High strength line pipe steel plates based on TM-processing

AbstractThe microstructural characterizations and partitioning of carbon element in the weld heat affected zones of a commercial API 5L X60 line pipe steel were studied by applying a high speed heating and cooling dilatometry technique in the present research work. The hollow cylindrical specimens were quickly heated to 1000°C, soaked for only 5 s followed by continuous cooling to ambient temperature. Besides the construction of CCT diagram of this high strength low alloy steel using the dilatation data, the hardening response, microstructural features and carbon partitioning of weld simulated specimens were investigated. The obtained results showed that the hardening response of samples increased from 142 to 261HV10kg with increasing cooling rates. These hardening variations were attributed to the changes in microstructural features and carbon partitioning that occurred between the microconstituents present in the microstructures of weld simulated samples.

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Influence of Softened Heat-affected Zone on Stress Oriented Hydrogen Induced Cracking of a High Strength Line Pipe Steel.

ISIJ International ◽

10.2355/isijinternational.35.1190 ◽

1995 ◽

Vol 35 (10) ◽

pp. 1190-1195 ◽

Cited By ~ 5

Author(s):

Akihiko Takahashi ◽

Hiroyuki Ogawa

Keyword(s):

Heat Affected Zone ◽

Pipe Steel ◽

High Strength ◽

Line Pipe ◽

Hydrogen Induced Cracking ◽

Line Pipe Steel

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EBSD Analysis of Fracture Separation in X80 Line Pipe Steel

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2008-61689 ◽

2008 ◽

Cited By ~ 1

Author(s):

Yang Li ◽

Li Meng ◽

Guanfa Lin ◽

Xinli Han ◽

Chunyong Huo ◽

...

Keyword(s):

Hot Rolling ◽

Pipe Steel ◽

Charpy Impact ◽

Heat Stability ◽

Tensile Tests ◽

Steel Plates ◽

Line Pipe ◽

Impact Tests ◽

Average Grain Size ◽

Line Pipe Steel

During testing pipe and steel for 2nd china west-east gas pipeline (WEGP), fracture separation was found in X80 line pipe steel plates in tensile tests, charpy impact tests and DWTT tests. In this paper, fracture separation is investigated by using EBSD technique to analyze microstructure and to compare it with microstructure of the material after annealing. Results show that there are obvious texture of {111} <110> and {110} <001> in hot rolling plate, but a reduction of this two textures and a new texture of {110} <111> are found after annealing at 700°C for 2 hours. It is found in charpy impact tests that the {111} <110> micro-texture, as a main factor leading to fracture separation was eliminated in annealed specimens. The average grain size of specimen changed from 2.2687μm to 2.8362μm comparing with hot rolling plate because of the decomposition of Bainite. The results of Orientation Imaging displayed that the proportion of substructure and the distribution of misorientation of grain boundary of annealed specimens did not changed remarkably in contrast to the original ones. It is concluded that, X80 steel has well heat stability.

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Effect of Micro-Texture on Fracture Separation in X80 Line Pipe Steel

2008 7th International Pipeline Conference, Volume 3 ◽

10.1115/ipc2008-64198 ◽

2008 ◽

Author(s):

Yang Li ◽

Xinli Han ◽

Lingkang Ji ◽

Yaorong Feng ◽

Chunyong Huo

Keyword(s):

Hot Rolling ◽

Pipe Steel ◽

Charpy Impact ◽

Heat Stability ◽

Tensile Tests ◽

Steel Plates ◽

Line Pipe ◽

Impact Tests ◽

Average Grain Size ◽

Line Pipe Steel

During tests on pipe and steel for the 2nd west-east gas pipeline project (WEPP) in china, fracture separation was found in X80 line pipe steel plates in tensile tests, charpy impact tests and DWTT tests. In this paper, fracture separation is investigated by using EBSD technique to analyze microstructure and compare it with microstructure transformation of the material after annealing. Results show that there are obvious texture of {111} <110> and {110} <001> in hot rolling plate, but a reduction of this two textures and a new texture of {110} <111> are found after annealing at 700°C for 2 hours. It is found in charpy impact tests that {111} <110> micro-texture as a main factor leading to fracture separation was eliminated in annealed specimens. The average grain size of specimen changes from 2.2687μm to 2.8362μm comparing with hot rolling plate because of the decomposition of Bainite. Results of Orientation Imaging display that the proportion of substructure and the distribution of misorientation of grain boundary of annealed specimens do not changed remarkably in contrast to the original ones. It is concluded that, X80 steel has well heat stability.

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Exploiting a Simple Spectrophotometric Method for the Determination of Manganese in High Strength Line Pipe Steels

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.284-286.1158 ◽

2011 ◽

Vol 284-286 ◽

pp. 1158-1164

Author(s):

Xiaodong Shao

Keyword(s):

Spectrophotometric Method ◽

Pipe Steel ◽

High Strength ◽

Ammonium Persulfate ◽

Pipe Steels ◽

Line Pipe ◽

Relative Standard ◽

Characteristic Wavelength ◽

Line Pipe Steel

The use of high strength line pipe steels is beneficial for the reduction the cost of gas transmission pipelines by enabling high pressure transmission of large volumes of gas. The high strength line pipe steels will become the preferred materials for modern natural gas transmission pipeline. It was well known that manganese was an important element in the high strength line pipe steels. In this paper, a simple spectrophotometric method was described for determination of manganese in high strength line pipe steels. The method was based on the oxidation-reduction reaction between ammonium persulfate and manganese(II) producing manganese(VII) in the presence of silver nitrate as a catalyst. The characteristic wavelength of maximum absorption of manganese(VII) was obtained locating at 530 nm. Under the optimum reaction conditions the absorption value was proportional to the concentration of manganese in the range of 0.18%~2.0% (R2 = 0.9997), and the relative standard deviation was less than 3.0% (n=5). The proposed method was applied successfully to determine manganese in API grade X80 line pipe steel and API grade X70 line pipe steel samples.

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