Modern High Strength Steels for Oil and Gas Transmission Pipelines

2008 ◽  
Author(s):  
Fulvio Siciliano ◽  
Douglas G. Stalheim ◽  
J. Malcolm Gray
Keyword(s):  
Acicular Ferrite ◽  
Oil And Gas ◽  
High Strength Steels ◽  
High Strength ◽  
Alloy System ◽  
Alloy Design ◽  
Nb Content ◽  
Transmission Pipeline ◽  
Rolling Temperatures ◽  
Transmission Pipelines

Increasing world demand for energy has resulted in plans to expand the oil and gas transmission pipeline infrastructure in many countries utilizing higher strength steels of API grade X70 and X80. Traditional transmission pipeline steels, up to grade X70, relied on a ferrite/pearlite microstructural design generated through traditional TMCP rolling of a niobium microalloyed C-Mn steel design. Increasing strengths up to X70 and X80 for transmission pipelines has resulted in a shift toward a ferrite/acicular ferrite microstructure designs. Traditionally, to generate the ferrite/acicular ferrite microstructure design for X70 or X80, TMCP rolling is applied to a C-Mn-Si-Mo-Nb alloy system. The Nb content is typically less than 0.070% in this alloy system. With the rising cost of alloys over the past three years, steel and pipe producers have been working with different alloy designs to reduce total costs to produce the ferrite/acicular ferrite microstructure. In recent developments it has been determined that an optimized low-C-Mn-Si-Cr-Nb alloy design (usually referred as NbCr steel), utilizing an Nb content between 0.080 – 0.11% can produce the same ferrite/acicular ferrite microstructure with either no, or minimal, use of molybdenum. This approach has been successfully used in several transmission pipeline projects such as the Cantarell, Cheyenne Plains and Rockies Express. Recognizing the success of previous projects around the world, the large ∼ 4500 Km 2nd West-East Pipeline Project specification in China has been modified to allow for the use of this NbCr design for both plate and coil for conversion to long seam or spiral pipe. The NbCr design allows the steel producer to utilize niobium’s unique ability to retard recrystallization at higher than normal TMCP rolling temperatures, hence the term for the alloy design High Temperature Processing (HTP), producing the desired ferrite/acicular ferrite microstructure with excellent strength, toughness and weldability. This paper will discuss the technical background, rolling strategy, mechanical properties, welding, specific projects, and specification modifications with practical examples.

The Role of Niobium in High Strength Oil and Gas Transmission Linepipe Steels

2006 ◽  
Author(s):  
Douglas G. Stalheim ◽  
Steven G. Jansto
Keyword(s):  
Low Temperature ◽  
Oil And Gas ◽  
Elevated Temperatures ◽  
Operating Cost ◽  
High Strength ◽  
Processing Technique ◽  
Alloy Design ◽  
Transmission Pipeline ◽  
Low Temperature Toughness ◽  
Transmission Pipelines

Niobium’s role in the production of oil and gas transmission pipelines steels has gained significant importance in recent years. The economical movement of gas and oil to the marketplace from remote and rugged locations requires transmission pipelines to be designed to operate at higher pressures with improved toughness over a variety of temperature ranges. With the increased demand for energy resources continuing to grow, traditional plate mills, hot strip mills along with Steckel mills around the world are processing skelp for API pipe. The capabilities of these mills can be quite varied. Consequently, a variety of operational considerations and practices have put additional focus on Nb for its ability to retard recrystallization at elevated temperatures. This ability has added a new form of processing skelp for API pipe called High Temperature Processing or HTP. This new use of Nb in higher strength API oil and gas transmission pipeline steels allows a producer to create a ferrite/acicular ferrite microstructure without the traditional molybdenum alloy based design. The HTP Nb microalloy approach has benefits including reduced operating cost per ton, ease of rolling and welding, excellent low temperature toughness properties and high strength. This processing technique for API X70 and X80 is gaining acceptance as major pipeline projects are now applying this technology. In addition, X100 properties have been achieved with a combination of the traditional X80 alloy design and the newer employed HTP alloy design. This paper will discuss Nb’s role in meeting the increased strength requirements related to operating at higher pressures, improved low temperature toughness (TCVN > 200 J@−40 °C), microstructural demands and processing capability improvements for traditional plate, strip, and Steckel mill technology. The use of the new HTP concept in high strength API production will also be introduced.

