Effects of Microstructural Inhomogeneity on HIC Susceptibility and HIC Evaluation Methods for Linepipe Steels for Sour Service

2014 ◽  
Author(s):  
Kyu Tae Kim ◽  
Sang Gi Ko ◽  
Jong Man Han
Keyword(s):  
Deep Sea ◽  
Acicular Ferrite ◽  
Evaluation Methods ◽  
Polygonal Ferrite ◽  
Internal Quality ◽  
Pipe Steels ◽  
Line Pipe ◽  
Microstructural Inhomogeneity ◽  
Hydrogen Induced Cracking ◽  
Sour Service

It has been well documented that slab internal quality is one of the key factors for reduced susceptibility of hydrogen induced cracking (HIC) in line pipe steels designed for sour gas service. In addition, the creation of a homogeneous microstructure which is heavily influenced by the slab internal quality is also a critical key parameter to reduce the HIC susceptibility in higher strength line pipe steel grade X60 and above. For the application of deep sea linepipe exposed to higher external pressure environments, heavy gauge in combination with higher strength steel is essential. Homogeneity of the steel microstructure is a key to success for thicker plates used in sour service HIC applications in combination with a deep sea environment. In this paper, various microstructures were compared along with an evaluation of the effects of the various microstructures on HIC susceptibility in grades X52, X65 and X70 designed for sour service. The various microstructures compared consisted of polygonal ferrite and pearlite in the X52 and polygonal ferrite, pearlite, acicular ferrite and bainite in the X65 and X70. The effect of microstructural inhomogeneity on HIC susceptibility was comparatively lower for the X52 than that of the X65 and X70. The microstructure of grade X65 and X70 were different due to the different conditions of rolling and cooling that were applied. Grades X65/X70 had a microstructure of polygonal ferrite/pearlite with bainite islands that resulted in a high crack length ratio (CLR) value caused by different hardness regions across the microstructural matrix. A homogeneous fine acicular ferrite microstructure produced by optimizing temperature control during rolling and cooling showed no hydrogen induced cracking. In addition, this alloy/process/microstructure design resulted in improved toughness results in low temperature drop weight tear test (DWTT). This paper will describe the successful production results of plate and pipe for high strength heavier gauge line pipe steels with highly homogeneous microstructures designed for sour service by controlling chemical design and process conditions in rolling and cooling. In addition, HIC evaluation methods utilizing both a traditional NACE TM0284 method versus that of a Scan-UT method were conducted and compared. A proposal to make the NACE TM0284 testing method more reliable by using Scan-UT method will be presented.

Hydrogen-Induced Cracking of Line Pipe Steels Used in Sour Service

CORROSION ◽  
1993 ◽  
Vol 49 (7) ◽  
pp. 531-535 ◽  
Author(s):  
R. W. Revie ◽  
V. S. Sastri ◽  
M. Elboujdaini ◽  
R. R. Ramsingh ◽  
Y. Lafrenière
Keyword(s):  
Pipe Steels ◽  
Line Pipe ◽  
Hydrogen Induced Cracking ◽  
Sour Service

ULTRASONIC EVALUATION OF RESISTANCE TO HYDROGEN-INDUCED CRACKING OF LINE PIPE STEELS

1987 ◽  
pp. 359-365
Author(s):  
J.C. ALBERT ◽  
O. CASSIER ◽  
H. MARGOT-MARETTE ◽  
G. BARDOU ◽  
P. VIRLOUVET
Keyword(s):  
Pipe Steels ◽  
Line Pipe ◽  
Ultrasonic Evaluation ◽  
Hydrogen Induced Cracking

Hydrogen Induced Cracking Susceptibility of High-Strength Line Pipe Steels

CORROSION ◽  
1986 ◽  
Vol 42 (6) ◽  
pp. 337-345 ◽  
Author(s):  
K. Matsumoto ◽  
Y. Kobayashi ◽  
K. Ume ◽  
K. Murakami ◽  
K. Taira ◽  
...  
Keyword(s):  
High Strength ◽  
Pipe Steels ◽  
Line Pipe ◽  
Hydrogen Induced Cracking

