Effect of Girth Welding on Strain Capacity of X80 SAW Pipes

2014 ◽  
Author(s):  
Hidenori Shitamoto ◽  
Eiji Tsuru ◽  
Hiroyuki Nagayama ◽  
Nobuaki Takahashi ◽  
Yuki Nishi
Keyword(s):  
Matching Condition ◽  
Construction Cost ◽  
Bending Test ◽  
Long Distance ◽  
Strain Capacity ◽  
Girth Welding ◽  
Girth Welds ◽  
Welded Pipe ◽  
Submerged Arc ◽  
Pipe Bending

Application of API X80 grade line pipes has been promoted to reduce a construction cost of the pipeline. Assessment of the strain capacity of X80 submerged arc welded (SAW) pipe is required for strain-based design (SBD). Long distance gas pipelines are usually constructed using girth welded line pipes. In the assessment of the strain capacity, it is important to keep over-matching at girth welds. However, since strength variation exists in base metal and girth weld metal, the value of the matching ratio also changes. In this study, X80 SAW pipes produced by the UOE process were welded under slightly over-matching condition and full-scale pipe bending test of the girth welded pipe was performed to evaluate the effect of the matching ratio on the strain capacity.

Pipe Bending Test With Girth Welding on X80 Grade SAW Pipes

2010 ◽  
Author(s):  
Masahiko Hamada ◽  
Hidenori Shitamoto ◽  
Shuji Okaguchi ◽  
Nobuaki Takahashi ◽  
Izumi Takeuchi ◽  
...  
Keyword(s):  
Full Scale ◽  
Bending Test ◽  
Test Program ◽  
Bending Tests ◽  
Girth Welding ◽  
Manufacturing Procedure ◽  
Girth Welds ◽  
Welding Procedure ◽  
Pipe Manufacturing ◽  
Pipe Bending

This study was planned as a part of a test program to confirm the effect of girth welds on the strain capacity of pipes. In this study, full-scale pipe bending tests are performed by using X80 SAW pipe. This paper covers pipe manufacturing procedure, developed welding procedure to obtain even match weld metal and properties of welded joints. And this work demonstrated that the X80 pipes welded under the developed procedure fractured in base metal remote from girth welded portion by full scale pipe bending test conducted under the internal pressure of 72% SMYS of X80.

Effect of Thermal Aging on Strain Capacity of X80 SAW Pipes

2012 ◽  
Author(s):  
Hidenori Shitamoto ◽  
Masahiko Hamada ◽  
Nobuaki Takahashi ◽  
Yuki Nishi
Keyword(s):  
Thermal Aging ◽  
Arc Welding ◽  
Submerged Arc Welding ◽  
Full Scale ◽  
Operating Pressure ◽  
Bending Tests ◽  
Strain Capacity ◽  
Submerged Arc ◽  
Pipe Bending

Application of API X80 grade line pipes has been promoted to increase the operating pressure. It is generally known that the deformability of submerged arc welding (SAW) pipes is decreased by increasing strength of the pipes. The assessment of the strain capacity of X80 SAW pipes is required for strain-based design (SBD). In the assessment of the strain capacity, one of the important issues is the effect of thermal aging during the anti-corrosion coating on the yielding phenomenon. In this study, full-scale pipe bending tests of X80 SAW pipes produced by UOE process were performed to evaluate the effect of thermal aging on the strain capacity.

Girth Weld Strength Matching Effect on Tensile Strain Capacity of Grade X70 High Strain Line Pipe

2018 ◽  
Author(s):  
Hisakazu Tajika ◽  
Takahiro Sakimoto ◽  
Tsunehisa Handa ◽  
Rinsei Ikeda ◽  
Joe Kondo
Keyword(s):  
High Strain ◽  
Limit State ◽  
Full Scale ◽  
Bending Test ◽  
High Grade ◽  
Line Pipe ◽  
Bending Tests ◽  
Strain Capacity ◽  
Pipeline Project ◽  
Pipe Bending

