Tensile deformation damage behavior of a high deformability pipeline steel with a ferrite and bainite microstructure

2020 ◽  
Vol 793 ◽  
pp. 139889
Author(s):  
Xingyang Tu ◽  
Xianbo Shi ◽  
Yiyin Shan ◽  
Wei Yan ◽  
Quanqiang Shi ◽  
...  
Keyword(s):  
Tensile Deformation ◽  
Pipeline Steel ◽  
Damage Behavior ◽  
Bainite Microstructure ◽  
High Deformability

Microstructure and Mechanical Properties of X80/X100 High Deformability Pipeline Steel

2011 ◽  
Vol 399-401 ◽  
pp. 139-143
Author(s):  
Dian Xiu Xia ◽  
De Liang Meng ◽  
Shou Yong An ◽  
Yong Lin Kang
Keyword(s):  
Pipeline Steel ◽  
Large Strain ◽  
High Strength ◽  
Longitudinal Direction ◽  
Granular Bainite ◽  
Dual Phase ◽  
Cooling Process ◽  
Bainite Structure ◽  
Lath Bainite ◽  
High Deformability

In the present study, X80 and X100 grade high deformability pipeline steels have been processed by using TMCP and followed two-stage cooling process. The microstructures of the X80HD (HD, high deformability) and X100HD steels were both characterized by ferrite-bainite dual phase. The grains sizes of ferrite were mostly less than 5μm and the volume fractions were about 20~25% in X80HD and 10~15% in X100HD steel. The bainite structure in X80HD steel was granular bainite (GB); while in X100HD steel large amounts of lath bainite (LB) were also formed besides GB, and bainite grains were much finer. Ferrite-bainite dual phase microstructure has large strain hardenability that resulting high strength and high deformability combination. Both the steels exhibit high strength/toughness in transverse direction and high deformability in longitudinal direction. The X100HD steel with more volume of LB and less volume of PF has higher strength but lower deformability than that of X80HD steel.

Control Final Cooling Temperature on High Strength of the Pipeline Radio Yield Influence

2011 ◽  
Vol 117-119 ◽  
pp. 310-314
Author(s):  
Yong Jie Ma ◽  
Xun He ◽  
Guang Liang Zhang
Keyword(s):  
Pipeline Steel ◽  
Steel Production ◽  
High Strength ◽  
Yield Ratio ◽  
X80 Pipeline Steel ◽  
Steel Rolling ◽  
Cooling Temperature ◽  
Lath Bainite ◽  
Bainite Microstructure ◽  
Rolling Technology

In high strength pipeline steel rolling technology, the control of final cooling temperature of different microstructure, different microstructure of pipeline steel tensile strength, yield strength and the effects of different, thus determine its yield ratio differences. The results show that with lath bainite microstructure of the pipeline steel than with acicular ferrite microstructure of the pipeline steel with lower yield ratio, at the same time lath bainite microstructure in small dispersed precipitates in pipeline steel X80 pipeline steel to reduce the yield ratio is beneficial, for high strength pipeline steel production technology to provide the theory basis.

Evaluation of the fracture toughness of X70 pipeline steel with ferrite-bainite microstructure

2017 ◽  
Vol 688 ◽  
pp. 388-395 ◽  
Author(s):  
Liu Ligang ◽  
Xiao Hong ◽  
Li Qiang ◽  
Liu Yu ◽  
Li Peishuai ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Pipeline Steel ◽  
X70 Pipeline Steel ◽  
Bainite Microstructure

Microstructure and Deformation Characteristics of X80 High Deformability Pipeline Steel

2011 ◽  
Vol 299-300 ◽  
pp. 323-327 ◽  
Author(s):  
De Liang Meng ◽  
Yong Lin Kang ◽  
Shou Yong An ◽  
Dian Xiu Xia
Keyword(s):  
Pipeline Steel ◽  
Uniform Elongation ◽  
Polygonal Ferrite ◽  
Granular Bainite ◽  
Lower Yield ◽  
On Line ◽  
Line Process ◽  
Three Stages ◽  
Two Stages ◽  
High Deformability

