Research and Prospect on Relationship Between Microstructure Characteristics and Strength-Toughness of High Grade Pipeline Steel

2010 ◽  
Author(s):  
Ke Tong ◽  
Chuanjing Zhuang ◽  
Xiaodong He ◽  
Xinli Han ◽  
Juan Song
Keyword(s):  
Grain Size ◽  
Oil And Gas ◽  
Pipeline Steel ◽  
Rapid Development ◽  
In Situ Observation ◽  
High Grade ◽  
Banded Structure ◽  
Microstructure Characteristics ◽  
Effective Grain Size ◽  
Microstructure Characteristic

The strength property of high grade pipeline steel has been obviously improved with the rapid development of the constructing of oil and gas pipelines. And the excellent strength-toughness matching of pipeline steel is very important. The major affecting factor on strength-toughness of pipeline steel is microstructure characteristic. In this paper, the research status of pipeline steel microstructure characteristic including effective grain size, non-metallic inclusions and banded structure is summarized at home and abroad. In addition, the shortcomings of former research on the relationship between microstructure characteristics and strength-toughness are also analyzed for this pipeline steel. On this basis, a solution is put forward to investigate the characterization of effective grain size and micro-mechanical behavior of inclusions and banded structure with the method of electron backscatter diffraction and the method of SEM in situ observation. And the necessities and feasibilities of the solution are discussed.

Effects of M/A Islands Microstructure Characteristic on Mechanic Properties of High Grade Pipeline Steel

2010 ◽  
Author(s):  
Ke Tong ◽  
Xiaodong Shao ◽  
Lixia Zhu ◽  
Qiang Liu ◽  
Jinfeng Li
Keyword(s):  
Volume Fraction ◽  
Pipeline Steel ◽  
Yield Ratio ◽  
Material Strength ◽  
High Grade ◽  
Microstructure Characteristics ◽  
Average Dimension ◽  
Microstructure Characteristic

The microstructure characteristic of martensite/austenite (M/A) islands of X80-1#, X80-2#, X100-3#, X100-4# steel pipelines come from different manufacturer were investigated by OM and SEM contrastively, and the influence of M/A islands microstructure characteristics of pipelines were studied combining with tests of mechanic properties. The result shows that the effect of the M/A islands volume fraction, average dimension, form and distribution on the material strength, yield ratio and toughness were distinct. When the M/A islands distribute uniformly with small size and spherical or crossed strip form, under the certain volume fraction, the pipeline steel exhibits excellent strength-toughness matching.

Effects of Low-Angle Grain Boundaries on the Yield-Strength Ratio of High Grade Pipeline Steels

2010 ◽  
Vol 168-170 ◽  
pp. 1581-1585 ◽  
Author(s):  
Dong Ying Xu ◽  
Hao Yu
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Pipeline Steel ◽  
High Grade ◽  
Strength Ratio ◽  
Pipeline Steels ◽  
Effective Grain Size ◽  
Electron Back Scattered Diffraction

Orientations distribution between grains of two high grade pipeline steels were investigated by electron back-scattered diffraction (EBSD). Then the percentage of low-angle grain boundaries was studied qualitatively to analyze the effect of low-angle grain boundaries on the yield-strength ratio of high grade pipeline steels. From the mode of coordinate deformation and the ability to resist deformation by the grain boundaries, the results show that when the effective grain size are almost the same, the pipeline steel which has the smaller percentage of low-angle grain boundaries, the larger difference between the yield strength and tensile strength, which makes the yield-strength ratio of pipeline steel lower.

