Crystallographic Texture as a Factor Enabling Ductile Fracture Arrest in High Strength Pipeline Steel

2011 ◽  
Vol 702-703 ◽  
pp. 770-773 ◽  
Author(s):  
Igor Pyshmintsev ◽  
Alexey Gervasyev ◽  
Roumen H. Petrov ◽  
Victor Carretero Olalla ◽  
Leo Kestens
Keyword(s):  
Pipeline Steel ◽  
High Strength ◽  
Rolling Plane ◽  
Steel Plates ◽  
Clear Correlation ◽  
Ductile Crack ◽  
Surface Separation ◽  
X80 Steel ◽  
Oriented Parallel ◽  
Fracture Arrest

Low ductile crack arrestability in a full-scale burst test of 1420 mm-diameter X80 steel line pipes was accompanied by a high intensity of fracture surface separation. The texture of the steel plates was studied using different techniques in order to evaluate the influence of {001} planes oriented parallel to the rolling plane on the separation intensity during fracture. Though no clear correlation between the content of {001} planes parallel to the rolling plane and intensity of separation was found, the local distribution of the {001}<110> texture component among the microstructure components was different in different steels providing long areas suitable for cleavage fracture parallel to the rolling plane in steel with low arrestability.

Mechanical and Metallurgical Aspects of the Resistance to Ductile Fracture Propagation in the New Generation of Gas Pipelines

2014 ◽  
Author(s):  
Igor Pyshmintsev ◽  
Alexey Gervasyev ◽  
Victor Carretero Olalla ◽  
Roumen Petrov ◽  
Andrey Arabey
Keyword(s):  
Ductile Fracture ◽  
Mechanical Test ◽  
Fracture Propagation ◽  
Rolling Plane ◽  
Full Scale ◽  
Charpy Test ◽  
Line Pipe ◽  
Surface Separation ◽  
Fracture Arrest ◽  
New Generation

The microstructure and fracture behavior of the base metal of different X80 steel line pipe lots from several pipeline projects were analyzed. The resistance of the pipes to ductile fracture propagation was determined by the full-scale burst tests. The high intensity of fracture surface separation (secondary brittle cracks parallel to the rolling plane of the plate) appeared to be the main factor reducing the specific fracture energy of ductile crack propagation. A method for quantitative analysis of microstructure allowing estimation of the steel’s tendency to form separations is proposed. The procedure is based on the EBSD data processing and results in Cleavage Morphology Clustering (CMC) parameter evaluation which correlates with full-scale and laboratory mechanical test results. Two special laboratory mechanical test types utilizing SENT and Charpy test concepts for prediction of ductile fracture arrest/propagation in a pipe were developed and included into Gazprom specifications.

A Failure Assessment Procedure for Cracked Pipelines Incorporating a Damage Criterion for Crack Growth

2004 ◽  
Author(s):  
Fernando Dotta ◽  
Eduardo Hippert ◽  
Claudio Ruggieri
Keyword(s):  
Crack Growth ◽  
Crack Extension ◽  
Cell Model ◽  
Pipeline Steel ◽  
Longitudinal Crack ◽  
High Strength ◽  
Experimental Program ◽  
Assessment Procedure ◽  
Ductile Crack ◽  
Computational Cell

This study extends a micromechanics approach based upon the computational cell methodology to model ductile crack extension of longitudinal crack-like defects in a high strength pipeline steel. Laboratory testing of an API 5L X60 AND x70 pipeline steel at room temperature using standard, deep crack C(T) specimens provide the data needed to measure the crack growth resistance curve for the material. In the computational cell model, ductile crack extension occurs through void growth and coalescence (by cell extinction) within a thin layer of material ahead of crack tip. A simple scheme to calibrate material-specific parameters for the cells is also described. A central focus of the paper is the application of the cell methodology to predict experimentally measured burst pressures for pre-cracked pipe specimens with different crack sizes. The experimental program includes longitudinally precracked pipe specimens with 8 5/8” (209 mm) and 20” (508 mm) O.D. The numerical simulations demonstrate the effectiveness of the cell approach to describe crack growth response and to predict the burst pressure for the tested pipes.

