminating the need for molds to process closed preform shells resulting in a low average plastic strain during forming, thereby improving the quality of the formed spherical pressure vessels.

Development of Low-Magnetic-Permeability Welds of 316L Stainless Steel

Austenitic stainless steel is often used as the construction material for particle accelerator vacuum chambers. It is also a strong candidate construction material for helium vessels of superconducting radiofrequency cavities of highenergy, high-power particle accelerators. One of the major limitations of austenitic stainless steels for their application in particle accelerators is the relatively higher magnetic permeability of its welds. The present paper describes an experimental study to obtain a low-magnetic-permeability gas tungsten arc weld of 316L stainless steel while using ER 316L stainless steel filler metal through controlled addition of nitrogen in the argon shielding gas. It was demonstrated that 316L stainless steel welds, made with the addition of 1.5% nitrogen in the argon shielding gas, were associated with magnetic permeability close to that of the base metal. The welds exhibited good strength and ductility in addition to qualifying the impact test requirement of the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (BPVC) for operation at room temperature and liquid helium temperature (4 K). The technique is important for the fabrication of BPVC-compliant 316L stainless steel vacuum chambers and pressure vessels of particle accelerators, including helium vessels of superconducting radiofrequency cavities.

Novel Pressure Vessel for Pressurizing Corrosive Liquids With Applications in Accelerated Life Testing of Composite Materials

Abstract A system was designed for high-pressure accelerated life testing (ALT) of composite materials exposed to saline water solutions or other potentially corrosive media. The system was comprised primarily of a large stainless steel pressure vessel with the capability to perform extended pressure holds of up to 41.3 MPa at temperatures up to 70 °C. Using a nylon fabric-reinforced Buna-N rubber diaphragm as a media isolator and an inert ceramic coating on all wetted surfaces of the vessel, 3.5% saline water solutions were successfully held at test pressures and temperatures for extended periods with no evidence of corrosion or other degradation even after several days of exposure. Pressurization was achieved through a hydraulic pump system, which contained pressure monitoring equipment and valves and was isolated from the saline water by the diaphragm. The temperature of the entire vessel and contents was maintained by complete immersion in a heated, filtered water bath. The efficacy of using an elastomeric diaphragm to transfer large pressures between two near-incompressible fluids without mixing was shown, provided adequate reinforcement in the form of an interwoven fabric was provided to prevent tearing and extrusion from the extreme through-thickness stresses, particularly at clamping locations. Discussion on the effects of temperature, material, thickness, reinforcement, and sealing methods on the effectiveness and repeatability of the system is provided, and a demonstration of an accelerated test on a carbon–fiber composite is also presented.

FEM analysis of residual stress induced by repair welding in SUS304 stainless steel pipe butt-welded joint

Abstract Repair welding is widely used to repair defects such as fatigue crack and stress corrosion crack in metal structures for prolonging their service lives. However, the residual stress induced by repair welding potentially threatens the safety of the repaired weldments, especially stainless steel pipe structures and pressure vessels used in nuclear power plants. Based on the MSC. Marc software, a thermal elastic plastic finite element method with the consideration of full 3-D model, moving heat source and advanced material model was developed to simulate residual stress distribution induced by repair welding. In the current study, the effectiveness of the developed computational approach was verified by a two-pass thin-walled butt-welded SUS304 steel pipe mock-up at first. Then, the residual stress distributions in a medium thickness SUS304 steel pipe butt-welded joint before and after repair welding were investigated numerically. The simulation results show that the peak value of axial residual stress after repair welding was significantly increased, while the variation of the maximum value of hoop residual stress was limited. In addition, the effect of repair length on the feature of residual stress distribution was studied numerically. The numerical results indicate that the peak value of repair-induced residual stress decreases with the repair length. The main reason is that the longer the repair welding length is, the less local constraint will be. The residual stress distribution in the repair area at service temperature was also discussed in this study. The results obtained from the current study will be helpful in evaluating the structural integrity of repaired weldments.