Fracture and Crack Propagation Behavior of 560 MPa Microalloyed Pipeline Steel under Different Cooling Schedules

2017 ◽  
Vol 898 ◽  
pp. 1094-1102 ◽  
Author(s):  
Jin Hua Zhao ◽  
Dong Fang Li ◽  
Guo Yuan ◽  
Xue Qiang Wang ◽  
Rui Hao Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Crack Propagation ◽  
Pipeline Steel ◽  
Crack Arrest ◽  
Dominant Factor ◽  
Cooling Schedules ◽  
Effective Grain Size ◽  
Mixed Microstructure ◽  
Low Temperature Toughness

Three kinds of pipeline steel with different microstructures were fabricated by varying cooling schedules during thermo-mechanical controlled processing (TMCP). Charpy impact property of the pipeline steels were obtained, and the fracture and crack-arrest mechanisms were further studied. The results indicated that the steels were classified into two kinds according to their microstructures, the mixture of acicular ferrite (AF), quasi-polygonal ferrite (QF), granular bainite (GB) and small fraction of degenerate pearlite (DP), and the mixed microstructure of AF and GB, respectively. The processed steel with microstructure of AF and GB exhibited more excellent low-temperature toughness and crack-arrest properties with upper shelf energy of ~281 J and energy transition temperature of ~-76°C. The mixed microstructure (AF + GB) possessing smaller effective grain size hindered the propagating of crack and consumed large amount of energy during fracture. The effective grain size of microstructure was the dominant factor controlling low-temperature toughness and crack-arrest properties of pipeline steel, which increased the high-angle boundary length per unit area and further increased the crack propagation energy during fracture.

Evaluation Method of Large Inclusions in High-Grade Pipeline Steel

2013 ◽  
Author(s):  
Yan-hua Li ◽  
Hai-tao Wang ◽  
Ling-kang Ji ◽  
Qiang Chi ◽  
Hong-yuan Chen
Keyword(s):  
Evaluation Method ◽  
Oil And Gas ◽  
Pipeline Steel ◽  
Internal Quality ◽  
Pipeline System ◽  
High Grade ◽  
Efficient Operation ◽  
Steel Pipes ◽  
Transmission Pipeline

Good internal quality of steel pipes is a basic guarantee for the safe and efficient operation of pipeline system. While presence of large inclusions has adverse effect on the mechanical properties, weldability and corrosion resistance of the steel pipes, and then it would bring huge risk to the safe operation of oil and gas transmission pipeline. In order to reduce the risk to a minimum extent, it is quite necessary to analysis and study the characteristics of large inclusions in high grade pipeline steel, and then it would provide evidence for the formulation of level-determination standard of large inclusions during steel pipe acceptance. Optimized production technology such as electromagnetic stirring is put forward accordingly to prevent the occurrence of large inclusions in pipeline steel.

Study on Mechanical Properties Anisotropy of X80 Pipeline Steel

2013 ◽  
Vol 803 ◽  
pp. 413-418
Author(s):  
Qiang Duan ◽  
Jun Yan ◽  
Guo Hui Zhu ◽  
Qing Wu Cai
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Impact Toughness ◽  
Crack Propagation ◽  
Grain Boundaries ◽  
Pipeline Steel ◽  
Rolling Direction ◽  
High Angle ◽  
X80 Pipeline Steel ◽  
Effective Grain Size

The microstructure of X80 pipeline steel in different directions were observed by SEM technique and its effective grain size and misorientation were statistically analyzed by EBSD system. Based on these results, the mechanical properties at 0°, 45° and 90° to the rolling direction of X80 pipeline steel were studied. The results show that, owing to finer grain size and less low-angle grain boundaries, strengths and impact toughness of X80 pipeline steel at 90° direction are optimal. While the pipeline steel possesses finer grain size, more high-angle grain boundaries and less low-angle grain boundaries, the crack propagation is effectively suppressed, then its impact toughness is improved.

scholarly journals Influence of Effective Grain Size on Low Temperature Toughness of High-Strength Pipeline Steel

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3672 ◽  
Author(s):  
Yanlong Niu ◽  
Shujun Jia ◽  
Qingyou Liu ◽  
Shuai Tong ◽  
Ba Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Pipeline Steel ◽  
Rolling Direction ◽  
Charpy Impact ◽  
High Strength ◽  
Cleavage Crack ◽  
Electron Backscattered Diffraction ◽  
Effective Grain Size ◽  
Misorientation Angles

