Influence of Accelerated Cooling in Critical Zone on the Microstructure and Properties for X100 Pipeline Steel

2011 ◽  
Vol 47 (22) ◽  
pp. 36
Author(s):  
Xiaoyong ZHANG
2013 ◽  
Vol 762 ◽  
pp. 556-561 ◽  
Author(s):  
Yu Liu ◽  
Liu Qing Yang ◽  
Bin Feng ◽  
Shi Wu Bai ◽  
Chang Xue Xu

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.


2016 ◽  
Vol 666 ◽  
pp. 156-164 ◽  
Author(s):  
Shixia Cheng ◽  
Xiaoyong Zhang ◽  
Jianxun Zhang ◽  
Yaorong Feng ◽  
Jing Ma ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yang Zhao ◽  
Ping Liang ◽  
Yanhua Shi ◽  
Yunxia Zhang ◽  
Tao Yang

The pitting susceptibility of passive films formed on X70, X80, and X100 pipeline steels was investigated by means of electrochemical noise (EN) and Mott-Schottky measurements. The EN results were analyzed according to the shot-noise theory and stochastic theory. Pit initiation process was analyzed quantitatively using the Weibull distribution function. Pit growth process was simulated by Gumbel distribution function. The experimental results of Mott-Schottky plots showed that the passive films formed on the three pipeline steels displayed an n-type semiconductor character, and the passive film for X100 pipeline steel has the lowest donor density (ND) among the three passive films. The EN results demonstrated that X100 pipeline steel had the lowest pit initiation rate and pit growth probability, which implied that the X100 pipeline steel had the lowest pitting susceptibility.


2020 ◽  
Vol 9 (4) ◽  
pp. 7838-7849
Author(s):  
Xiaonan Qi ◽  
Hongshuang Di ◽  
Xiaonan Wang ◽  
Zhenguang Liu ◽  
R.D.K Misra ◽  
...  

2014 ◽  
Vol 997 ◽  
pp. 409-414 ◽  
Author(s):  
Ji Xiang Gao ◽  
Lie Jun Li ◽  
Jian Feng Li ◽  
Xiao Ning Wang ◽  
Shao Jun Wei

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.


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