Use of C-Mn Linepipe for High H2S Service

2018 ◽  
Author(s):  
David Baxter ◽  
Erling Østby ◽  
Steven Chong ◽  
Asle Venås
Keyword(s):  
Internal Surface ◽  
Hard Material ◽  
Thickness Direction ◽  
Pipe Steels ◽  
Line Pipe ◽  
High Partial Pressure ◽  
Service Projects ◽  
Girth Welds ◽  
Mn Steel ◽  
Sour Service

There have been recent incidents associated with cracking and leaks in C-Mn line pipe steels exposed to high H2S service. The incidents led to pipeline replacement with very expensive CRA clad pipeline causing substantial project delays and project cost escalations. The incidents occurred when TMCP ACC steels were exposed to severe Region 3 environment as per domain diagram in NACE MR0175 (high partial pressure of H2S). The leaks were associated with longitudinal cracking which initiated at hard zones present on the parent pipe internal surface, and possibly also in girth welds. The hard spots were observed to be contained within a very shallow depth of the ID surface of the pipe. The pipe microstructure beyond the thin layer of the hard zones at the ID surface did not contain hard material. However, the cracks propagated through the parent pipe normal microstructure in the through thickness direction. Several of the operators are now concerned and uncertain on how to ensure the integrity of C-Mn pipelines in similar severe sour environments. Some operators have therefore introduced more stringent requirements for sour environment resulting in significant challenges to manufacture of line pipes and qualification of welding procedures that meet these new requirements. We also see different requirements being imposed by different operators. The use of CRA, clad/lined pipes or other exotic materials can solve the challenges, but are very expensive and can significantly reduce margins and make several sour service projects less viable. Several R&D institutions have already started to study the phenomena. DNV GL have also initiated a broad JIP that will look into the challenges, with the objective of developing an industry guideline for use of C-Mn line pipe for high H2S service. This paper will give background on the challenges associated with using C-Mn steel in high H2S service, describe the various uncertainties in detail, and describe how the JIP will address the challenges on a broad basis.

Development of High-Strength Heavy-Wall Sour-Service Seamless Line Pipe for Deep Water by Applying Inline Heat Treatment

2004 ◽  
Author(s):  
Yuji Arai ◽  
Kunio Kondo ◽  
Masahiko Hamada ◽  
Nobuyuki Hisamune ◽  
Nobutoshi Murao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Deep Water ◽  
High Strength ◽  
Carbon Equivalent ◽  
Medium Size ◽  
Treatment Technology ◽  
Line Pipe ◽  
Hydrogen Induced Cracking ◽  
Microalloying Elements ◽  
Sour Service

High strength heavy wall sour service seamless line pipe suitable for deep water applications has been developed by Sumitomo Metal Industries, Ltd.,. This paper describes the concept of developing these pipes applying inline heat treatment technology, equipped in a newly constructed, medium-size seamless mill. Increasing hardenability through inline heat treatment achieved higher strength (X70) for heavy wall pipe (40mm) even though carbon equivalent was lower than in a conventional Q&T process. Good toughness was obtained by the control of microalloying elements such as titanium or sulfur. The produced pipe passed the hydrogen-induced cracking (HIC) test conducted according to NACE TM 0284 solution A. Controlling the microstructure and suppressing maximum hardness, utilizing the uniform quenching facility during inline heat treatment, contributed to the test result. Satisfactory data on weldability for practical use were also obtained.

Metallographic study of hydrogen-induced cracking in line pipe steels

JOM ◽  
1976 ◽  
Vol 28 (5) ◽  
pp. 1-10
Author(s):  
A. P. Coldren ◽  
G. Tither
Keyword(s):  
Pipe Steels ◽  
Line Pipe ◽  
Metallographic Study ◽  
Hydrogen Induced Cracking
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