Variation of the Fracture Toughness of a High-Strength Pipeline Steel under Cathodic Protection

CORROSION ◽  
2001 ◽  
Vol 57 (8) ◽  
pp. 721-729 ◽  
Author(s):  
P. Andrews ◽  
M. McQueen ◽  
N. Millwood
Keyword(s):  
Fracture Toughness ◽  
Cathodic Protection ◽  
Pipeline Steel ◽  
High Strength

The Effect of Low Sulfur Content on the Weldability of Linepipe Steel

2012 ◽  
Author(s):  
Kimberly K. Cameron ◽  
Alfred M. Pettinger
Keyword(s):  
Fracture Toughness ◽  
Sulfur Content ◽  
Large Scale ◽  
Pipeline Steel ◽  
Active Agent ◽  
High Strength ◽  
Pipeline System ◽  
Line Pipe ◽  
Low Sulfur ◽  
Linepipe Steel

Over time, the demand for high-strength linepipe has increased significantly. One of the challenges for developing higher strength linepipe has been maintaining an appropriate level of fracture toughness, yield to tensile strength ratio, and weldability. Fortunately, significant progress has been made in the production of high strength line pipe steel. A major improvement in steel making has been the utilization of secondary steel treatments to refine the steel and accurately control alloy additions to achieve a higher level of steel cleanliness. In particular, these refining treatments have enabled the achievement of extremely low sulfur levels. For most purposes, restricting sulfur content is desirable to help prevent a reduction in mechanical properties such as fracture toughness of the steel. Fortunately, steelmaking and desulfurization technologies have advanced to the point where pipeline steel with sulfur contents less than the requirements by API 5L are available on a large scale. Extremely low sulfur contents, however, can lead to other problems when welding steels. These weldability problems are related to the fact that sulfur is a known surface active agent for steels. Low sulfur concentrations lead to a reversal of the Marangoni convection in the weld pool, which is responsible for the large differences in weld penetration on otherwise identical steels. Additionally, when welding heats of unmatched sulfur concentrations, the arc will tend to deviate towards the low sulfur heat and axially shift the root of the weld if one of the heats was below a critical value for the sulfur content and the other was above this value. Although this phenomenon has been primarily observed in stainless steels, the increasing ability to produce linepipe steel with extremely low sulfur contents has led to the possibility that this phenomenon could also occur in low carbon pipeline steels. One pipeline system utilizing cellulosic consumables for shielded metal arc welding (SMAW) of X70 steel with sulfur contents an order of magnitude below that permitted by API 5L and with widely varying sulfur contents shows evidence of this effect. The profiles of the welds in this system exhibited a tendency for lack of penetration, asymmetric weld roots, and concave welds. One approach to ameliorate this would be the specification of a lower permissible amount of sulfur.

scholarly journals Stress Triaxial Constraint and Fracture Toughness Properties of X90 Pipeline Steel

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 72
Author(s):  
Peng Wang ◽  
Wenqian Hao ◽  
Jiamiao Xie ◽  
Fang He ◽  
Fenghui Wang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Pipeline Steel ◽  
Numerical Models ◽  
Evaluation Research ◽  
Engineering Application ◽  
High Strength ◽  
Element Analysis ◽  
Toughness Evaluation ◽  
Integral Distribution ◽  
Resistance Curves

The X90 pipeline steel with high-strength and high-toughness become the most popular pipeline steel. Due to the stress triaxial constraint and fracture toughness properties are the key factors for the stable work of pipeline steel, the research on the fracture toughness of X90 is a great significance to promote the engineering application of high-strength pipeline steel. In order to investigate the stress triaxial constraint and fracture toughness properties of X90 pipeline steel, the experimental rules with different grooves size are proposed using the common toughness experiment and the corresponding numerical models are established in this paper. The resistance curves and fracture toughness of each type of specimens are obtained and compared with that of finite element analysis. Furthermore, the stress distribution, J-integral distribution and stress triaxial constraint of the specimen are analyzed, as well as the influence of side grooves size on the determination of fracture toughness is also discussed. The results obtained from the study will provide a reference to the fracture toughness evaluation research and application of X90 pipeline steel.

scholarly journals Investigation of Hydrogen Embrittlement Susceptibility and Fracture Toughness Drop after in situ Hydrogen Cathodic Charging for an X65 Pipeline Steel

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 430 ◽  
Author(s):  
Helen Kyriakopoulou ◽  
Panagiotis Karmiris-Obratański ◽  
Athanasios Tazedakis ◽  
Nikoalos Daniolos ◽  
Efthymios Dourdounis ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
High Strength ◽  
Electrolytic Cell ◽  
Low Alloy Steels ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Alloy Steels

The present research focuses on the investigation of an in situ hydrogen charging effect during Crack Tip Opening Displacement testing (CTOD) on the fracture toughness properties of X65 pipeline steel. This grade of steel belongs to the broader category of High Strength Low Alloy Steels (HSLA), and its microstructure consists of equiaxed ferritic and bainitic grains with a low volume fraction of degenerated pearlite islands. The studied X65 steel specimens were extracted from pipes with 19.15 mm wall thickness. The fracture toughness parameters were determined after imposing the fatigue pre-cracked specimens on air, on a specific electrolytic cell under a slow strain rate bending loading (according to ASTM G147-98, BS7448, and ISO12135 standards). Concerning the results of this study, in the first phase the hydrogen cations’ penetration depth, the diffusion coefficient of molecular and atomic hydrogen, and the surficial density of blisters were determined. Next, the characteristic parameters related to fracture toughness (such as J, KQ, CTODel, CTODpl) were calculated by the aid of the Force-Crack Mouth Open Displacement curves and the relevant analytical equations.

