Quantification of Splitting in X80 Pipeline Steel

2018 ◽  
Author(s):  
Alexey Gervasyev ◽  
Roumen Petrov ◽  
Igor Pyshmintsev ◽  
Chunyong Huo ◽  
Frank Barbaro
Keyword(s):  
Pipe Wall ◽  
Pipeline Steel ◽  
Test Results ◽  
X80 Pipeline Steel ◽  
Pipe Wall Thickness ◽  
Microstructural Parameters ◽  
Controlled Processing ◽  
Ebsd Data ◽  
Depth Analysis ◽  
Electron Back Scattered Diffraction

The results of in-depth analysis of microstructure and crystallographic texture of several industrial batches of line pipes with known full-scale burst test results are presented. Several microstructural features promoting splitting are highlighted and quantified using electron back-scattered diffraction (EBSD) data. The actual splitting intensity is evaluated by means of Charpy tests in the direction of pipe wall thickness (Z-direction) and correlates with the microstructural parameters determined by EBSD analysis. This knowledge can be used in the design of thermo-mechanical controlled processing (TMCP) dedicated to production of splitting-free steel.

Microstructure and Texture Comparison of an Acicular Ferrite Pipeline Steel with Different Hot Rolling Process

2011 ◽  
Vol 399-401 ◽  
pp. 264-267
Author(s):  
Hai Yan Wang ◽  
Hui Ping Ren ◽  
Le Han ◽  
Zi Li Jin ◽  
Hao Sun
Keyword(s):  
Hot Rolling ◽  
Acicular Ferrite ◽  
Pipeline Steel ◽  
Orientation Distribution ◽  
Rolling Process ◽  
X80 Pipeline Steel ◽  
Hot Rolling Process ◽  
X80 Steel ◽  
Hot Rolled ◽  
Electron Back Scattered Diffraction

Microstructure of X80 pipeline steel with different hot rolling process was compared using Optical microscopy (OM), Bulk X-ray texture and micro orientation analysis was carried out by Orientation distribution function (ODF) and Electron back-scattered diffraction (EBSD), to analyze the various texture components of the pipeline steels under two different rolling processes. The results show that the final microstructures under the two schedules both present typical acicular ferrite characteristic. On the other side, the corresponding textures were found mainly comprised of two fibers in the rolling and normal direction in hot rolled X80 steel plate, there were obvious {112} , {110} , and {111} fiber, which seemed to be related with the mechanical properties anisotropy. Therefore, the influences of the microstructure and texture on the anisotropy were also discussed in this paper.

scholarly journals Microstructure and Strengthening/Toughening Mechanisms of Heavy Gauge Pipeline Steel Processed by Ultrafast Cooling

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1323
Author(s):  
Xue-qiang Wang ◽  
Guo Yuan ◽  
Jin-hua Zhao ◽  
Guo-dong Wang
Keyword(s):  
Pipeline Steel ◽  
Bainitic Ferrite ◽  
Strengthening Mechanism ◽  
Grain Refining ◽  
Toughening Mechanisms ◽  
X80 Pipeline Steel ◽  
Pipeline Steels ◽  
X70 Pipeline Steel ◽  
Controlled Processing ◽  
Ultrafast Cooling

Heavy gauge pipeline steels experience a low qualification in drop-weight-tear test properties because of the low cooling capability of conventional thermomechanical controlled processing. To solve this problem, a new-generation thermomechanical-controlled processing technology based on ultrafast cooling was applied to prepare heavy gauge pipeline steels. The microstructure, strengthening and toughening mechanisms of 25.4 mm X70 and 22 mm X80 pipeline steels that were processed by ultrafast cooling were studied. The microstructures of the 25.4 mm X70 and 22 mm X80 pipeline steels consisted of bainitic ferrite, M-A island and acicular ferrite with a large fraction above 85%. The grain size and high-angle grain boundary fraction of X70 pipeline steel were 2.7 μm and 43%, respectively, whereas those of the X80 pipeline steel were 2.4 μm and 45%, respectively. The strengthening and toughening mechanisms were studied for the ultrafast cooling method. The main strengthening mechanism for 25.4 mm X70 pipeline steel was solution and grain-refining strengthening and precipitation strengthening with contributions of ~456 MPa and ~90.5 MPa, respectively. In the 22 mm X80 pipeline steel, the main strengthening mechanism was the solution and grain-refining strengthening, and dislocation strengthening with contributions of ~475 MPa and ~109.8 MPa, respectively.

Microstructure - Texture Related Toughness Anisotropy of API-X80 Pipeline Steel

2006 ◽  
Vol 15-17 ◽  
pp. 840-845 ◽  
Author(s):  
Orlando León García ◽  
Roumen H. Petrov ◽  
Jin Ho Bae ◽  
Leo Kestens ◽  
Ki Bong Kang
Keyword(s):  
Pipeline Steel ◽  
Rolling Direction ◽  
Charpy Impact ◽  
Transition Curve ◽  
Model Parameters ◽  
X80 Pipeline Steel ◽  
Standard Size ◽  
Microstructural Parameters ◽  
Brittle Ductile Transition ◽  
Oriented Parallel