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipes with size of 36″ OD and 23mm WT was investigated with two types of experiments, which are full scale pipe bending tests and curved wide plate tests. The length of the specimen of full scale bending tests were approximately 8m and girth weld was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. Test pipes were cut and welded, GTAW in first two layer and then finished by GMAW. In one pipe, YS-TS over-matching girth weld (OVM) joint was prepared considering the pipe body grade. For the other pipe, intentionally under-matching girth weld (UDM) joint was prepared. After the girth welding, elliptical EDM notch were installed in the GW HAZ as simulated weld defect. In both pipe bending tests, the buckling occurred in the pipe body at approximately 300mm apart from the GW and after that, deformation concentrated to buckling wrinkle. Test pipe breaking locations were different in the two tests. In OVM, tensile rupture occurred in pipe body on the backside of buckling wrinkle. In UDM, tensile rupture occurred from notch in the HAZ. In CWP test, breaking location was the HAZ notch. There were significant differences in CTOD growth in HAZ notch in these tests.

Evaluation of Hydrogen Cracking Susceptibility in X120 Girth Welds

2004 ◽  
Author(s):  
M. L. Macia ◽  
D. P. Fairchild ◽  
J. Y. Koo ◽  
N. V. Bangaru
Keyword(s):  
Laboratory Tests ◽  
High Strength ◽  
Test Method ◽  
Laboratory Studies ◽  
Long Distance ◽  
Hydrogen Cracking ◽  
Girth Welding ◽  
Groove Test ◽  
Girth Welds ◽  
The Cost

To reduce the cost of long distance gas transmission, high strength pipeline steels are being developed. Implementation of high strength pipeline materials requires the avoidance of hydrogen cracking during field girth welding. A study of hydrogen cracking in X120 girth welds has been conducted. Cracking resistance of both the weld metal and heat affected zone (HAZ) were investigated. The laboratory tests included the controlled thermal severity (CTS) test, the WIC test and the Y-groove test. In addition, multi-pass plate welds and full pipe welds were completed and examined for the presence of hydrogen cracks. The suitability of each test method for predicting cracking in X120 girth welds is determined. The morphology of hydrogen cracks in X120 girth welds is described, and the conditions necessary to prevent hydrogen cracking are identified. Following the laboratory studies, construction of X120 pipelines without cracking was demonstrated through a 1.6 km field trial.

Attributes of Modern Linepipes and Their Implications on Girth Weld Strain Capacity

2018 ◽  
Author(s):  
Yong-Yi Wang ◽  
Steve Rapp ◽  
David Horsley ◽  
David Warman ◽  
Jim Gianetto
Keyword(s):  
Tensile Properties ◽  
Weld Strength ◽  
Potential Contribution ◽  
Contributing Factors ◽  
Strain Capacity ◽  
Strain Tolerance ◽  
Industry Standards ◽  
Girth Welding ◽  
Girth Welds ◽  
Welding Procedure

There has been a number of unexpected girth weld failures in newly constructed pipelines. Girth weld failures have also been observed in pre-service hydrostatic testing. Post-incident investigations indicated that the pipes met the requirements of industry standards, such as API 5L. The welds were qualified per accepted industry standards, such as API 1104. The field girth welding was performed, inspected, and accepted per industry standards, such as API 1104. Some of the traditional causes of girth weld failures, such as hydrogen cracks and high-low misalignment, were not a factor in these incidents. This paper starts with a review of the recent girth weld incidents. A few key features of a failed weld and their implications are examined. The characteristics of the recent failures is summarized, and the major contributing factors known to date are given. Some of the options to prevent future failures include (1) changes to the tensile properties of the pipes and enhanced hardenability, (2) welding options aimed at increasing the weld strength and minimizing heat-affected zone (HAZ) softening, and (3) reduction of stresses on girth welds. This paper focuses on the first two options. The trends of chemical composition and tensile properties of linepipe are reviewed. The potential contribution of these trends to the girth weld incidents is examined. Possible changes to the linepipe properties and necessary updates in the testing and qualification requirements of the linepipes are provided. Welding options beneficial to enhanced girth weld strain capacity are discussed. Possible revisions to welding procedure qualification requirements, aimed at achieving a minimum level of strain tolerance/capacity, are proposed. The application of previously developed tools in estimating the propensity of HAZ softening is reviewed.