应变强化对奥氏体不锈钢制压力容器应力腐蚀行为的影响

应变强化对奥氏体不锈钢制压力容器应力腐蚀行为的影响

A global buckling analysis of a pressure vessel associated with connections between main cylinder and flat plate ends

ABSTRACTIn order to evaluate the structural safety of the pressure vessel, it is necessary to consider the failure of the connection part, together with the cylindrical part in the middle and both ends, where the initial large deflection occurs. In this paper, local structural analysis for the pressure vessel considering the bolted part was carried out as well as global buckling analysis. That is, aluminium alloy and stainless steel pressure vessel models were designed for operating under high pressure equivalent to the water depth up to 2000 and 1000 m, respectively. Pressure vessel design procedure was performed by using empirical formulae and eigenvalue analysis by an FEM code. The results were verified and investigated by pressure tests in the hyperbaric chamber of KRISO. It was found that all the estimated results by the empirical formula and FEA are overestimated when the results are compared to the pressure test results in the pressure chamber.

Abstract A38: Modeling ascites-induced changes in peritoneal mechanobiology and ovarian cancer metastatic success

Abstract Ovarian cancer (OvCa) is frequently accompanied by accumulation of intraperitoneal ascites fluid early in disease progression. This fluid is rich in soluble and cellular components including tumor cells and multicellular aggregates (MCAs) of 150-300 um diameter shed from the primary tumor. In addition to chemical cues, ascites fluid buildup can also alter the force environment in the peritoneal cavity, thereby impacting the primary tumor, disseminating cells and MCAs, and host peritoneal tissues. Whereas the intraperitoneal pressure (IPP) of the normal peritoneal cavity is subatmospheric (-5 mmHg), the IPP measured in ovarian cancer patients with tense ascites is reported to be 24 mmHg. The potential effect of ascites-induced changes in peritoneal mechanobiology on tumor cells and host structures has not been investigated due to a lack of appropriate model systems. As a first approximation, we have begun preliminary investigations into the response of tumor and host structures to compressive and strain (stretching) forces. Our initial experiments used MCAs sealed in nonadherent cell culture bags placed into a temperature-controlled stainless-steel pressure vessel and subjected to a compressive force of 22-24 mmHg using an Instron system. While this approach is feasible for short-term experiments, longer-term compression experiments require a system with gas exchange to maintain cell viability. Thus, we fabricated a mold designed to fit within a Flexcell-400C Compression system Biopress+ Bioflex 6-well plate. This mold was used to produce porous hydrogels containing defined void areas so as to encapsulate MCAs within the hydrogel carrier and thereby ensure a more uniform encounter with the Flexcell compression plate. Our initial experiments investigated the effects of MCA compression on gene expression associated with epithelial-to-mesenchymal transition (EMT). Data indicate that short-term static compression (6h) downregulates CDH2 (N-cadherin, Ncad) with cell line-dependent inhibition of EMT regulators including SNAI1, SNAI2, and TWIST. In contrast, long-term compression (24h) upregulated expression of mesenchymal genes including CDH2, MMP14, Wnt5a, ROR1, and ROR2. To examine the impact of strain on receptivity of host peritoneal tissues to metastatic implantation, we used control or strained ex vivo explants of murine peritoneal tissue immobilized on silastic resin. Strained peritoneal tissue exhibited a 3-fold increase in stiffness as determined by atomic force microscopy. Concomitantly, adhesion of ovarian cancer cells to strained peritoneum increased by 4.5-fold. Together these data provide support for a more detailed investigation of the complex role of peritoneal mechanobiology as an important microenvironmental regulator of ovarian cancer metastatic success. Citation Format: Yuliya Klymenko, Rebecca Wates, Yueying LIu, Rachel Lombard, Holly Weiss-Bilka, Leigh Campbell, Diane Wagner, Matthew J. Ravosa, M. Sharon Stack. Modeling ascites-induced changes in peritoneal mechanobiology and ovarian cancer metastatic success. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A38.