In this study, the series temperature Charpy impact and drop-weight tear test (DWTT) were investigated, the misorientation angles among structural boundaries where the cleavage crack propagated were identified, and angles of {100} cleavage planes between adjacent grains along the cleavage crack propagated path were calculated in five directions (0°, 30°, 45°, 60°, and 90° to the rolling direction) of high-grade pipeline steel. Furthermore, the effective grain size (grain with misorientation angles greater than 15°) was redefined, and the quantitative influences of the redefined effective grain size on Charpy impact and DWTT is also discussed synthetically. The results showed that the microstructure presented a typical acicular ferrite characteristic with some polygonal ferrite and M-A islands (composed of martensite and retained austenite), and the distribution of the high-angle grain boundaries were mainly distributed in the range of 45°–65° in different directions. The Charpy impact energy and percent shear area of DWTT in the five directions increased with refinement of the redefined effective grain size, composed of grains with {100} cleavage planes less than 35° between grain boundaries. The ductile-to-brittle transition temperature also decreased with the refining of the redefined effective grain size. The redefined effective grain boundaries can strongly hinder fracture propagation through electron backscattered diffraction analysis of the cleavage crack path, and thus redefined effective grain can act as the effective microstructure unit for cleavage.

scholarly journals On the role of grain size on slurry erosion behavior of a novel medium-carbon, low-alloy pipeline steel after induction hardening

Wear ◽  
2021 ◽  
pp. 203678
Author(s):  
Vahid Javaheri ◽  
Oskari Haiko ◽  
Saeed Sadeghpour ◽  
Kati Valtonen ◽  
Jukka Kömi ◽  
...  
Keyword(s):  
Grain Size ◽  
Pipeline Steel ◽  
Induction Hardening ◽  
Slurry Erosion ◽  
Medium Carbon ◽  
Erosion Behavior

scholarly journals Convection Enhanced Delivery in the Setting of High-Grade Gliomas

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 561
Author(s):  
Chibueze D. Nwagwu ◽  
Amanda V. Immidisetti ◽  
Michael Y. Jiang ◽  
Oluwasegun Adeagbo ◽  
David C. Adamson ◽  
...  
Keyword(s):  
Rapid Development ◽  
Systemic Exposure ◽  
Therapeutic Index ◽  
High Grade Glioma ◽  
High Grade ◽  
Clinical Experiences ◽  
Convection Enhanced Delivery ◽  
Drug Concentrations ◽  
Infiltrative Growth Pattern ◽  
High Grade Gliomas

Development of effective treatments for high-grade glioma (HGG) is hampered by (1) the blood–brain barrier (BBB), (2) an infiltrative growth pattern, (3) rapid development of therapeutic resistance, and, in many cases, (4) dose-limiting toxicity due to systemic exposure. Convection-enhanced delivery (CED) has the potential to significantly limit systemic toxicity and increase therapeutic index by directly delivering homogenous drug concentrations to the site of disease. In this review, we present clinical experiences and preclinical developments of CED in the setting of high-grade gliomas.

The Method of Eliminating Banded Structure and the Effects of Banded Structure on the Transverse Properties in 20G Steel

2013 ◽  
Vol 347-350 ◽  
pp. 1171-1175 ◽  
Author(s):  
Bin Wang ◽  
Hong Mei Hu ◽  
Cui Zhou
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Stress Concentration ◽  
Base Metal ◽  
Metallic Inclusion ◽  
Banded Structure ◽  
Grain Sizes ◽  
Fine Grain ◽  
Treatment Processes ◽  
Metallic Inclusions

The transverse properties were inferior to the longitudinal properties for the existence of banded structure in 20G steel. In order to eliminate the banded structure and improve the transverse performance of 20G steel, different heat treatment processes were adopted. The results showed that conventional normalizing could reduce the banded structure and refine the grain sizes. When 20G was heated with 10°C/min heating rated and then held at 920°C for 2h, the banded structure in the steel was almost eliminated and the microstructure was homogeneous with fine grain size, the strength increased by 14%. The non-metallic inclusion and carbide in the microstructure leaded to stress concentration and separation with the base metal. To some extent, heat treatment can improve the distribution and form of non-metallic inclusions.

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