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Collaborating Authors
Steel
Abstract Thick-walled steel pipes manufactured through the UOE process are used in deep-water pipeline applications for the safe and cost-effective transmission of hydrocarbon energy resources. Such pipes are subjected to bending loads in the presence of high external pressure during their installation stage. The combination of bending and external pressure often triggers the development of structural instability due to excessive ovalization of the pipe with catastrophic effects. In the present study, the effect of UOE line pipe manufacturing process on the bending response of externally-pressurized thick-walled pipes is examined, using finite element simulation tools.
- Europe (1.00)
- North America > United States > Texas (0.28)
- Energy > Oil & Gas > Upstream (0.49)
- Materials > Metals & Mining > Steel (0.35)
Abstract Mechanically bonded lined steel pipelines are considered to be technically viable and cost effective for field developments with sour service. In these pipelines, a 3mm layer of Corrosion Resistant Alloy (CRA) layer is used typically to form the internal lining. Recent developments, including DNV JIP on Lined and Clad Pipelines, consider for lined pipes the CRA layer is utilised only for pressure containment calculations. The current design practice does not include consideration of possible beneficial strengthening effect of liner on steel pipe for installation and operating conditions. This paper presents the moment-nominal strain for the lined and clad pipes for varying strain levels representative of buckle curvature. The lined pipe was modelled from manufacturing process to capture the evolution of material properties correctly. The effect of the relatively high tensile strength of lined pipes due to cold hydraulic expansion inherent in the manufacturing process was considered in the analysis. The heating process of the pipeline during corrosion coating may lead to almost ‘no grip’ condition for typical lined pipe with 316L liner. Further at the apex of the buckle, the liner is in ‘full grip’ condition on tension side and ‘low grip’ condition on compression side due to curvature effects. Similar behaviour is noted for installation condition. The results from two models with and without liner are compared to study the effect of presence of liner. The possible failure modes predominant in the pipes for different D/t ratios are discussed.
- Materials > Metals & Mining > Steel (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Effect of Martensite–Austenite Constituent Under Simulated Welding Conditions on Low-Temperature Toughness and Microstructure of SMYS 500-MPa-Class Offshore Structural Steel Plate
Kim, In (Dongkuk Steel R&D Center, Pusan National University) | Jo, Seung-Jae (Dongkuk Steel R&D Center) | Jo, Soo-Chal (Dongkuk Steel R&D Center) | Kang, Ki-Bong (Dongkuk Steel R&D Center) | Kang, Nam-Hyun (Pusan National University)
Abstract Most offshore structural projects require multilayer welding owing to the use of thick plates and the maximum heat input limit (<50 kJ/cm in offshore fields). It is generally known that toughness decreases in the following two regions of the welded heat-affected zone (HAZ): coarsegrained heat-affected zone (CGHAZ) and intercritically reheated coarse-grained heat-affected zone (IRCGHAZ). Moreover, the formation of the martensite-austenite (M-A) constituent in the welded HAZ is an important phenomenon that greatly decreases the toughness in this zone. Therefore, in order to improve toughness, it is very important to control the fraction and shape of the M-A constituent. In this study, a test plate (specified minimum yield strength, SMYS: 500 MPa) was fabricated by direct quenching and tempering process. Differently simulated weld thermal cycles for CGHAZ and IRCGHAZ were carried out using a Gleeble tester. In order to determine the relationship between simulated and real HAZ, real welded joints were also fabricated. Microstructure observations and phase fraction measurements were carried out for these joints. The obtained results showed that low-temperature toughness in welded HAZ increased in proportion to that in the fine-grained heat-affected zone (FGHAZ) owing to the passes employed during the multi-pass welding; in contrast, the toughness in welded HAZ decreased in proportion to that in IRCGHAZ fraction.
- Energy > Oil & Gas > Upstream (0.68)
- Materials > Metals & Mining > Steel (0.54)
Microstructural Aspects of Bainite-MA Type Dual-Phase Steel for the Strain-Based Design in Terms of Deformation and Fracture
Ishikawa, Nobuyuki (JFE Steel Corporation) | Shimamura, Junji (JFE Steel Corporation) | Yasuda, Kyono (JFE Steel Corporation) | Nakamichi, Haruo (JFE Steel Corporation) | Endo, Shigeru (JFE Steel Corporation) | Tsuyama, Seishi (JFE Steel Corporation)
Abstract Linepipe with the dual-phase steel of bainite and dispersed MA (martensite-austenite constituent) phases has been applied for many pipelines in the seismic and permafrost regions which require higher deformability of the linepipes. Bainite-MA dual-phase microstructure exhibits excellent deformability and high strength up to Grade X100. Finely dispersed MA phases in the bainitic matrix also show strong resistance to microscopic crack initiation and propagation, resulting in good toughness of the base metal. This paper introduces metallurgical features of the bainite-MA type dual-phase steel with exploring microscopic deformation and fracture behaviors.