The Effect of Strain Hardening on Mechanical Properties of S30408 Austenitic Stainless Steel: A Fundamental Research for the Quality Evaluation of Strain Strengthened Pressure Vessel

The austenitic stainless steel cryogenic pressure vessels are mostly used for the extreme pressure equipment. Strain hardening austenitic stainless steel cryogenic pressure vessels will undergo the plastic deformation during forming and strengthening process. However, the excessive plastic deformation will cause the performance of vessels can not to meet the requirements of related manufacturing and testing standards. Determining the mechanical properties corresponding to the different strain intensities is very important for the safety evaluation of stain strengthened vessels. For normal temperature strain hardening technology, the influence of strain rate on strain hardening and ductility attenuation of austenitic stainless steel cryogenic vessels under normal temperature is studied in this paper, for being used to evaluate the quality and safety performance of the austenitic stainless steel pressure vessel.

Influence of Welding Strength Matching Coefficient and Cold Stretching on Welding Residual Stress in Austenitic Stainless Steel

Austenitic stainless steel is widely used in pressure vessels for the storage and transportation of liquid gases such as liquid nitrogen, liquid oxygen, and liquid hydrogen. Cryogenic pressure vessel manufacturing uses cold stretching technology, which relies heavily on welding joint performance, to construct lightweight and thin-walled vessels. Residual stress from welding is a primary factor in cases of austenitic stainless steel pressure vessel failure. In this paper, on the basis of Visual Environment 10.0 finite element simulation technology, the residual stress resulting from different welding strength matching coefficients (0.8, 1, 1.2, 1.4) for two S30408 plates welded with three-pass butt welds is calculated according to thermal elastoplastic theory. In addition, the stress field was calculated under a loading as high as 410 MPa and after the load was released. Path 1 was set to analyze stress along the welding line, and path 2 was set to analyze stress normal to the welding line. The welding strength matching coefficient strongly affected both the longitudinal residual stress (center of path 1) and the transverse residual stress (both ends of path 1) after the welding was completed. However, the coefficient had little effect on the longitudinal and transverse residual stress of path 2. Under the loading of 410 MPa, the longitudinal and transverse stress decreased and the stress distribution, with different welding strength matching coefficients, was less diverse. After the load was released, longitudinal and transverse stress distribution for both path 1 and path 2 decreased to a low level. Cold stretching could reduce the effect of residual stress to various degrees. Transverse strain along the stretching direction was also taken into consideration. The experimental results validated the reliability of the partial simulation.

Performance of metal and polymeric O-ring seals during beyond-design-basis thermal conditions

This paper summarizes the small scale thermal exposure test results of the performance of metallic and polymeric O-ring seals typically used in radioactive material transportation packages. Five different O-ring materials were evaluated: Inconel/silver, ethylene-propylene diene monomer (EPDM), polytetrafluoroethylene (PTFE), silicone, butyl, and Viton. The overall objective of this study is to provide test data and insights to the performance of these O-ring seals when exposed to beyond-design-basis temperature conditions due to a severe fire. Tests were conducted using a small-scale stainless steel pressure vessel pressurized with helium to 2 bar or 5 bar at room temperature. The vessel was then heated in an electric furnace to temperatures up to 900 °C for a pre-determined period (typically 8 h–9 h). The pressure drop technique was used to determine if leakage occurred during thermal exposure. Out of a total of 46 tests performed, leakage (loss of vessel pressure) was detected in 13 tests.

An Empirical Life Prediction Method of Cold-Stretched Austenitic Stainless Steel

With the purpose of long-cycle safe operation of cold stretched austenitic stainless steel pressure vessels so as to achieve unification of economy and safety, prediction of fatigue life of S31603 austenitic stainless steel at high temperature is systematic studied. Based on the Hull-Rimmer cavity theory, a fatigue life prediction model applicable to stress controlled is developed. Fatigue test is carried out on the solution annealed and cold stretched S31603 steel at high temperature and corresponding test data is obtained. The fatigue life of the solution annealed and cold stretched materials is predicted by the model and the prediction results are in good agreement with the experimental results. On this basis, the life prediction model coupled with the strain level of cold stretching is further established. Compared with the test data, the prediction results is found to be very satisfactory with an error band less than ±1.5 times. The fatigue life prediction model suitable for stress control at high temperature is simple in form and has a clear and obvious physical significance which points out a new way to predict fatigue life of metal materials.

