Microstructure and Properties of Pipeline Steel with Acicular Ferrite

2007 ◽  
pp. 4750-4755
Author(s):  
Lei Zheng ◽  
Shan Gao
Keyword(s):  
Acicular Ferrite ◽  
Pipeline Steel ◽  
Microstructure And Properties

Continuous Cooling Phase Transformation Rules of High Nb X80 Pipeline Steel

2016 ◽  
Vol 850 ◽  
pp. 916-921
Author(s):  
Pei Pei Xia ◽  
Liu Qing Yang ◽  
Xiao Jiang Guo ◽  
Ye Zheng Li
Keyword(s):  
Phase Transformation ◽  
Cooling Rate ◽  
Acicular Ferrite ◽  
Thermal Deformation ◽  
Pipeline Steel ◽  
Phase Transformation Temperature ◽  
X80 Pipeline Steel ◽  
Continuous Cooling ◽  
Simulation Testing ◽  
Cooling Phase

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.

Microstructure and Properties of Longitudinal Submerged Arc Welded Linepipes for Deep-Sea Pipeline

2014 ◽  
Vol 997 ◽  
pp. 409-414 ◽  
Author(s):  
Ji Xiang Gao ◽  
Lie Jun Li ◽  
Jian Feng Li ◽  
Xiao Ning Wang ◽  
Shao Jun Wei
Keyword(s):  
Deep Sea ◽  
Oil And Gas ◽  
Pipeline Steel ◽  
Test Methods ◽  
Granular Bainite ◽  
Thick Wall ◽  
Fine Crystal ◽  
Microstructure And Properties ◽  
Welded Pipe ◽  
Submerged Arc

This paper provides description of deep-sea JCOE process of longitudinal submerged-arc welded pipe.The test methods including optical microscopy and tensile,toughness,drop weight tear are applied, the microstructure and properties of deep-sea pipeline steel and deep longitudinal submerged arc welded pipe with thick wall are studied. The results indicates that pipeline steel of substrate organization to acicular ferrite mainly and deep with longitudinal submerged-arc welded thick wall pipe welding HAZ of rough crystal area and fine crystal area respectively main for granular bainite and associate polygon ferrite organization; Deep-sea LSAW steel pipe has reasonable control parameters for process, and its performance meets DNV-OS-F101:2007 specification and user project technology conditions,used for materiels of pipeline steel for China deep-sea oil and gas pipeline project.

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

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

Microstructure and properties of pipeline steel with a ferrite/martensite dual-phase microstructure

2011 ◽  
Vol 62 (8) ◽  
pp. 801-806 ◽  
Author(s):  
Rutao Li ◽  
Xiurong Zuo ◽  
Yueyue Hu ◽  
Zhenwei Wang ◽  
Dingxu Hu
Keyword(s):  
Pipeline Steel ◽  
Dual Phase ◽  
Microstructure And Properties

Precipitation behaviors of X80 acicular ferrite pipeline steel

2011 ◽  
Vol 18 (3) ◽  
pp. 309-313 ◽  
Author(s):  
Ai-min Zhao ◽  
Yan Wang ◽  
Yin-li Chen ◽  
Di Tang ◽  
Xu-tao Gao ◽  
...  
Keyword(s):  
Acicular Ferrite ◽  
Pipeline Steel

Physical Simulation on Microstructure and Properties for Weld HAZ of X100 Pipeline Steel

2013 ◽  
Vol 762 ◽  
pp. 556-561 ◽  
Author(s):  
Yu Liu ◽  
Liu Qing Yang ◽  
Bin Feng ◽  
Shi Wu Bai ◽  
Chang Xue Xu
Keyword(s):  
Heat Input ◽  
Physical Simulation ◽  
Pipeline Steel ◽  
Control Measures ◽  
Coarse Grain ◽  
Test Machine ◽  
Steel Weld ◽  
Double Pass ◽  
Microstructure And Properties ◽  
X100 Pipeline Steel

In this paper, the simulation heat affected zone (HAZ) continuous cooling transformation (SH-CCT) diagram of X100 pipeline steel was drew by using Gleeble 3500-HS thermal/mechanics simulation test machine, and the microstructure and properties of the HAZ of single-pass/double-pass welding were simulated and studied. The results show that the hardening trend of X100 pipeline steel weld coarse grain HAZ (CGHAZ) is significant when using the small welding heat input. To prevent the hardening of weld CGHAZ and reduce the cold cracking sensitivity, moderate heat input welding specification (between 12 and 18 kJ/cm) and weld preheating process (between 100 and 150°C) should be adopted. When appearing obvious embrittlement, the microstructure of double-pass weld intercritically reheated coarse grain HAZ (ICCGHAZ) of X100 pipeline steel is mainly upper bainite, the precipitation and the chain-like distribution of quantity more martensite-austenite (M-A) constituents in austenite grain boundaries is one of the main reasons leading to toughness deterioration. In conclusion, optimization control measures on the microstructure and properties of X100 pipeline steel weld HAZ are presented by above comprehensive analysis.

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