Two kinds of X80 high deformability pipeline steels have been processed by applying two-stage cooling process (TSC) and heat treatment on-line process (HOP). The microstructure of TSC steel and HOP steel are polygonal ferrite (PF) + quasi-polygonal ferrite (QF) + granular bainite (GB) multiphase and QF + GB+ martensite-austenite (M/A) multiphase respectively. In HOP steel, the volume of M/A is much more and the size is much larger than that in TSC steel. Some degenerated M/A constituents are also observed in HOP steel. The HOP steel has shown higher tensile strength, lower yield ratio and lower uniform elongation than TSC steel. The strain-nI (instantaneous n-value) curve of HOP steel could be divided into two stages and the TSC’s could be separated to three stages.

scholarly journals High-Temperature Ductile Damage Behavior and Modeling of X100 Pipeline Steel

2019 ◽  
Vol 12 (2) ◽  
pp. 161-170
Author(s):  
Lifeng Fan ◽  
◽  
Ge Wang ◽  
Pei Liang ◽  
Jing Ma ◽  
...  
Keyword(s):  
High Temperature ◽  
Pipeline Steel ◽  
Ductile Damage ◽  
Damage Behavior ◽  
X100 Pipeline Steel

Effect of Pre-Deformation on Fatigue Crack Propagation Life of X60 Pipeline Steel

2006 ◽  
Author(s):  
Xinwei Zhao ◽  
Jinheng Luo ◽  
Rong Wang ◽  
Maosheng Zheng ◽  
Baosheng Dong
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Oil And Gas ◽  
Tensile Deformation ◽  
Pipeline Steel ◽  
Fatigue Crack Initiation ◽  
Mechanical Damage ◽  
Fatigue Crack Propagation Life

It is impossible to keep oil and gas pipeline free from defects in fabrication, installation and serving processes. Mechanical damage is one of import causes of pipeline failure accidents. Mechanical damage might endanger the safety of pipelines and even shorten their service life. Pre-tensile deformation of X60 steel is employed to experimentally simulate the influence of dents on the fatigue crack initiation life. The investigation indicates that the fatigue crack propagation life of pre-deformed X60 pipeline steel can be predicted using a previously proposed equation, i.e., da/dN = B(ΔK − ΔKth)2. The threshold ΔKth for fatigue crack propagation decreases with the pre-deformation. The fatigue crack propagation coefficient B increases with the pre-deformation. So pre-deformation accelerates fatigue crack propagation and shortens fatigue life. The result is expected to be beneficial to the understanding of the effect of dents on the safety of pipelines and fatigue life prediction.

Microstructure and Mechanical Properties Analysis of X70 Pipeline Steel with Polygonal Ferrite Plus Granular Bainite Microstructure

2012 ◽  
Vol 161 ◽  
pp. 67-71 ◽  
Author(s):  
Zhan Zhan Zhang ◽  
Xiu Rong Zuo ◽  
Yue Yue Hu ◽  
Ru Tao Li ◽  
Zhi Ming Zhang
Keyword(s):  
Mechanical Properties ◽  
Pipeline Steel ◽  
High Strength ◽  
Polygonal Ferrite ◽  
Granular Bainite ◽  
X70 Pipeline Steel ◽  
Microstructure And Mechanical Properties ◽  
Drop Weight ◽  
Bainite Microstructure ◽  
Strength And Toughness

Microstructure and mechanical properties of X70 pipeline steel with polygonal ferrite plus granular bainite were characterized using tensile tests, Charpy V-notch impact tests, drop weight tear tests, hardness tests and scanning electron microscopy. The results of experiment indicated that X70 pipeline steel with polygonal ferrite plus granular bainite showed an excellent combination of high strength and toughness. The base metal with polygonal ferrite plus granular bainite microstructure exhibited perfect mechanical properties in terms of the transverse yield ratio of 0.81, elongation of 46%, an impact energy of 335 J at -10 °C and a shear area of 90% at 0 °C in the drop weight tear test. The heat affected zone contained coarse grain zone and fine grain zone, which exhibited good low temperature toughness of 216 J at -10 °C. The weld metal primarily consisted of intragranularly nucleated acicular ferrites which led to the high strength and toughness.

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