The effect of hydrostatic pressure on the decomposition of inundated terrestrial plant detritus of different quality in simulated reservoir formation

AbstractThe formation of reservoirs usually incorporates the inundation of terrestrial vegetation in the basin. The decomposition of organic matter from the flooded vegetation may have several implications for reservoir functioning, including eutrophication and dissolved oxygen depletion. The hydrostatic pressure increases with depth in a reservoir, and its influence on the decomposition process has not previously been evaluated. This study was undertaken to evaluate the decomposition of terrestrial plant detritus of different qualities (leaves and branches) under different hydrostatic pressure conditions. Detritus were placed separately in glass bottles in the laboratory and incubated in tight stainless steel pressure vessels, simulating three different depths (surface, 30 and 100 m). The masses (mg) of particulate organic carbon (POC), dissolved organic carbon (DOC) and inorganic carbon (IC) were determined for the 4 months of the detritus decomposition simulated in this study. The mass values were transformed in percentages of the initial detritus carbon. The results of temporal variations of the compounds studied were fitted to a first‐order biphasic decay model. The hydrostatic pressure exhibited no significant effects on litter decomposition. On the other hand, the detritus chemical composition (i.e. the presence of labile and refractory compounds) was the determining factor for the decomposition curve shape and for the differences observed between the leaves and branches. The greatest POC loss from leaves, and resulting larger DOC mass, indicated the leaves were more labile than the branches. The results also indicated the branches are the main detritus remaining in a reservoir over time.

Analytical and finite element modeling of pressure vessels for seawater reverse osmosis desalination plants

A pressure vessel (PV) which contains the membrane elements of seawater reverse osmosis (SWRO) desalination has been modeled using analytical solution and finite element modeling (FEM) to optimize the PV design parameters. Two types of PV materials have been compared namely; stainless steel and fiber reinforced composite materials. Von-Mises yield criterion and Tsai-Wu failure criterion are used for the design of stainless steel and composite PVs respectively. E-glass/epoxy and carbon/epoxy composite materials are considered in this work. In addition, hybrid composite materials are introduced for layers through the vessel thickness. The results have shown that the optimum lay-up is achieved using the angle-ply [±ϴ]ns at winding angle of 54° for E-glass/epoxy and 55° for carbon/epoxy PVs while for hybrid composite PVs the optimum lay-up is [90G/±50C/90G]ns. Also, the results have shown that the composite PVs have lighter weight than the stainless steel PVs. The carbon/epoxy PVs introduce the optimum weight savings but in terms of the total PVs cost, the hybrid composite PVs can be used.

True stress and shakedown analysis of pressure vessel under repeated internal pressure

This study aims to investigate the true stress and the plastic shakedown behavior of a cyclically loaded pressure vessel. To serve this study, an experimental platform has been built up, which comprised of a self-made thin-wall cylinder pressure vessel, a water pressure loading system to simulate the actual working loading condition, and strain gauge sets for strain measurement. A number of experiments have been done by cyclically loading and unloading the vessel at different strain levels of plastic deformation to shakedown state in different experiments respectively. The relationship between plastic strain and shakedown range has therefore been obtained. The true stress-strain constitutive model of the vessel under large deformation condition has also been derived. The experiments lead to three observations: (1) the strain hardening technology can effectively reduce the residual stress of stainless steel pressure vessel. (2) The shakedown range is less than 2000 μe for a total strain under 4%, and yet the shakedown range increases fast to more than 3000 μe for a total strain higher than 6%. (3) It is also found that the true stress-strain constitutive model given in this paper describes the multi-axial stress-strain state of pressure vessels, and validates the engineering practicability of conventional uniaxial tensile shakedown constitutive curve.

