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.

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

Applicability of SE(T) and SE(B) Fracture Specimens in Crack Growth Measurements of Pipeline Girth Welds

2012 ◽  
Author(s):  
Leonardo L. S. Mathias ◽  
Gustavo H. B. Donato ◽  
Claudio Ruggieri
Keyword(s):  
Crack Growth ◽  
Oil And Gas ◽  
Pipeline Steel ◽  
High Strength ◽  
Oil And Gas Industry ◽  
Crack Growth Resistance ◽  
X80 Pipeline Steel ◽  
Fixed Amount ◽  
Resistance Curves ◽  
Girth Welds

This work presents an investigation of the ductile tearing properties for a girth weld made of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-Δa curves). Use of these materials is motivated by the increasing demand in the number of applications for manufacturing high strength pipes for the oil and gas industry including marine applications and steel catenary risers. Testing of the pipeline girth welds utilized side-grooved, clamped SE(T) specimens and 3P bend SE(B) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using a single specimen technique. The shallow-crack SE(B) specimen provides an R-curve which, albeit slightly more conservative, exhibits levels of J-values which are relatively comparable to the levels of J corresponding to the deeply-cracked SE(T) specimen at a fixed amount of crack growth, Δa. This experimental characterization provides additional toughness data which serve to evaluate crack growth resistance properties of pipeline girth welds using SE(T) and SE(B) specimens with weld centerline cracks.

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.

The Effects of Constraint and Compressive or Tensile Residual Stresses on Brittle Fracture

2009 ◽  
Author(s):  
Simon Kamel ◽  
Robert C. Wimpory ◽  
Michael Hofmann
Keyword(s):  
Fracture Toughness ◽  
Residual Stress ◽  
Brittle Fracture ◽  
Driving Force ◽  
High Strength ◽  
Element Analysis ◽  
Crack Driving Force ◽  
Temperature Fracture ◽  
Crack Tip Constraint ◽  
Two Parameter

Residual stress is a key feature in components containing defects which can affect the crack driving force and alter the crack tip constraint to give a modified fracture toughness. In this paper experimental and numerical investigations are performed on ‘C’ shape fracture mechanics specimens, extracted from a high strength low alloy tubing steel, to examine the effects of constraint and tensile or compressive residual stress on brittle fracture. The residual stress is introduced into the specimens by a tensile or compressive mechanical pre-load to produce, respectively, a compressive or tensile residual stress in the region where the crack is introduced. Neutron diffraction measurements are performed on the pre-loaded specimens prior to introduction of a crack, and compared with predictions of the residual stress from finite-element analysis, using tensile properties derived at room temperature. Fracture toughness tests are carried out on the as-received (non-preloaded) and pre-loaded specimens and the effect of residual stress on crack driving force and constraint is evaluated using the two-parameter J-Q approach.

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.

scholarly journals Finite Element Analysis of Hollow Beams Strengthed With Frp Wrapping

2019 ◽  
Vol 8 (6) ◽  
pp. 690-694
Keyword(s):  
Numerical Models ◽  
High Strength ◽  
Absorption Capacity ◽  
Hollow Core ◽  
Element Analysis ◽  
Structural Applications ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Hollow Beams ◽  
Cfrp Wrapping

In recent years, the structural applications of hollow core beams became widespread because of its advantages such as high strength, large energy absorption capacity, light weight, adequate ductility and concrete saving. The main objective of this study is to analyse the performance of reinforced hollow core beams strengthened with CFRP (Carbon Fibre Reinforced Polymer) wrapping. Experimental results revealed that the confinement of CFRP wrapping significantly enhanced the load carrying capacity, stiffness of hollow core beams. Numerical models were developed with the help of ANSYS software to validate the behaviour of hollow beams with CFRP wrapping.

Finite Element Analysis on the Application of Mini-C(T) Test Specimens for Fracture Toughness Evaluation

2015 ◽  
Author(s):  
Hisashi Takamizawa ◽  
Tohru Tobita ◽  
Takuyo Ohtsu ◽  
Jinya Katsuyama ◽  
Yutaka Nishiyama ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Zone ◽  
Compact Tension ◽  
Distribution Analysis ◽  
Constraint Effect ◽  
Element Analysis ◽  
Toughness Evaluation ◽  
Fracture Toughness Evaluation

Fracture toughness evaluation by the Master Curve method using 4-mm-thick miniature compact tension (mini-C(T)) specimens taken from the broken halves of surveillance Charpy specimens has been proposed. In the present study, we performed finite element analysis (FEA) to examine the difference in the constraint effect of the crack tip for differently sized C(T) and precracked Charpy v-notch specimens. The constraint effect of the mini-C(T) specimens in terms of the T-stress and Q-parameter was similar to that of the larger C(T) specimens. In addition, to optimize the fatigue precracking conditions for the mini-C(T) specimen, plastic zone distribution analysis was performed by FEA. Using plastic zone distribution analysis, we demonstrated that a wider machined notch and shorter fatigue precrack length than that in conventional configurations can be applied for narrow and straight notches. We also obtained the fracture toughness data for two kinds of SA533B-1 steels and one weld metal with different sizes in addition to the data obtained in our previous study. It was shown that the reference temperature To obtained from the mini-C(T) specimens was in good agreement with those from other specimens. We compared the fracture toughness data, including the plane strain fracture toughness value obtained by 4T-C(T) specimens, with T41J-based fracture toughness curves proposed in a recent study. Most of the data, including the 4T-C(T) and irradiated specimens, were enveloped by the proposed lower-bound curve.

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 Evaluation for Welded Joints of High Strength Steel Through CTOD Test

2010 ◽  
Author(s):  
Jin Gan ◽  
Qiming Yu ◽  
Weiguo Wu ◽  
Jingxia Le
Keyword(s):  
Fracture Toughness ◽  
Test Temperature ◽  
Welded Joints ◽  
High Strength Steel ◽  
Steel Plate ◽  
High Strength ◽  
Bending Tests ◽  
Toughness Evaluation ◽  
Open Displacement ◽  
Fracture Toughness Evaluation

This paper presents the method and procedure of CTOD test which are used for the toughness evaluation for welded joints. Two types of high strength steel (E38 and E43) are chosen as the object of fracture toughness evaluation. The contents of CTOD test include three-point crack tip open displacement (CTOD) bending tests for base metal (BM) specimens, weld position (WP) specimens and heat-affected zone (HAZ) specimens of the high strength steel, considering different thickness of steel plate and different test temperature (−20°C and 20°C). The CTOD test can achieve the P-V curves of samples, and the CTOD values are calculated. On the basis of the above work, the results of toughness evaluation are obtained. Meanwhile, some factors which affect the toughness of high strength steel are discussed in this paper, such as thickness of steel plate and test temperature, and many valuable conclusions are achieved.

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