The Analysis for Relation of Fracture Toughness and Charpy Impact Energy of High Strength Pipeline Steel

2008 ◽  
Author(s):  
Guang-Li Zhang ◽  
Xin-Wei Zhao ◽  
Jin-Heng Luo ◽  
Shao-Tao Gong ◽  
Hua Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Impact Energy ◽  
Empirical Equation ◽  
Pipeline Steel ◽  
Linear Regression Analysis ◽  
Charpy Impact ◽  
High Strength ◽  
Charpy Impact Energy ◽  
Sample Data ◽  
New Equation

According to the linear regression analysis, a new empirical equations between the fracture toughness (KIc) and Charpy impact energy (CVN) of X80 high strength pipeline steel, were developed on the basis of experiment sample data. And the theory of statistical test was used to test the significance of the new equation. The test result indicated that the new empirical equation has very high significance with the sample data. Comparing with the empirical equation recommended by the API 579-2007, the empirical equation developed here was more suitable for the X80 high strength pipeline steel, and can make better estimation for the fracture toughness of X80. And for the estimation of fracture toughness of X100 high strength pipeline steel, the equation developed here is applicable too.

Fracture Toughness Testing of Pipeline Girth Welds

2004 ◽  
Author(s):  
G. Shen ◽  
J. A. Gianetto ◽  
R. Bouchard ◽  
J. T. Bowker ◽  
W. R. Tyson
Keyword(s):  
Fracture Toughness ◽  
Pipeline Steel ◽  
High Strength ◽  
X80 Pipeline Steel ◽  
Factors Affecting ◽  
Fracture Toughness Testing ◽  
Toughness Testing ◽  
Girth Welds ◽  
Guidelines And Recommendations ◽  
Testing Standards

The guidelines and recommendations for fracture toughness testing of pipeline girth welds outlined in CSA Z662-03, Annex K are reviewed in this work. In Annex K of CSA Z662-03, the specimen type and notch location have been grouped into four categories and the CTOD tests are to be carried out in accordance with either BSI Standard 7448 or ASTM Standard E 1290. In the present study, CTOD tests have been conducted on a manual shielded-metal-arc weld (SMAW) that was prepared in a high strength X80 pipeline steel. The experimental results obtained by applying the two testing standards are compared. The focus was to identify the differences between these two standards that may significantly affect the test results, such as the requirements for straightness of the fatigue crack, and the equations and parameters used for evaluation of CTOD. Some additional factors affecting the testing, such as selection of test specimen location and procedures for targeting specific weldment microstructures as well as the application of local compression, are also discussed. The variation of strength and toughness with clock position around the circumference of the girth welds has also been studied.

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

Phase separation in sol gel-derived ceramic films of silica-zirconia, alumina-zirconia, and titania-zirconia system

1994 ◽  
Vol 52 ◽  
pp. 646-647
Author(s):  
J. Tong ◽  
L. Eyring
Keyword(s):  
Fracture Toughness ◽  
Phase Separation ◽  
Sol Gel ◽  
Great Influence ◽  
High Strength ◽  
Chemical Durability ◽  
Separation Method ◽  
Toughening Mechanism ◽  
Ceramic Films ◽  
Zirconia Toughened Alumina

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.

Effect of thickness on the fracture toughness of high strength steel for gas well casings

2018 ◽  
Vol 60 (11) ◽  
pp. 1077-1083 ◽  
Author(s):  
Zhaoming Zhou ◽  
Xishui Guo ◽  
Tiejun Lin ◽  
Desen Mao
Keyword(s):  
Fracture Toughness ◽  
High Strength Steel ◽  
High Strength ◽  
Gas Well

CARLSON ALLOY C600 and C600 ESR

Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Cold Working ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Solid Solution Alloy ◽  
Resistance To Oxidation ◽  
Good Workability

Abstract CARLSON ALLOYS C600 AND C600 ESR have excellent mechanical properties from sub-zero to elevated temperatures with excellent resistance to oxidation at high temperatures. It is a solid-solution alloy that can be hardened only by cold working. High strength at temperature is combined with good workability. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Ni-470. Producer or source: G.O. Carlson Inc.

INCONEL ALLOY 725

Alloy Digest ◽  
1994 ◽  
Vol 43 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Inconel Alloy ◽  
Alloy 625

Abstract INCONEL ALLOY 725 is an age-hardenable alloy that displays high strength along with excellent ductility and toughness. Its corrosion resistance is comparable to alloy 625. Good flattening properties are exhibited in age-hardened tubing. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating and machining. Filing Code: Ni-445. Producer or source: Inco Alloys International Inc.

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