Guidelines for Production of API Pipelines Steels Suitable for Hydrogen Induced Cracking (HIC) Service Applications

2010 ◽  
Author(s):  
Douglas G. Stalheim ◽  
Bernhard Hoh
Keyword(s):  
Mechanical Property ◽  
Natural Gas ◽  
Pipeline Steel ◽  
Steel Production ◽  
The Other ◽  
Corrosion Mechanism ◽  
Pipeline Steels ◽  
Hydrogen Induced Cracking ◽  
Oil And Natural Gas ◽  
Sour Service

Worldwide oil and natural gas reserves can be classified as either sweet or sour service. The sour service classified oil and natural gas reserves contain some level of H2S making the product flowing through a steel pipeline corrosive. Due to this, the majority of the oil and natural gas reserves that have been drilled are of the sweet service nature. However as demand continues and supplies change, many of the remaining oil and natural gas reserves contain the H2S component and are of a sour service nature. These oil and natural gas reserves containing the H2S component through a corrosion mechanism will allow for diatomic hydrogen — in the presence of moisture — to disseminate to monatomic hydrogen and diffuse into the pipeline steel microstructure. Depending on the microstructure and level of cleanliness the monatomic hydrogen can become trapped at areas of high residual stress, recollect to diatomic hydrogen and creating partial pressures that exceed the tensile strength of the steel resulting in cracking. Therefore transmission pipelines are being built to transport sour service oil or natural gas requires steels with hydrogen induced cracking (HIC) resistance. Alloy designs, steel making processing, continuous casting, plate or strip rolling, pipe forming, and last not least corrosion testing are all key components in producing pipeline steels that are resistant to HIC applications and meeting the NACE TM0284 specifications. However, producing steels that have good HIC performance do not necessarily meet other mechanical property requirements such as strength and YT ratios. Balance has to be achieved to meet not only the HIC requirements but the other required mechanical properties. Mastering this complex HIC process poses a serious challenge to pipe producers and their primary material suppliers. The capability of producing HIC steel grades according to critical specifications and/or standards clearly distinguishes excellent steel producers from good steel makers. This paper will discuss the basics of the hydrogen induced cracking phenomenon, the requirements of the NACE TM0284 specification and give guidelines for steel production of API pipeline steels that not only can meet the specification requirements the NACE testing but also fulfill the other mechanical property requirements.

The decoupling states of CO2 emissions in the Chinese transport sector from 1994 to 2012: A perspective on fuel types

2018 ◽  
Vol 29 (4) ◽  
pp. 591-612 ◽  
Author(s):  
Dayong Wu ◽  
Changwei Yuan ◽  
Hongchao Liu
Keyword(s):  
Natural Gas ◽  
Sustainable Transportation ◽  
Policy Implications ◽  
The Other ◽  
Fuel Oil ◽  
Transport Sector ◽  
Aggregate Level ◽  
Heavy Fuel Oil ◽  
Negative State ◽  
Oil And Natural Gas

This paper analyzes the decoupling states between CO2 emissions and transport development in China from 1994 to 2012. The results indicate that, at the aggregate level, the Chinese transport sector is far from reaching the decoupling state. Negative decoupling or non-decoupling years account for 72.2% of the study period. At the disaggregated level, the decoupling states between CO2 emissions and eight primary fuels are as follows: raw coal and coke are in the absolute decoupling state; crude oil, gasoline and diesel are in the weak negative state; and the other three types (kerosene, heavy fuel oil, and natural gas) are in the strong negative decoupling state. Policy implications underneath the identified decoupling states are also revealed to help China build a more sustainable transportation system.