Abstract Detrimental hydrogen in the weld reduces its ductility and increases the possibility of cold cracking. The objective of this study has been to use computer simulations to predict residual stresses and decay of hydrogen in and adjacent to a 10 cm test weld which closes the gap between the sleeve and the pipe in a part-size sleeve-on-pipe mock-up for subsea pipeline repair applications. Pre- and post-weld heat treatment was applied to the test geometry which was designed to replicate the highest restraint level of a remote pipeline repair scenario. Two cases from the experiments were chosen for modeling, one successful that produced a weld free for cracks and another which was given a lower PWHT temperature that generated a level of hydrogen assisted cracking. With respect to the incidence of cracking and the position where the crack was initiated, the microstructure composition, the tensile stresses and the level of hydrogen predicted by the computer model is considered to support the experimental findings.
- Europe > Norway (0.46)
- Europe > United Kingdom (0.28)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/11 > Åsgard Field > Åre Formation (0.99)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/11 > Åsgard Field > Tofte Formation (0.99)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/11 > Åsgard Field > Tilje Formation (0.99)
- (39 more...)
Abstract Within a European research project, which aims to provide economic and safe guidance for the design of Combined Walls, large four point bending tests have been performed to investigate local buckling behavior of such pipes. The tests are performed on pipes with 1067 mm diameter and D/t ratios ranging from 67 to 119 in steel grades X52 to X70. In addition to the spirally welded pipes, two longitudinally welded specimens of similar slenderness and steel grade have been tested to compare the effect of the two production methods on the local buckling behavior. Results show that there are some interesting differences between the behavior of spirally welded and longitudinally welded pipes loaded in bending. Furthermore, it is shown that the use of strain based design is applicable in this application area of relatively high D/t ratios.
- Europe (0.46)
- North America (0.28)
- Research Report > New Finding (0.34)
- Research Report > Experimental Study (0.34)
- Energy > Oil & Gas (0.69)
- Materials > Metals & Mining > Steel (0.55)
Abstract In this study the stochastic properties of the response of a steel plate under in-plane compressive load subject to random initial deformation has been characterized using Polynomial Chaos Expansions (PCE). Initially the random characteristics of maximum initial deformation of a steel plate have been evaluated using PCE. Subsequently an analytical procedure has been developed which can predict the stochastic characteristics of the strength of plate, based on the probabilistic model of the initial deformation. A significant feature of the present method is the avoidance of the generally time-consuming Monte Carlo Simulation. It has been found that the proposed methodology can predict the statistical characteristics of the plate response with sufficient accuracy, when compared to those obtained from Monte Carlo Simulations.
Abstract The low-cycle fatigue behaviour of butt welded plates made of S960QL, and S1100QL is presented in this paper. Specimens in as welded condition and post-weld treated specimens are considered as well as the influence of yield strength on the low-cycle fatigue behavior. Summarized evaluation and comparison with regard to different post weld treatment methods such as TIG-dressed, high frequency hammer peened and ground welds are worked out. The results are discussed referring to fatigue class classification of Eurocode 3 and the recent IIW guideline.
Proposal of Test Method for Brittle Crack Arrest Toughness, Kca - Study on Standard Test Method for Crack Arrest Toughness, Kca -1-
Shimada, Yusuke (Nippon Steel and Sumitomo Metal Corp.) | Inoue, Takehiro (Nippon Steel and Sumitomo Metal Corp.) | Kawabata, Tomoya (Nippon Steel and Sumitomo Metal Corp.) | Handa, Tsunehisa (JFE Steel Corporation ) | Kaneko, Masahito (Kobe Steel, LTD) | Sugimoto, Kei (Nippon Kaiji Kyokai) | Aihara, Shuji (Tokyo University) | Shibanuma, Kazuki (Tokyo University)
Abstract Run-arrest behavior of brittle crack in steel has been investigated since a lot of severe accidents by brittle failure. In order to evaluate arrest toughness of materials, various test methods were developed. At the moment temperature gradient type ESSO test is the most popular method for the determination of arrest toughness of material used because of its convenience. However, there is no code or standard ESSO test despite its long history. In these last three years, the working group whose aim is to establish the new standard of arrest toughness test has been activated in the Japan Welding Engineering Society. Finally, new standard was published in January 2014 as JWES standard.
- Materials > Metals & Mining > Steel (0.71)
- Energy > Oil & Gas > Upstream (0.47)
Onshore Pipeline High-grade Steel for Challenge Utilization
Ferino, Jan (Centro Sviluppo Materiali SpA) | Fonzo, Andrea (Centro Sviluppo Materiali SpA) | Di Biagio, Massimo (Centro Sviluppo Materiali SpA) | Di Biagio, Giuseppe (Centro Sviluppo Materiali SpA) | Karamanos, Spryos A. (University of Thessaly) | Spinelli, Carlo Maria (eni S.p.A)
Abstract High pressure pipeline transportation is one of the key technologies to connect remote gas fields and deliver gas at competitive prices to consumption markets. Arctic regions will become more attractive in the near future as large gas resources are located there. Long onshore pipelines systems, characterized by high strength steels (above API 5L X80, i.e. exceeding 555 MPa Yield Strength) operated at high internal gas pressure (more than 10–12 MPa) in many cases appear to be the most convenient transportation option. This paper highlights the latest follow up coming from a long lasting R&D program launched by eni, together with industrial/technical partners, on the exploitation of commercial available options with high grade steels for onshore application even in harsh environments. The results obtained in this R&D program can be useful for applications even for arctic onshore/offshore scenario.
- Europe (1.00)
- North America > United States (0.70)