Infrared thermography-based studies on hydrotesting of stainless steel pressure vessels

Infrared thermography-based studies on hydrotesting of stainless steel pressure vessels

Modular Design and Experimental Testing of a 50 kWth Pressurized-Air Solar Receiver for Gas Turbines

A high-temperature high-concentration pressurized-air solar receiver is considered for driving a power generation Brayton cycle. The modular design consists of a cylindrical SiC cavity surrounded by a concentric annular reticulated porous ceramic (RPC) foam contained in a stainless steel pressure vessel, with a secondary concentrator attached to its windowless aperture. Experimentation was carried out in a solar tower for up to 47 kW of concentrated solar radiative power input in the absolute pressure range of 2-6 bar. Peak outlet air temperatures exceeding 1200 °C were reached for an average solar concentration ratio of 2500 suns. A notable thermal efficiency—defined as the ratio of the enthalpy change of the air flow divided by the solar radiative power input through the aperture—of 91% was achieved at 700 °C and 4 bar.

Investigation on Mechanical Behaviors of Cold Stretched and Cryogenic Stretched Austenitic Stainless Steel Pressure Vessels

Austenitic stainless steel is widely used in pressure vessels for storage of liquid gas, such as LN2, LO2, LH2. To make wall thin and weight light, cold stretching technology is applied in cryogenic pressure vessel manufacture. Cold stretching is performed by pressurizing a vessel to a specific pressure and maintaining the pressure for a moment to produce a certain amount of plastic deformation, so that the yield strength of the vessel material could be strengthened after releasing the pressure. Cryogenic stretching is similar in principle to cold stretching, but the medium is liquid nitrogen instead of water in cold stretching. Cold stretching has been recorded in standards such as Cold-Stretching Directions 1991, AS 1210-Supp2-1999, EN 13458-2:2002, EN 13530-2:2002, ASME BPVC VIII-I Code Case 2596, ISO 20421-1:2006, ISO 21009-1:2008. Nevertheless, cryogenic stretching is not applied in pressure vessels manufacture due to lack for detailed investigation. To investigate mechanical behaviors of cold stretched and cryogenic stretched austenitic stainless steel pressure vessels, a series of tests for S30403 were performed at 20°C (temperature in which cold stretching proceeds) and -196°C (temperature in which cryogenic stretching proceeds), the difference of martensite transformation, strength and plasticity in which were compared. Finite element analysis method based on MISO model was used to simulate cold stretching process of pressure vessel, including the process of loading to strengthening pressure, unloading to no-load state and reloading to design pressure. Considering material properties difference, different types of strengthening pressure methods for cryogenic stretching were performed to confirm a rational strengthening pressure value. Mises equivalent stress, tresca equivalent stress, circumferential stress, axial stress and deformation were taken into consideration. The investigation has shown that compared with cold stretching, cryogenic stretching could improve material properties more significantly. In other words, pressure vessels could have thinner wall and lighter weight after cryogenic stretching.

Ultrasonic stress evaluation through thickness of a stainless steel pressure vessel

This paper investigates ultrasonic method in stress measurement through thickness of a pressure vessel. Longitudinal critically refracted (LCR) waves are employed to measure the welding residual stresses in a vessel constructed from austenitic stainless steel 304L. The acoustoelastic constant is measured through a hydro test to keep the pressure vessel intact. Hoop and axial residual stresses are evaluated by using different frequency range of ultrasonic transducers. The welding processes of vessel shell and caps are simulated by a 3D finite element (FE) model which is validated by hole-drilling method. The residual stresses calculated by FE simulation are then compared with those obtained from the ultrasonic measurement while a good agreement is observed. It is demonstrated that the residual stresses through thickness of the stainless steel pressure vessel can be evaluated by combining FE and LCR method (known as FELCR method).