Effect of Loading History on Hydrogen Content in Pipeline Steels

2002 ◽  
Author(s):  
N. M. Vadhwana ◽  
W. Chen
Keyword(s):  
Yield Strength ◽  
Hydrogen Content ◽  
Pipeline Steel ◽  
High Strength ◽  
The Other ◽  
Loading Conditions ◽  
Line Pipe ◽  
Pipeline Steels ◽  
Pronounced Increase ◽  
Charging Time

The application of high strength pipeline steels for oil and gas transmission is believed to provide greater gas flow capacity due to increased design pressure, and reduced line pipe cost due to material tonnage savings. However, the use of high strength pipeline steels is concerned with high risk of brittle failures such as hydrogen induced cracking, fractures due to low ductility. In this study, three grades of modern pipeline steel (X65, X80, X100) were examined to determine their susceptibility to hydrogen permeation and hydrogen trapping under the influence of various mechanical loading conditions. The steel samples were placed in a solution of sulfuric acid poisoned with arsenic trioxide to create an environment where hydrogen can enter the steel. Initially, round bar samples were charged for various times at a low current density to establish that 24 hours was a sufficient charging time for the three steels. Tensile samples were loaded and held at stress levels corresponding to the respective yield strength and the amount of hydrogen entering the steel was then measured. The stress, normalized to the yield strength, and hydrogen contents, normalized to as received contents, were used to rank the three steel grades and to find the steel that was the most susceptible to hydrogen entry. For the samples charged prior to loading, two times as much diffusible hydrogen was found in the X100 as compared to the other steels, but the trapped hydrogen content was equivalent. Four loading conditions were used for each grade of steel: 1) 2% strain; 2) 2% strain and hold at load for 24 hours; 3) 2% strain then 100 cycles at R = 0.1; and 4) 2% strain, 100 cycles at R = 0.1 then hold at load for 24 hours. For the loaded samples, the amount of hydrogen, both diffusible and trapped increased with load severity, with the highest amounts found in the highest grades of steel. The most pronounced increase was not found in the X100, but in the X-80 steel. Micro structural features, such as banded structure, seemed to have a more prominent role on the hydrogen content of the X100 than in the other steels as it seemed less affected by the loading condition than by charging time.

scholarly journals From Scarcity to Abundance: The New Geopolitics of Energy

2018 ◽  
Vol 1 (1) ◽  
pp. 181
Author(s):  
Michael Klare
Keyword(s):  
Climate Change ◽  
Foreign Policy ◽  
Natural Gas ◽  
Hydraulic Fracturing ◽  
Persian Gulf ◽  
American Foreign Policy ◽  
The Other ◽  
Shale Formations ◽  
Oil And Natural Gas ◽  
The Persian Gulf

For most of the Petroleum Age, and even as recently as ten years ago, the politics of energy were largely governed by perceptions of scarcity: the assumption that global supplies of most primary fuels were finite and would eventually prove insufficient to satisfy rising worldwide demand, resulting in intense competition over what remained.  The enduring prevalence of this view led many oil-importing nations to establish close ties with their major foreign suppliers and to employ force on occasion to ensure the safety of overseas supply lines.  This outlook guided American foreign policy for over half a century, resulting in several U.S. interventions in the Persian Gulf area.  Recently, however, a combination of technological and political considerations – the introduction of hydraulic fracturing (“fracking”) to extract oil and natural gas from previously inaccessible shale formations on one hand and rising concern over climate change on the other – has largely extinguished the perception of scarcity, introducing entirely new dynamics into the geopolitics of energy.

An extensive study of hydrogen-induced cracking susceptibility in an API X60 sour service pipeline steel

2016 ◽  
Vol 41 (7) ◽  
pp. 4185-4197 ◽  
Author(s):  
M.A. Mohtadi-Bonab ◽  
M. Eskandari ◽  
K.M.M. Rahman ◽  
R. Ouellet ◽  
J.A. Szpunar
Keyword(s):  
Pipeline Steel ◽  
Extensive Study ◽  
Hydrogen Induced Cracking ◽  
Sour Service

Development and Production of Helical-Two-Step (HTS) Pipes: Grades Up to API X70 for Sour Service Application

