Effects of Aging on the Mechanical Properties of Pipeline Steels

2008 ◽  
Author(s):  
Martin Hukle ◽  
Brian Newbury ◽  
Dan Lillig ◽  
Jonathan Regina ◽  
Agnes Marie Horn
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Uniform Elongation ◽  
Weld Line ◽  
Base Material ◽  
Pipeline System ◽  
Line Pipe ◽  
Pipeline Steels ◽  
Reduction Of Area ◽  
Effects Of Aging

The intelligent design of a given pipeline system intended for operation beyond the elastic limit should incorporate specific features into both the base material (line pipe) and girth weld that enable the affected system to deform safely into the plastic regime within the intended strain demand limits. The current paper focuses on the mechanical properties known to influence the strain capacity of the base material (i.e., line pipe steel independent of the girth weld). Line pipe mechanical properties of interest include: longitudinal yield strength, tensile strength, yield to tensile strength ratio, reduction of area, elongation and uniform elongation. Of particular interest (in consideration of the conventional thermally applied corrosion protection coating systems to be employed), are the longitudinal mechanical properties in the “aged” condition. The present study investigates six (6) different pipeline steels encompassing grades X60 (415 MPa) to X100 (690 MPa), and includes both UOE Submerged Arc Welded - Longitudinal (SAW-L) and seamless (SMLS) forming methods.

A Case Study in High Strain Capacity Pipeline Qualification: PNG LNG Project

2014 ◽  
Author(s):  
Fredrick F. Noecker ◽  
Doug Fairchild ◽  
Mike Cook ◽  
Mario Macia ◽  
Wan Kan
Keyword(s):  
Tensile Strength ◽  
Uniform Elongation ◽  
Active Faults ◽  
Lessons Learned ◽  
Analytical Models ◽  
Weld Strength ◽  
Pipeline System ◽  
Line Pipe ◽  
Strain Capacity ◽  
Girth Welds

The onshore pipeline portion of the Papua New Guinea Liquefied Natural Gas (PNG LNG) project traverses terrain with seismically active faults with potential ground displacements up to four meters. The resulting longitudinal strain demand exceeds 0.5% strain, thereby requiring use of strain-based pipeline design (SBD) technology. This paper discusses the application of previously developed strain-based design methodologies to successfully qualify the PNG LNG pipeline system for a design tensile strain demand up to 3%, and flexibility to increase the design strain demand with additional restrictions on key variables impacting strain capacity at select locations. Key SBD pipeline qualification activities are discussed along with the required project timeline. The first activity is specifying, evaluating and procuring line pipe suitable for strain-based design. SBD line pipe must be strain-age resistant, have excellent longitudinal uniform elongation, and have tightly controlled ultimate tensile strength (UTS) limits to ensure robust girth weld overmatch. The girth welds must exhibit upper shelf fracture toughness, excellent tearing resistance, and have sufficient tensile strength to ensure adequate girth weld strength overmatch. The pipeline qualification effort culminates in full scale pipe strain testing as proof of performance. The specimens for these tests are fabricated with project-specific pipe, girth welds, and pipe fit-up (hi-lo misalignment). The girth welds contain machined flaws in both weld metals and heat affected zones, these flaws being sized consistent with acceptable flaw sizes predicted from analytical models and prior experience. The results of these tests and their significance are described. Efforts to reduce capacity through lowering strain demand are outlined, along with examples of construction challenges the project has successfully faced. Key engineering and project decisions, and lessons learned from this qualification effort are also detailed.

Effect of Weld Line Formation on Morphology and Mechanical Properties for 3D-MID Technology

2015 ◽  
Vol 659 ◽  
pp. 659-665
Author(s):  
Supakit Chuaping ◽  
Thomas Mann ◽  
Rapeephun Dangtungee ◽  
Suchart Siengchin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Injection Molding ◽  
Filler Content ◽  
Research Work ◽  
Weld Line ◽  
Processing Conditions ◽  
High Reduction ◽  
Flexural Tests

