Precipitation behaviors of X80 acicular ferrite pipeline steel

The microstructural evolution of the high Nb X80 pipeline steel in Continuous Cooling Transformation (CCT) by Gleeble-3500HS thermal mechanical simulation testing system was studied, the corresponding CCT curves were drawn and the influence of some parameters such as deformation and cooling rate on microstructure of high Nb X80 pipeline steel was analyzed. The results show that as cooling rate increased, the phase transformation temperature of high Nb X80 steel decreased, with the microstructure transformation from ferrite-pearlite to acicular ferrite and bainite-ferrite. When cooling rate was between 20°C/s and 30°C/s, the microstructure was comparatively ideal acicular ferrite, thermal deformation accelerates phase transformation notably and made the dynamic CCT curves move upward and the initial temperature of phase transformation increase obviously. Meanwhile the thermal deformation refined acicular ferrite and extended the range of cooling rate accessible to acicular ferrite.

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Acicular ferrite nucleation mechanism in laser-MAG hybrid welds of X100 pipeline steel

Materials Letters ◽

10.1016/j.matlet.2021.130603 ◽

2021 ◽

pp. 130603

Author(s):

Xiaonan Qi ◽

Xiaonan Wang ◽

Hongshuang Di ◽

Xinjun Shen ◽

Pengcheng Huan ◽

...

Keyword(s):

Acicular Ferrite ◽

Pipeline Steel ◽

Nucleation Mechanism ◽

X100 Pipeline Steel ◽

Ferrite Nucleation

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Mechanical Properties and CO2 Corrosion Behavior of High Strength and Toughness X80 Pipeline Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.1709 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 1709-1712

Author(s):

Li Dong Wang ◽

Feng Lei Liu ◽

Hui Bin Wu

Keyword(s):

Corrosion Rate ◽

Corrosion Behavior ◽

Acicular Ferrite ◽

Pipeline Steel ◽

High Strength ◽

Strengthening Mechanism ◽

Granular Bainite ◽

X80 Pipeline Steel ◽

Better Than ◽

Strength And Toughness

A type of X80 grade high strength and toughness pipeline steel was designed and researched. The strengthening mechanism of the steel was analyzed by SEM, TEM and XRD, and the CO2corrosion behavior of the steel was simulated by high-temperature and high-pressure autoclave. The result shows that the microstructure of the base metal is mainly acicular ferrite with a small amount of granular bainite. Acicular ferrite consists of laths which occlude and interweave with each other, and there are many dislocation and carbonitrides distributing in acicular ferrite, which made the pipeline steel have good strength and toughness. Under the simulation of the actual working conditions, the activity of reactants is low at 30°C, so the corrosion rate is smaller at this temperature; the maximum of corrosion rate occurs at 60°C; when the temperature increases to 90°C, the corrosion rate is lower than that of 60°C, that is because hindering corrosion effect which take by the acceleration deposit of corrosion product is better than the acceleration corrosion reactions.

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Precipitation behaviors of X70 acicular ferrite pipeline steel

Journal of University of Science and Technology Beijing Mineral Metallurgy Material ◽

10.1016/s1005-8850(06)60106-0 ◽

2006 ◽

Vol 13 (6) ◽

pp. 523-527 ◽

Cited By ~ 11

Author(s):

Hao Yu ◽

Yi Sun ◽

Qixiang Chen ◽

Haitao Jiang ◽

Lihong Zhang

Keyword(s):

Acicular Ferrite ◽

Pipeline Steel

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Challenge of mechanical properties of an acicular ferrite pipeline steel

Materials Science and Engineering A ◽

10.1016/j.msea.2006.05.029 ◽

2006 ◽

Vol 431 (1-2) ◽

pp. 41-52 ◽

Cited By ~ 105

Author(s):

Fu-Ren Xiao ◽

Bo Liao ◽

Yi-Yin Shan ◽

Gui-Ying Qiao ◽

Yong Zhong ◽

...

Keyword(s):

Mechanical Properties ◽

Acicular Ferrite ◽

Pipeline Steel

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.264 ◽

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.

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Continuous Cooling Transformation Behavior of X70 Pipeline Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.690-693.2205 ◽

2013 ◽

Vol 690-693 ◽

pp. 2205-2209

Author(s):

Hong Mei Yang

Keyword(s):

Cooling Rate ◽

Hot Deformation ◽

Acicular Ferrite ◽

Transformation Temperature ◽

Pipeline Steel ◽

Continuous Cooling Transformation ◽

X70 Pipeline Steel ◽

Continuous Cooling ◽

Transformation Curve ◽

Continuous Cooling Transformation Curve

The continuous cooling transformation behaviors were researched on X70 pipeline steel through two pass deformation and non-deformed austenite using Gleeble-3500 thermal mechanical simulator, and static continuous cooling transformation curve and dynamic continuous cooling transformation curve were measured through thermal dilation method and metallographic method. The influence of cooling rate and deformation parameters on microstructure was analyzed. The results show that the hot deformation accelerates the acicular ferrite and polygonal ferrite phase transformation, increases the starting transformation temperature and the finishing transformation temperature significantly, and shifts the CCT curve moving upward to the left side corner. Acicular ferrite is obtained in practice using accelerated cooling rate after deformation Acicular ferrite can be obtained in wider range of cooling rates, and microstructure and island structure is finer through hot deformation.

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