2012 ◽  
Author(s):  
Djordje Mirković ◽  
Volker Flaxa ◽  
Franz Martin Knoop
Keyword(s):  
Low Temperature ◽  
Pipeline Steel ◽  
Steel Production ◽  
Standard Test ◽  
Pipe Production ◽  
Two Phase ◽  
Steel Grades ◽  
Low Temperature Toughness ◽  
Service Application ◽  
Sour Service

Within the corresponding commercial and R&D projects five microalloyed pipeline steel grades have recently been developed and processed to spiral-welded pipes. For steel grades X52, X65, and X70 the aimed tensile properties, improved sour service resistivity, and low temperature toughness up to −40°C were reliably achieved. Influence of steel cleanliness, the non-metallic inclusions in particular, on sour gas resistibility has been investigated by means of ultrasonic testing of hydrogen charged HIC (Hydrogen Induced Cracking) samples and SEM (Scanning Electron Microscope) analyses of HIC fracture surfaces. The results have been used to optimize the applied process parameter in steel production and coil processing. The ladle metallurgical treatment and soft reduction were consistently applied within narrow process tolerances enabling high steel cleanness and slab centerline quality, which are both indispensable for sour service application. Subsequent TMCP (Thermo Mechanical Processing) wide strip hot rolling and cooling parameters were selected to prevent a two-phase finish rolling and to obtain a predominating acicular ferritic microstructure. For pipe production, attention was paid to minimize the residual stresses, due to both pipe-forming and welding. The alloying approach is based on the classical sour lean NbTi steel composition, modified by varying Cu, Ni, Cr, and Mo contents to achieve the targeted specification. The processed spiral-welded pipes were formed to diameters between 762 and 1372 mm with a wall thickness of 13.7 to 16.0 mm. CVN (Charpy V-Notch) values were higher than 360 J/cm2 and DWTT (Drop Weight Tear Test) higher than 60% SA (Shear Area) at −40°C. The samples also showed outstanding HIC resistivity. Being proved with standard test conditions according to NACE TM0284 solution A, the CAR (Crack Area Ratio) average value of pipe samples was less than 1% for grades up to X65 and less than 5% for X70 grades. The 4-point-bending SSC (Sulphide Stress Cracking) tests at 80% of SMYS according to NACE TM0177 and ASTM G39 showed no SSC cracks for all projects. Finally, the results of one specific R&D project are presented to demonstrate that even for API X70 grade spiral-welded pipes (OD 1016×16 mm) mechanical properties, e.g. high-strength, ductility, and low temperature toughness has been successfully combined with sour service resistivity.

Effects of Finish Cooling Temperature on Microstructure and Properties of X100 Pipeline Steels

2016 ◽  
Vol 850 ◽  
pp. 993-999
Author(s):  
Shu Jun Jia ◽  
Qing You Liu ◽  
Ba Li ◽  
Hong Mei Hao
Keyword(s):  
Volume Fraction ◽  
Pipeline Steel ◽  
Steel Production ◽  
Mechanical Tests ◽  
Yield Ratio ◽  
Pipeline Steels ◽  
Cooling Temperature ◽  
Key Factor ◽  
X100 Pipeline Steel ◽  
Peak Value

The effect of finish cooling temperature on microstructure and mechanical properties of X100 pipeline steels were investigated through SEM, TEM and mechanical tests. The results showed that the effect of finish cooling temperature on tensile strength of studied steels were slight in the temperature range of 180°C~500°C. The yield ratio, yield strength and impact toughness all presented peak value when the finish cooling temperature was 360°C, however, both the volume fraction and particle size of MA component at 360°C finish cooling temperature had the minimum values. As a brittle hardening phase in bainite the increased number and enlarged size of the MA component were the key factor of the decrease of the yield ratio and toughness. Therefore, rational choosing finish cooling temperature could optimize the morphology and distribution of MA component to make sure the required strength and toughness for the X100 pipeline steel production.

Sign in / Sign up

Export Citation Format

Share Document