The topic of this research work was to demonstrate the feasibility of a 3D-MID concept using injection molding technique and investigate the effects of two weld line types on the structure and mechanical properties such as tensile, flexural strength and morphology. In order to obtain more understanding of the bonds between polymer and metals, two different polymer bases of polyphthalamide (PPA) with the same type and amount of filler content were produced by injection molding at the different processing conditions. A mold was designed in such a way that weld and meld line can be produced with different angles by changing as insert inside of the mold. The mechanical properties such as stiffness, tensile strength and flexural strength were determined in tensile and flexural tests, respectively. The results showed in line with the expectation of high reduction on mechanical properties in area where weld/meld lines occurred. The result of tensile test was clearly seen that weld and meld line showed a considerable influence on mechanical properties. The reduction in tensile strength was approximately 58% according to weld line types, whereas in flexural strength was approximately 62%. On the other hand, the effect of the injection times and mold temperatures on the tensile strength were marginal.

Effects of RE on Inclusions and Mechanical Properties of Weathering Steel

2012 ◽  
Vol 204-208 ◽  
pp. 3843-3846
Author(s):  
Xiao Liu ◽  
Hu Fei Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Ductile Fracture ◽  
Weathering Steel ◽  
Transverse Impact ◽  
Reduction Of Area

The effects of RE on the inclusions and the mechanical properties of 10PCuRE steel were studied. The results show that the morphologies and sizes of inclusions in 10PCuRE steel are changed, and RE played a very good role of modifying inclusions. Fracture is changed from cleavage to ductile fracture by adding RE to 10PCuRE steel. And the mechanical properties of 10PCuRE are improved. In comparison with 10PCuRE steel without RE, the transverse impact toughness of 10PCuRE steel with RE is increased 30.15% at -20°C, and the tensile strength and reduction of area have been improved 27.14%, 8.9%, respectively.

scholarly journals A Study on Fiber Laser Welding of High-Manganese Steel for Cryogenic Tanks

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1536
Author(s):  
Jaewoong Kim ◽  
Jisun Kim ◽  
Changmin Pyo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Laser Welding ◽  
Base Material ◽  
Manganese Steel ◽  
High Manganese ◽  
Fiber Laser Welding ◽  
High Manganese Steel ◽  
Welding Part

As the environmental regulations on ship emissions by the International Maritime Organization (IMO) become stricter, the demand for a ship powered by liquefied natural gas (LNG) is rapidly increasing worldwide. Compared to other materials, high-manganese steel has the advantages of superior impact toughness at cryogenic temperatures, a low thermal expansion coefficient, and a low-cost base material and welding rod. However, there is a limitation that the mechanical properties of a filler material are worse than those of a base material that has excellent mechanical properties. To solve these shortcomings, a basic study was performed to apply fiber laser welding with little welding deformation and no filler material to high-manganese steel. The relationship between laser welding parameters and penetration shapes was confirmed through cross-section observation and analysis by performing a bead on plate (BOP) test by changing laser power and welding speed, which are the main parameters of laser welding. In addition, the welding performance was evaluated through mechanical property tests (yield strength, tensile strength, hardness, cryogenic impact strength) of a welding part after performing the high-manganese steel laser butt welding experiment. As a result, it was confirmed that the yield strength of a high-manganese steel laser welding part was 97.5% of that of a base metal, and its tensile strength was 93.5% of that of a base metal.

Experimental Research on Mechanical Properties of Polypropylene Flexible Intermediate Bulk Container Base Materials

2013 ◽  
Vol 811 ◽  
pp. 146-151
Author(s):  
Chen Wei Chen ◽  
Fu Xin Yang ◽  
Li Xin Lu ◽  
Jin Xie ◽  
Li Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Low Temperature ◽  
Base Material ◽  
Powder Materials ◽  
Base Materials ◽  
Natural Exposure ◽  
Exposure Experiment ◽  
Tensile Experiment