Evaluation of Compressive Strain Limit of X80 Saw Pipes With Girth Welding by FE Analysis

2010 ◽  
Author(s):  
Hidenori Shitamoto ◽  
Masahiko Hamada ◽  
Shuji Okaguchi ◽  
Nobuaki Takahashi ◽  
Izumi Takeuchi ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
High Strength ◽  
Environmental Conservation ◽  
Ground Movement ◽  
Bending Test ◽  
Line Pipe ◽  
Strain Capacity ◽  
Girth Welding ◽  
Transmission Pipelines

The expansion of supply capacity of natural gas to market is expected from the concern of environmental conservation by less CO2 emission. Transportation cost has been focused for natural gas to be competitive in the market. High-pressure gas pipelines have constructed by large diameter and high strength line pipes to improve transportation efficiency of gas transmission pipelines. High strength line pipes have been developed to cope with high-pressure operation. Strength in circumferential direction on line pipe is the prime target to hold high pressure safely. In terms of pipe size, pipe diameter has been increased to lead larger D/t. Both of higher strength and larger D/t result in less favorable to deformability of pipeline. To apply strain based design to pipeline, the evaluation of strain capacity, which is related to deformability of line pipe, is required supposing the pipeline encounters large scale ground movement such as earthquake or landslide. It is not simple to find the criteria to prevent leak or rupture of pipeline in such events, as not only pipe property but also interaction between pipe and soil are needed to consider. Gas transmission pipelines are constructed by joint girth welding. The strain capacity of pipeline with girth weld has to be investigated for strain based design. Full scale bending test of joint welded pipe was conducted and FEA model to assess strain capacity of pipeline with girth weld is developed.

Strain Capacity Investigation on Grade X70 High Strain Line Pipe With Girth Weld

2018 ◽  
Author(s):  
Hisakazu Tajika ◽  
Takahiro Sakimoto ◽  
Tsunehisa Handa ◽  
Satoshi Igi ◽  
Rinsei Ikeda ◽  
...  
Keyword(s):  
High Strain ◽  
Compressive Strain ◽  
Bending Test ◽  
High Grade ◽  
Line Pipe ◽  
Strain Capacity ◽  
Global Strain ◽  
Significant Difference ◽  
Pipeline Project ◽  
Pipe Bending

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipe with size of 36” OD and 23mm WT was investigated with two types of experiments. One was a pipe bending test with whole pipe. The length of the specimen was approximately 8m and GW was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. The other test was curved wide plate (CWP) test. In both tests, test pipes were cut and welded using GTAW in the first two layers and GMAW for the subsequent passes. Welding wire of TG-S62 and MG-S58P were used for GTAW and GMAW respectively to achieve over-matching girth weld considering the pipe body strength. Elliptical EDM notch was installed in the GW HAZ as simulated weld defect. In pipe bending test, buckling occurred at the intrados at 300 mm apart from the GW. 2D average compressive strain at buckling was 3.59% and this high compressive strain was considered to derive from the high strain capacity of this pipes. After the buckling, deformation concentrated to the buckling wrinkle. Test pipe broke at 35.5 degrees of pipe end rotation and the location was in base metal at the extrados opposite to the buckling wrinkle. The HAZ notch opened and CTOD was 1.44 mm and the global strain in 2D length average strain was 7.8%. In CWP test, tensile strain simply got large and pipe finally broke at global strain of 9.6% and CTOD of 15 mm. The break location was the HAZ notch. There was a significant difference in CTOD growth in HAZ between two test types. Conditions and factors that effect to these differences are argued in this paper.

A Study of Deformation Behavior of Double Jointing Girth Welds

2012 ◽  
Author(s):  
Tomoyuki Yokota ◽  
Yoshiaki Murakami ◽  
Takahiro Sakimoto ◽  
Igi Satoshi ◽  
Shigeru Endo
Keyword(s):  
Weld Metal ◽  
Weld Joint ◽  
Arc Welding ◽  
Deformation Behavior ◽  
Base Material ◽  
High Strength ◽  
Strain Capacity ◽  
Girth Welds ◽  
Submerged Arc ◽  
Softening Region