Enhancing the Toughness of Heavy Thick X80 Pipeline Steel Plates by Microstructure Control

2011 ◽  
Vol 194-196 ◽  
pp. 1183-1191 ◽  
Author(s):  
Wen Jin Nie ◽  
Wei Feng Xin ◽  
Tian Ming Xu ◽  
Pei Jian Shi ◽  
Xiao Bing Zhang
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Pipeline Steel ◽  
Base Material ◽  
Steel Plates ◽  
Microstructure Control ◽  
X80 Pipeline Steel ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
X80 Steel

The experiment results show that the microstructure control plays a key role for enhancing toughness of heavy thick X80 plates at low temperature, especially DWTT property. The toughness of heavy thick X80 plate at low temperature is not only related to the bainite grains and M/A islands, but also impacted by the original austenite grain size. Finer original austenite grain size benefits to increase the BF/AF ratio in volume of a base material enlarge the crystal orientation difference of microstructure transformation inside austenite. Cracks on a broken section of DWTT samples can (a) penetrate the coarse grains directly, (b) propagate in Zig-Zaga way in the fine grains, and (c) be around the boundary of original austenite grains. The stable and high toughness of heavy thick X80 steel plates from the mass production can be achieved at low temperature made with the reasonable chemistry, clean steel, non-defect slab technologies and OHTP rolling practice.

Modified Two-Curve Model for Predicting Fracture Arrest Toughness and Arrest Distance of Full-Size Burst Tests

2016 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Test Data ◽  
Pipeline Steel ◽  
Large Diameter ◽  
High Strength ◽  
Full Scale ◽  
Burst Test ◽  
Pipe Segment ◽  
Single Pipe ◽  
Fracture Arrest ◽  
Arrest Toughness

Running fracture control is a very important technology for gas transmission pipelines with large diameter and high pressure. The Battelle two-curve (BTC) model developed in the early 1970s has been widely used in pipeline industry to determine arrest toughness in terms of the Charpy energy. Because of its semi-empirical nature and calibration with test data only for grades up to X65, the BTC does not work for higher grades. Simple corrections were thus proposed to extend the BTC model to higher grades, but limited to those grades considered. Moreover, the BTC model only predicts the minimum arrest toughness, but not arrest distance. To fill the technical gaps, this paper proposes a modified two-curve (MTC) model and a fracture arrest distance model in reference to the Charpy energy. The MTC model coupling with an arrest distance algorithm can predict fracture arrest toughness and arrest distance in one simulation of numerical integration for a single pipe or a set of multiple pipes with given toughness. Two sets of full-scale burst test data for X70 and X80 are used to validate the proposed model, and the results show good agreements between the predictions and full-scale test data of arrest toughness and arrest distance as well. The MTC model is then applied to optimize a design of pipe segment arrangements for a mockup full-scale burst test on a high-strength pipeline steel. The MTC simulation results confirm the experimental observation that different pipe arrangements determine different arrest toughness and arrest distance for the same grade pipes.

Microstructure and Properties of Pipeline Steel with Acicular Ferrite

2007 ◽  
Vol 539-543 ◽  
pp. 4750-4755
Author(s):  
Lei Zheng ◽  
Shan Gao
Keyword(s):  
Electron Microscopy ◽  
Acicular Ferrite ◽  
Pipeline Steel ◽  
Steel Strip ◽  
Charpy Impact ◽  
High Strength ◽  
Charpy Impact Test ◽  
Low Carbon ◽  
High Fracture ◽  
Fracture Arrest

The X70 grade and X80 grade pipeline steel strip with acicular ferrite microstructure have been researched and developed. The properties of the steel with acicular ferrite were studied by using tensile test, Charpy impact test, CTOD test and DWTT test, and compared to that of the steel with ferrite and pearlite. The microstructure of acicular ferrite was analyzed by using optical metallographic microscopy, scanning electron microscopy and transmission electron microscopy. It shows that the acicular ferrite pipeline steel has high strength, high toughness, low ductile-brittle transition temperature and high fracture-arrest toughness, the excellent properties are benefit from the uniform microstructure, clean steel, and the low carbon acicular ferrite in which consist of interaction of very fine precipitated particles and high-density dislocation.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

Experimental investigation on dissimilar weld between super duplex stainless steel 2507 and API X70 pipeline steel

2021 ◽  
pp. 146442072110130
Author(s):  
Waris N Khan ◽  
Rahul Chhibber
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pipeline Steel ◽  
High Strength ◽  
Super Duplex Stainless Steel ◽  
Shielded Metal Arc Welding ◽  
Electrode Coating ◽  
Dissimilar Weld ◽  
Metal Arc Welding ◽  
Welding Electrode