The Flexible Intermediate Bulk Container (FIBC) is a flexible transportation packaging container that is weaved by polyolefin plastic ribbon-like filament, which is widely used in the storage and transportation of granular and powder materials. When the FIBC was affected by environment factors synthetically under using, such as light, heat and air etc, it would come into degradation and its mechanical properties reduced. In this study, the basic mechanical properties of polypropylene FIBC base material were tested by tensile experiment and the reason of main base material mechanical properties difference between theoretical value and experimental value was analyzed. Based on the FIBC different using environments, the natural exposure experiment and high/low temperature experiments were carried out, we took tensile strength holding ratio and elongation holding ratio as evaluating indicator and analyzed law of influence of the different experiment condition on base material mechanical properties, which provided valuable reference for FIBC designing and manufacturing. Along with the experiment time increased, the color of base material changed from milk white to yellow slowly, the tensile strength and elongation reduced, the influencing grade was as follow: natural exposure>high temperature>low temperature. The results of natural exposure experiment showed that there was difference of anti-aging performance among the FIBC base material, the mechanical properties of woof fabric and belt reduced evidently, while others reduced slowly. For high (45°C)/low (-25°C) temperature experiments, the reduction of FIBC base materials mechanical properties were not obvious and woof fabric reduced a little faster comparatively.

An investigation on the mechanical properties of friction stir welded polycarbonate/aluminium oxide nanocomposite sheets

2016 ◽  
Vol 49 (6) ◽  
pp. 498-512 ◽  
Author(s):  
Ali Doniavi ◽  
Saeedeh Babazadeh ◽  
Taher Azdast ◽  
Rezgar Hasanzadeh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Rotational Speed ◽  
Signal To Noise Ratio ◽  
Base Material ◽  
Travel Speed ◽  
Effective Parameter ◽  
Welding Parameters ◽  
Effective Parameters ◽  
Friction Stir

Although considerable progress has been made in recent years in field of polymer welding, challenges still remain in using a friction stir welding method to join polycarbonate (PC) composites. This research provides an investigation on the effect of welding parameters (tool’s travel and rotational speeds) on mechanical properties of PC nanocomposite weld lines. PC nanocomposites were prepared with different percentages of Al2O3 nanofiller using a twin screw extruder and injection moulded as sheets in order to ease the welding. Considering various parameters and their levels, optimization of Taguchi experimental design was carried out, an L16 orthogonal standard array was selected and the effective parameter was calculated using analysis of variance of the results. The results indicated that nanoalumina percentage is the most effective parameter on the tensile strength of weld and tool’s travel speed and rotational speed are next effective parameters, respectively. According to signal-to-noise ratio, maximum weld tensile strength (89.5% of base material) is revealed when nanoalumina percentage, tool’s travel speed and tool’s rotational speed were chosen as 1 wt%, 12 mm/min and 1250 r/min, respectively.

Change of Mechanical Properties of High Strength Line Pipe by Thermal Coating Treatment

2005 ◽  
Author(s):  
Yasuhiro Shinohara ◽  
Takuya Hara ◽  
Eiji Tsuru ◽  
Hitoshi Asahi ◽  
Yoshio Terada ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Uniform Elongation ◽  
High Strength ◽  
Secondary Phase ◽  
Longitudinal Direction ◽  
Dual Phase ◽  
Line Pipe ◽  
Thermal Coating ◽  
Production Conditions

In strain-based design, the overmatch condition in the girth weld portion primarily must be maintained. The pipes may also be required to have a low yield to tensile (Y/T) ratio and a high uniform elongation (U.EL) in the longitudinal direction to achieve a high compressive buckling strain. However, change in the mechanical properties by heating during coating treatment has not been paid attention so much. Furthermore, how much the mechanical properties change is affected by production conditions is unclear. This study aims to clarify firstly the relation between the mechanical properties (Y/T ratio, U.EL etc.) and the microstructure and secondly the change in mechanical properties by thermal coating treatment. The Y/T ratio and U.EL are affected by the volume fraction of ferrite and the secondary phase, which are changed by thermomechanical control processing (TMCP) conditions. For example, use of dual phase microstructure is very effective for decreasing the Y/T ratio and increasing the U.EL as the pipe. On the other hand, yield strength (YS) rises and the U.EL does not change after coating. The increase in the YS after coating is influenced by the microstructure and TMCP conditions. Resultantly, dependence of the Y/T ratio on the microstructure and TMCP conditions is reduced for line pipes after thermal coating treatment.