The dependence of Charpy toughness on the microstructure and texture of two industrial grades of API –X80 pipeline steel with a thickness of 15 and 17 mm, respectively, were studied in this work. Standard size Charpy samples with a long axis orientated at 0, 22.5, 45, 67.5 and 90° with respect to the rolling direction of the plate were tested at different temperatures varying from -196°C to 20°C. Microstructure and texture of the plates were studied by means of electron backscattering diffraction (EBSD) and XRD. The highest value of the absorbed energy (440 J) was measured at room temperature in the samples oriented with the long axis parallel to the rolling direction and the minimum values for the same temperature were observed in the samples enclosing an angle of 45° to RD (340J). Statistical model parameters obtained from Charpy impact tests were quantitatively correlated to microstructural parameters by means of a linear regression model with the aim to describe the Brittle-Ductile Transition Curve in terms of microstructural features. Based on dedicated experiments the Brittle Fracture Factor (BFF) parameter was introduced, which quantifies the fraction of the {100} planes oriented parallel to the crack propagation front. It was found that the Charpy toughness anisotropy of the plates in the lower shelf region can not be related only to their crystallographic texture, but to the microstructural anisotropy characterized by the grain size variations i.e. the density of grain boundaries in the different directions. Also the spatial distribution of the 2nd phase plays a determining role in the fracture behavior.

Development of a mathematical model of the influence of wall thickness on the strain rate when profiling pipes by drawing

2020 ◽  
pp. 49-52
Author(s):  
R.A. Okulov ◽  
N.V. Semenova
Keyword(s):  
Mathematical Model ◽  
Strain Rate ◽  
Wall Thickness ◽  
Pipe Wall ◽  
Strain Intensity ◽  
Thickness Strain ◽  
Pipe Wall Thickness

The change in the intensity of the deformation of the pipe wall during profiling by drawing was studied. The dependence of the strain intensity on the wall thickness of the workpiece is obtained to predict the processing results in the production of shaped pipes with desired properties. Keywords drawing, profile pipe, wall thickness, strain rate. [email protected]

Study on Corrosion of X80 Pipeline Steel in Different Water Content of Soil

2014 ◽  
Vol 1015 ◽  
pp. 655-658
Author(s):  
Shu Zhen Yu ◽  
Guang Jun Xu ◽  
Han Hua Song ◽  
Xun Zhu ◽  
Wen We Lu ◽  
...  
Keyword(s):  
Water Content ◽  
High Frequency ◽  
Pipeline Steel ◽  
Electrochemical Corrosion ◽  
High Water ◽  
High Water Content ◽  
Linear Segment ◽  
X80 Pipeline Steel ◽  
The Third ◽  
In The Beginning

The electrochemical corrosion of X80 pipeline steel in Xinzhou’s soil with different water content is tested and analyzed. The corrosion signal time and frequency domain figure show that the corrosion signal fluctuates all the time in 30 days’ test with low water content (14%). The slope of high-frequency linear segment in the potential PSD is smaller than it is at the beginning. In the soil with the middle water content (18%), the intense wave motion lasts for 15 days. The noise fluctuation only exists before the third days when in the high water content soil (22%). After the third day, linear drift can be observed but no transient peak. The slope of high-frequency linear segment changes obviously compared with the situation in the beginning. And the high-frequency white noise appears.

Experimental Analysis of Ratcheting Failure Based on the Piezomagnetic Response of X80 Pipeline Steel

2017 ◽  
Author(s):  
Sheng Bao ◽  
Shengnan Hu ◽  
Yibin Gu
Keyword(s):  
Magnetic Field ◽  
Hysteresis Loop ◽  
Mechanical Response ◽  
Pipeline Steel ◽  
Failure Process ◽  
Failure Behavior ◽  
X80 Pipeline Steel ◽  
Test Analysis ◽  
Number Of Cycles ◽  
The Magnetic Field

The objective of this research is to explore the correlation between the piezomagnetic response and ratcheting failure behavior under asymmetrical cyclic stressing in X80 pipeline steel. The magnetic field variations from cycle to cycle were recorded simultaneously during the whole-life ratcheting test. Analysis made in the present work shows that the piezomagnetic hysteresis loop evolves systematically with the number of cycles in terms of its shape and position. Corresponding to the three-stage process in the mechanical response, piezomagnetic response can also be divided into three principal stages, but the evolution of magnetic parameter is more complex. Furthermore, the loading branch and unloading branch of the magnetic field-stress hysteresis loop separate gradually from each other during ratcheting failure process, leading to the shape of hysteresis loop changes completely. Therefore, the progressive degradation of the steel under ratcheting can be tracked by following the evolution of the piezomagnetic field. And the shape transition of the hysteresis loop can be regarded as an early warning of the ratcheting failure.

Effect of Ferrite Volume Fraction on Mechanical Properties of X80 Pipeline Steel

2014 ◽  
Vol 989-994 ◽  
pp. 212-215
Author(s):  
J. Liu ◽  
G. Zhu ◽  
W. Mao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Work Hardening ◽  
Single Phase ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
X80 Pipeline Steel ◽  
Hardening Behavior ◽  
Two Phases ◽  
Better Than

The effect of volume fraction of ferrite on the mechanical properties including strength, plasticity and wok hardening was systematically investigated in X80 pipeline steel in order to improve the plasticity. The microstructures with different volume fraction of ferrite and bainite were obtained by heat-treatment processing and the mechanical properties were tested. The work hardening behavior was analyzed by C-J method. The results show that the small amount of ferrite could effectively improve the plasticity. The work hardening ability and the ratio of yield/tensile strength with two phases of ferrite/bainite would be obviously better than that with single phase of bainite. The improvement of plasticity could be attributed to the ferrite in which more plastic deformation was afforded.

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