This work investigates the microstructure and mechanical properties of 2507 super duplex stainless steel and API X70 high strength low alloy steel weld joint. This joint finds application in offshore hydrocarbon drilling riser and oil–gas pipelines. Coated shielded metal arc welding electrodes have been designed and extruded on 309L filler and their performance compared with a commercial austenitic electrode E309L. Filler 309L solidifies in ferrite-austenite (F-A) mode with a resultant microstructure comprising skeletal ferrites with austenite distributed in the interdendritic region. Results of tensile and impact tests indicate that weld fabricated with laboratory-developed electrodes has higher ductility and impact energy than the commercial electrode. The tensile strength and weld hardness of commercial electrodes are superior. The laboratory-made electrode’s microhardness is lower than the commercial electrodes, making the former less prone to failure. An alternative welding electrode coating composition has been suggested through this work and found to be performing satisfactorily and comparable to the commercially available electrodes.

A Micromechanics Approach to Assess Ductile Crack Initiation in Damaged Pipelines

2003 ◽  
Author(s):  
Claudio Ruggieri ◽  
Fernando F. Santos ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Ductile Fracture ◽  
Large Scale ◽  
Cell Model ◽  
High Strength ◽  
Void Coalescence ◽  
Model Parameters ◽  
Ductile Crack ◽  
Cracking Behavior ◽  
Damage Criterion ◽  
Limited Applicability

This study explores the capabilities of a computational cell framework into a 3-D setting to model ductile fracture behavior in tensile specimens and damaged pipelines. The cell methodology provides a convenient approach for ductile crack extension suitable for large scale numerical analyses which includes a damage criterion and a microstructural length scale over which damage occurs. Laboratory testing of a high strength structural steel provides the experimental stress-strain data for round bar and circumferentially notched tensile specimens to calibrate the cell model parameters for the material. The present work applies the cell methodology using two damage criterion to describe ductile fracture in tensile specimens: (1) the Gurson-Tvergaard (GT) constitutive model for the softening of material and (2) the stress-modified, critical strain (SMCS) criterion for void coalescence. These damage criteria are then applied to predict ductile cracking for a pipe specimen tested under cycling bend loading. While the methodology still appears to have limited applicability to predict ductile cracking behavior in pipe specimens, the cell model predictions of the ductile response for the tensile specimens show good agreemeent with experimental measurements.

Mechanical Behaviour of Welded Joints Achieved by Multi-Wire Submerged Arc Welding

2017 ◽  
Vol 1143 ◽  
pp. 52-57
Author(s):  
Elena Scutelnicu ◽  
Carmen Catalina Rusu ◽  
Bogdan Georgescu ◽  
Octavian Mircea ◽  
Melat Bormambet
Keyword(s):  
Mechanical Behaviour ◽  
Welded Joints ◽  
Arc Welding ◽  
Base Material ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Steel Plates ◽  
Wire Saw ◽  
Api 5L X70 Steel ◽  
Submerged Arc

The paper addresses the development of advanced welding technologies with two and three solid wires for joining of HSLA API-5l X70 (High-strength low-alloy) steel plates with thickness of 19.1 mm. The experiments were performed using a multi-wire Submerged Arc Welding (SAW) system that was developed for welding of steels with solid, tubular and cold wires, in different combinations. The main goal of the research was to assess the mechanical performances of the welded joints achieved by multi-wire SAW technology and then to compare them with the single wire variant, as reference system. The welded samples were firstly subjected to NDT control by examinations with liquid penetrant, magnetic particle, ultrasonic and gamma radiation, with the aim of detecting the specimens with flaws and afterwards to reconsider and redesign the corresponding Welding Procedure Specifications (WPS). The defect-free welded samples were subjected to tensile, Charpy V-notch impact and bending testing in order to analyse and report the mechanical behaviour of API-5l X70 steel during multi-wire SAW process. The experimental results were processed and comparatively discussed. The challenge of the investigation was to find the appropriate welding technology which responds simultaneously to the criteria of quality and productivity. Further research on metallurgical behaviour of the base material will be developed, in order to conclude the complete image of the SAW process effects and to understand how the multi-wire technologies affect the mechanical and metallurgical characteristics of the API-5L X70 steel used in pipelines fabrication.

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