A method to improve dimensional accuracy and mechanical properties of injection molded polypropylene parts

2017 ◽  
Vol 37 (4) ◽  
pp. 323-334 ◽  
Author(s):  
Shuai Li ◽  
Guoqun Zhao ◽  
Jiachang Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Injection Molding ◽  
Weld Line ◽  
Dimensional Accuracy ◽  
Holding Time ◽  
Dimensional Shrinkage ◽  
Injection Molded ◽  
The Impact

Abstract Gas counter pressure (GCP) technology can impose a reverse pressure to melt and thereby effectively increase the pressure acting on the melt at flow front. Theoretically, it has a potential to solve some defects often occurring in conventional injection molding (CIM) process. This paper designed and manufactured a GCP injection mold. GCP injection molding experiments were conducted. Effects of GCP process on melt flow and density, dimensional accuracy, and mechanical properties of molded samples were investigated. The results showed that GCP process can effectively inhibit the “fountain effect” in melt filling process, decrease the dimensional shrinkage of molded samples, increase dimensional accuracy of samples, and effectively improve impact property of samples. For the samples without weld line, tensile strength and flexural strength of GCP injection molded samples are slightly increased in comparison with those of CIM samples, but for the samples with weld line, GCP process can greatly improve the tensile strength and flexural strength of molded samples. When GCP is 9 MPa and GCP holding time is 10 s, the dimensional accuracy of molded samples without weld line, the tensile strength and flexural strength of the molded samples with weld line all increase up to maximum values. In comparison with CIM samples, the dimensional shrinkage of samples without weld line decreases by 17.2%, the tensile strength and flexural strength of samples with weld line increase by 30.51% and 23.69%, respectively. The impact value of the samples molded by process parameter combination of GCP 9 MPa and GCP holding time 20 s is the highest, and the impact value increases by 18.65%.

scholarly journals Laser Oscillating Welding of TC31 High-Temperature Titanium Alloy

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1185
Author(s):  
Zhimin Wang ◽  
Lulu Sun ◽  
Wenchao Ke ◽  
Zhi Zeng ◽  
Wei Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
High Temperature ◽  
Laser Welding ◽  
Room Temperature ◽  
Base Material ◽  
Aerospace Applications ◽  
Weld Appearance ◽  
Laser Welds

The joining of high-temperature titanium alloy is attracting much attention in aerospace applications. However, the defects are easily formed during laser welding of titanium alloys, which weakens the joint mechanical properties. In this work, laser oscillating welding was applied to join TC31 high-temperature titanium alloy. The weld appearance, microstructure and mechanical properties of the laser welds were investigated. The results show that sound joints were formed by using laser oscillating welding method, and a large amount of martensite was presented in the welds. High mechanical properties were achieved, which was approaching to (or even equaled) the strength of the base material. The joints exhibited a tensile strength of up to 1200 ± 10 MPa at room temperature and 638 ± 6 MPa at 923 K. Laser oscillating welding is beneficial to the repression of porosity for welding high-temperature titanium alloy.

scholarly journals Effect of Adding of Green Betel Leaf Extract and Honey on Mechanical Properties of Chitosan/PVA Hydrogel Wound Plaster

2021 ◽  
Vol 2110 (1) ◽  
pp. 012013
Author(s):  
N L F Chamidah ◽  
A B Rahanti ◽  
M D Kadasih ◽  
F D Sharfina ◽  
L Rohmawati
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Leaf Extract ◽  
Base Material ◽  
New Materials ◽  
Betel Leaf ◽  
Second Stage ◽  
Extract Concentration ◽  
Two Stages ◽  
Pva Hydrogel

Abstract Wound plasters on the market still have drawbacks, including lack of elasticity and stinging. Thus, there is a need for new materials from nature to be used as the base material for wound plasters, namely betel leaf extract and honey composited with PVA/chitosan. This study purpose to find out mechanical properties of wound plaster of chitosan/PVA with the composition of betel leaf extract and honey. The first stage is making hydrogel by mixing PVA and chitosan, and the second stage is extracting green betel leaves and honey by the maceration method. Then the two stages were mixed with a composition of 5wt%, 15wt%, and 25wt% green betel leaf extract. The results were tested for tensile strength to determine the elasticity properties of the wound plaster. In this study, the 25wt% betel leaf extract concentration had the best tensile strength value of 0.219 MPa, and the modulus of elasticity was 0.11 MPa.

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