Demand for double jointing technology is increasing to improve pipeline construction productivity. Submerged arc welding (SAW) utilized for double jointing is likely to cause a much wider heat affected zone (HAZ) than those of typical field welding by gas metal arc welding (GMAW), and it should be taken into account for strain-based design of high strength line-pipes. However, guidelines for SAW welds properties to ensure strain capacity of high strength line-pipes such as X80 have not been established yet. In this study, a submerged arc weld joint was produced using tensile strength (TS) over-matching welding consumable. API standard type transverse weld tension test was conducted to measure local elongation at weld metal, HAZ, and base material. Elongation at weld metal increases prior to base material, but soon after that elongation at the HAZ softening region and base material adjacent to the HAZ catch up with the elongation in the weld metal, and finally, deformation concentrates at the HAZ softening region before final fracture. Deformation behavior of the joint was analyzed to verify applicability to double jointing girth welds for strain-based design. From finite element (FE) analysis of notched wide plate test which characterizes tensile strain capacity of a pipeline, it is suggested that ductile crack would not initiate before base material start necking in this particular TS over-matching weld joint in which the defect size is 1mm of notch depth and 25mm of notch length. Thus, the weld joint would be applicable for double jointing girth welds based on strain-based design.

Production of Grade X80 High Strain Linepipes for Seismic Region Application

2010 ◽  
Author(s):  
Ryuji Muraoka ◽  
Joe Kondo ◽  
Lingkang Ji ◽  
Hongyuan Chen ◽  
Yaorong Feng ◽  
...  
Keyword(s):  
High Strain ◽  
Uniform Elongation ◽  
High Strength ◽  
Longitudinal Direction ◽  
Full Scale ◽  
Ground Movement ◽  
Long Distance ◽  
Seismic Region ◽  
Strain Capacity ◽  
Pipe Bending

In order to achieve safety and reliability of long-distance gas transmission pipeline installed in seismic region while obtaining economical benefit by reducing material and construction cost, it is essential to apply the high-strength linepipes with sufficient strain capacity against buckling and weld fracture by seismic ground movement. At the same time, it is quite important to develop appropriate material requirement for strain capacity depending on the pipe dimension and strain demand of the region where the pipeline is installed. Grade X80 heavy gauge linepipes with excellent deformability were mass produced by applying advanced plate manufacturing technologies. These linepipes exhibit low Y/T and high uniform elongation in the longitudinal direction even after pipe coating. Strain capacity of the pipe against bending deformation with internal pressure was verified by conducting full scale pipe bending testing. In this paper, production results of high strain X80 linepipes for the application in long-distance pipelines in seismic region and full scale pipe bending and hydraulic burst test results were introduced.

Development of X80M Line Pipe Steel for Spiral Welded Pipes With Low Temperature Toughness and Excellent Weldability

2014 ◽  
Author(s):  
Nuria Sanchez ◽  
Özlem E. Güngör ◽  
Martin Liebeherr ◽  
Nenad Ilić
Keyword(s):  
Low Temperature ◽  
Life Cycle Cost ◽  
Volume Fraction ◽  
Large Diameter ◽  
Pipe Production ◽  
Strain Accumulation ◽  
Long Distance ◽  
Line Pipe ◽  
Low Temperature Toughness ◽  
Welded Pipe

The unique combination of high strength and low temperature toughness on heavy wall thickness coils allows higher operating pressures in large diameter spiral welded pipes and could represent a 10% reduction in life cycle cost on long distance gas pipe lines. One of the current processing routes for these high thickness grades is the thermo-mechanical controlled processing (TMCP) route, which critically depends on the austenite conditioning during hot forming at specific temperature in relation to the aimed metallurgical mechanisms (recrystallization, strain accumulation, phase transformation). Detailed mechanical and microstructural characterization on selected coils and pipes corresponding to the X80M grade in 24 mm thickness reveals that effective grain size and distribution together with the through thickness gradient are key parameters to control in order to ensure the adequate toughness of the material. Studies on the softening behavior revealed that the grain coarsening in the mid-thickness is related to a decrease of strain accumulation during hot rolling. It was also observed a toughness detrimental effect with the increment of the volume fraction of M/A (martensite/retained austenite) in the middle thickness of the coils, related to the cooling practice. Finally, submerged arc weldability for spiral welded pipe manufacturing was evaluated on coil skelp in 24 mm thickness. The investigations revealed the suitability of the material for spiral welded pipe production, preserving the tensile properties and maintaining acceptable toughness values in the heat-affected zone. The present study revealed that the adequate chemical alloying selection and processing control provide enhanced low temperature toughness on pipes with excellent weldability formed from hot rolled coils X80 grade in 24 mm thickness produced at ArcelorMittal Bremen.

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