Comparison of Numerical Methods for Strain Based ECA

2015 ◽  
Author(s):  
Josef Navarro ◽  
Andrew Low ◽  
Thao (Joe) Tran
Keyword(s):  
Numerical Methods ◽  
Pipe Material ◽  
Corrosion Resistant ◽  
Design Life ◽  
Failure Assessment ◽  
Corrosion Resistant Alloy ◽  
Pipe Joints ◽  
Girth Welds ◽  
Mn Steel ◽  
Numerical Approaches

The integrity of subsea pipe girth welds is routinely ensured through Engineering Criticality Assessments (ECAs) based on fracture mechanics principles. In order to capture the whole design life, the ECA must cover loadings that the pipeline is subjected to during both installation and operation. Stress based semi-analytical methods using Failure Assessment Diagrams (FAD) have been used extensively for ‘run of the mill’ assessments as far as C-Mn steel pipe with overmatching weld is concerned. These stress based methods are captured in depth in industry codes such as BS7910 and DNV-OS-F101. In recent years however, with industry seeking to transport more corrosive fluids, the use of pipe containing a corrosion resistant alloy (CRA) layer is becoming increasingly popular. Together with the CRA layer, anti-corrosion weld consumables material would be used at the pipe joints to protect the whole pipeline from corrosion. Some of these weld consumables, especially at high temperature, partially overmatch or even undermatch the parent pipe material, resulting in difficulties in application of conventional FAD approach. Industry has turned to numerical methods to fill in gaps which are not covered by the FAD based approach. However no codified approach/standard exists for executing numerically based ECAs. This paper attempts to outline the FAD and numerical approaches being used by industry. The different approaches will be assessed for their range of application, limitations of execution and comparison of results obtained. The study is carried out for the case of a typical external surface flaw in a 12″ pipe.

Design and Welding Challenges in the Infield Flowlines of the Encana Deep Panuke Development

2010 ◽  
Author(s):  
Kenneth A. Macdonald ◽  
Craig Russell
Keyword(s):  
Structural Design ◽  
Steel Substrate ◽  
Pipe Material ◽  
Corrosion Resistant ◽  
Acid Gas ◽  
Industry Research ◽  
Offshore Pipeline ◽  
Clad Layer ◽  
Design Loads ◽  
Corrosion Resistant Alloy

Designing and constructing subsea flowlines to address the implications of aggressive hydrocarbon well fluids — and selecting suitably corrosion-resistant materials for such applications — typically proves challenging and often leads to the specification of clad, lined, or solid corrosion resistant alloy (CRA) linepipe materials. Design and construction guidance for such flowline systems is presently not comprehensive in offshore pipeline standards, even for cases where the thickness of the CRA layer is ignored in the structural design. Acergy are designing, procuring and installing a series of technically challenging infield flowlines within the Encana Deep Panuke gas prospect located off the coast of Sable Island, Nova Scotia. Presently being developed, first gas from the Deep Panuke field is scheduled for the third quarter of 2010 following the tie-in of the infield flowlines to their respective subsea production wellheads. These flowlines are to be installed using the Acergy Falcon, a vessel which has an installation system based on a variable angle J-lay principle and plastic deformation of the pipe. The four 8in production flowlines are clad linepipe comprising a 12.5 mm WT grade 415 (X60) carbon steel substrate with an internal 2.5mm Incoloy Alloy 825 clad layer that is metallurgically bonded to the mother pipe. The single 3in acid gas flowline is solid Inconel Alloy 625. The nominal level of installation plastic strain for the project ranges up to 1.675% in the case of the 8in line. Both lines will be welded by manual GTAW using Inconel 686 filler material. The pipelines are designed and fabricated in accordance with DNV OS-F101 supplemented by new guidance emerging from a DNV joint industry project on clad and lined materials. Metallurgically clad and mechanically bonded (lined) products present a mixture of common and unique challenges when designing and welding flowlines. The existing production limits for pipe dimensions in clad material have for some time now existed on the very cusp of design requirements, especially when using only the thickness of the steel substrate to resist the design loads. Indeed, recently the design demands of some projects have clashed with the available linepipe geometry and the mechanical properties of the clad layer material have of necessity been taken account of in the structural design. The dominant offshore design code, DNV OS-F101, is presently unable to offer specific guidance for including the clad layer and it is only in 2009 that joint industry research has established a viable design methodology for pressure containment wall thickness design which includes the strength effect of the clad layer. In addition to discussing the Deep Panuke design challenges and the welding philosophy for clad pipe, this paper also draws on approaches to welding and NDT successfully taken for the Statoil Tyrihans project in Norway, which used lined pipe material. The general welding philosophy adopted accommodates the continued inability of AUT systems to reliably inspect CRA weldments without false indications from normal metallurgical weld features. A proven approach is taken using intermediate inspection of the root and hot pass using real-time radiography (RTR); effecting any repairs needed; and then re-inspecting the weld upon fill and completion using RTR again. The importance of — and difficulty in — achieving adequate weld metal yield strength in CRA weldments is also discussed.

scholarly journals Ultimate Axial Load Prediction Model for X65 Pipeline with Cracked Welding Joint Based on the Failure Assessment Diagram Method

2021 ◽  
Vol 11 (24) ◽  
pp. 11780
Author(s):  
Jianping Liu ◽  
Hong Zhang ◽  
Shengsi Wu ◽  
Xianbin Zheng ◽  
Dong Zhang ◽  
...  
Keyword(s):  
Axial Load ◽  
Support Vector ◽  
Pipe Material ◽  
Safe Operation ◽  
Diagram Method ◽  
Factors Affecting ◽  
Failure Assessment Diagram ◽  
Comparison Results ◽  
Failure Assessment ◽  
Girth Welds

Crack defects in the girth welds of pipelines have become an important factor affecting the safe operation of in-service oil pipelines. Therefore, it is necessary to analyze the factors affecting the safe operation of pipelines and determine the ultimate load during pipeline operation. Based on the failure assessment diagram (FAD) method described in the BS 7910 standard, the key factors affecting the evaluation results of the suitability of X65 pipeline girth welds are analyzed, and the effects of crack size, pipe geometry, and material properties on the evaluation results are investigated. The results indicate that the crack depth is more crucial to the safe operation of the pipeline than the crack length. While the effect of wall thickness is not significant, the misalignment can seriously aggravate the stress concentration. In general, the higher the yield ratio and tensile strength of the pipe material, the more dangerous the condition at the weld. The ultimate axial load that a crack-containing girth weld can withstand under different combinations of the above factors was determined. Furthermore, a data driven model via the optimized support vector regression method for the ultimate axial load of the X65 pipe was developed for engineering application, and the comparison results between the FEM results and the predicted results proved its accuracy and reliability.

Review of the In-Air Fatigue Behaviour of CRA Clad and Lined Pipe

2019 ◽  
Author(s):  
Carol Johnston ◽  
Jenny Crump
Keyword(s):  
Carbon Steel ◽  
Fatigue Behaviour ◽  
Full Scale ◽  
Fatigue Performance ◽  
Steel Pipe ◽  
Corrosion Resistant ◽  
Resistant Alloy ◽  
Corrosion Resistant Alloy ◽  
Girth Welds

Abstract Pipe internally clad or lined with corrosion resistant alloy (CRA) is used offshore when production fluid contains H2S and/or CO2 to protect the carbon-steel pipe from corrosion. Girth weld classification in standards such as BS7608 and DNVGL-RP-C203 do not specifically include clad and lined pipes but their fatigue performance is relevant to designers of these pipelines. This paper first reviews available literature on the in-air fatigue performance of clad and lined girth welds. Data from the literature as well as full scale resonance fatigue results from tests carried out at TWI are then analysed so that recommendations can be made on a suitable fatigue classification. Finally, areas are highlighted where more research into clad and lined pipe is needed.

SANICRO 41

Alloy Digest ◽  
1995 ◽  
Vol 44 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Oil And Gas ◽  
High Strength ◽  
Heat Treating ◽  
Gas Production ◽  
Oil And Gas Production ◽  
Corrosion Resistant ◽  
Corrosion Resistant Alloy ◽  
Nickel Base

Abstract SANDVIK SANICRO 41 is a nickel-base corrosion resistant alloy with a composition balanced to resist both oxidizing and reducing environments. A high-strength version (110) is available for oil and gas production. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ni-475. Producer or source: Sandvik.

INCONEL ALLOY 22

Alloy Digest ◽  
2005 ◽  
Vol 54 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Pitting Corrosion ◽  
Corrosion Resistant ◽  
Inconel Alloy ◽  
Resistant Alloy ◽  
Alloy 22 ◽  
Corrosion Resistant Alloy

Abstract Inconel alloy 22 is an advanced corrosion-resistant alloy with exceptional resistance to aqueous and pitting corrosion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as joining. Filing Code: Ni-624. Producer or source: Special Metals Corporation.

INCO-WELD 725NDUR

Alloy Digest ◽  
1998 ◽  
Vol 47 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Tensile Properties ◽  
Filler Metal ◽  
Heat Treating ◽  
Oil Exploration ◽  
Corrosion Resistant ◽  
Resistant Alloy ◽  
Corrosion Resistant Alloy

Abstract Inco-Weld 725NDUR filler metal is a corrosion-resistant alloy similar to Inconel Filler Metal 625 (see Alloy Digest Ni-327, December 1985) but with higher strength and hardness. Applications include the oil exploration down-hole equipment market. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating and joining. Filing Code: Ni-540. Producer or source: Inco Alloys International Inc.

ALLEGHENY LUDLUM AL 29-4C

Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Exchangers ◽  
Power Plants ◽  
High Strength ◽  
Corrosion Resistant ◽  
Resistant Alloy ◽  
Corrosion Resistant Alloy ◽  
Geothermal Power

Abstract AL 29-4C is a highly corrosion resistant alloy with a relatively high strength. This combination allows the use of lighter gage tubes, and has led to its use in the brine heat exchangers of geothermal power plants. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-554. Producer or source: Allegheny Ludlum Corporation.

FIRTH VICKERS F.I. (A1)

Alloy Digest ◽  
1970 ◽  
Vol 19 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stainless Steels ◽  
Heat Treating ◽  
Oil Refining ◽  
Corrosion Resistant ◽  
Temperature Performance ◽  
Plant Equipment ◽  
Corrosion Resistant Alloy

Abstract FIRTH VICKERS FI (A1) is a chromium type heat and corrosion resistant alloy steel recommended for oil refining and chemical plant equipment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-236. Producer or source: Firth-Vickers Stainless Steels Ltd.

COOPER ALLOY 14S

Alloy Digest ◽  
1964 ◽  
Vol 13 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Corrosion Resistant ◽  
Temperature Performance ◽  
Corrosion Resistant Alloy

Abstract Cooper Alloy 14S is an abrasion, heat and corrosion resistant alloy steel containing 12% chromium. It can be hardened by heat treatment. It is recommended for pumps and valves in the cast form. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: SS-158. Producer or source: Cooper Alloy Corporation.

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