Recent Developments of Oil and Gas Transmission Pipeline Steels: Microstructure, Mechanical Properties and Sour Gas Resistance

2008 ◽  
Author(s):  
Navid Pourkia ◽  
Morteza Abedini
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Oil And Gas ◽  
High Strength ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Pipeline Steels ◽  
Bainitic Microstructure ◽  
Transmission Pipeline ◽  
Sour Gas

In modern oil and gas transmission pipeline steels technology, a suitable microstructure is an important factor for improvement of strength, toughness and sour gas resistance. Therefore, thermo-mechanically controlled rolling processes have been developed and their microstructures have been changed from ferrite-pearlite to acicular ferrite. Moreover in the recent years extensive attempts have been made to improve pipeline steels properties, which include: i) Ultra fine-grained steels, which are produced by optimized usage of dynamic recrystallization and strain-induced transformation with about 1μm equiaxed ferrite grain size. ii) Ultra low carbon steels with less than 0.025 wt% carbon and significant amount of Mo and Nb microalloying elements. iii) Ultra fine acicular ferrite steels, which are produced by application of more accurate controlled thermo mechanical processes and accelerated cooling. iv) Ultra high strength X100 and X120 grade steels, which are produced by thermo-mechanically controlled processes and heavy accelerated cooling. The former is without special technological changes and mainly consist of low carbon upper bainitic microstructure while the latter needs more technological developments with very little amount of boron and mainly consists of lower bainitic microstructure. This paper gives an overview of these new pipeline steels in viewpoint of microstructure, mechanical properties and sour gas resistance. The studies show that ultra fine acicular ferrite is the best alternative microstructure for nowadays ordinary pipeline steels, but because of numerous advantages of ultra high strength pipelines steels which finally reduce the cost of pipeline projects, the trend of the investigations is focused on further development of these steels. Moreover, acicular ferrite microstructure which is generally accepted by pipeline engineers and it is just in doubt because of its differences with acicular ferrite microstructure of weld metal and numerous offered definitions, is completely described.

When Metals and Microbes Meet: Preventing Microbial Corrosion in Crude Oil Transmission Pipelines

2020 ◽  
Author(s):  
Lisa M. Gieg ◽  
Mohita Sharma ◽  
Trevor Place ◽  
Jennifer Sargent ◽  
Yin Shen
Keyword(s):  
Crude Oil ◽  
Oil And Gas ◽  
Combined Treatment ◽  
Oil And Gas Industry ◽  
Test Methods ◽  
Microbial Corrosion ◽  
Gas Industry ◽  
Chemical Treatments ◽  
Transmission Pipeline ◽  
Transmission Pipelines

Abstract Corrosion of carbon steel infrastructure in the oil and gas industry can occur via a variety of chemical, physical, and/or microbiological mechanisms. Although microbial corrosion is known to lead to infrastructure failure in many upstream and downstream operations, predicting when and how microorganisms attack metal surfaces remains a challenge. In crude oil transmission pipelines, a kind of aggressive corrosion known as under deposit corrosion (UDC) can occur, wherein mixtures of solids (sands, clays, inorganic minerals), water, oily hydrocarbons, and microorganisms form discreet, (bio)corrosive sludges on the metal surface. To prevent UDC, operators will use physical cleaning methods (e.g., pigging) combined with chemical treatments such as biocides, corrosion inhibitors, and/or biodispersants. As such, it necessary to evaluate the efficacy of these treatments in preventing UDC by monitoring the sludge characteristics and the microorganisms that are potentially involved in the corrosion process. The efficacies of a biocide, corrosion inhibitor, and biodispersant being used to prevent microbial corrosion in a crude oil transmission pipeline were evaluated. A combination of various microbiological analyses and corrosivity tests were performed using sludge samples collected during pigging operations. The results indicated that the combined treatment using inhibitor, biocide 1 and biodispersant was the most effective in preventing metal damage, and both growth-based and Next-Generation Sequencing approaches provided value towards understanding the effects of the chemical treatments. The efficacy of a different biocide (#2) could be discriminated using these test methods. The results of this study demonstrate the importance of considering and monitoring for microbial corrosion of crucial metal infrastructure in the oil and gas industry, and the value of combining multiple lines of evidence to evaluate the performance of different chemical treatment scenarios.

Development of Low Carbon Microalloyed Ultra High Strength Steels

2005 ◽  
Vol 500-501 ◽  
pp. 551-558 ◽  
Author(s):  
A. Ghosh ◽  
Brajendra Mishra ◽  
Subrata Chatterjee
Keyword(s):  
Room Temperature ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Hsla Steels ◽  
Finish Rolling ◽  
Ultra High Strength Steels ◽  
Rolling Temperatures ◽  
Carbon Microalloyed ◽  
Carbon Concentrations

In the present study HSLA steels of varying carbon concentrations, alloyed with Mn, Ni, Cr, Mo, Cu and micro-alloyed with Nb and Ti were subjected to different finish rolling temperatures from 850oC to 750oC in steps of 50oC. The microstructure of the steel predominantly shows martensite. Fine twins, strain induced precipitates in the martensite lath along with e-Cu precipitates are observed in the microstructure. With an increase in carbon content the strength value increases from 1200MPa UTS to 1700MPa UTS with a negligible reduction in elongation. Impact toughness values of 20-26 joules at room temperature and −40oC were obtained in sub-size samples.

scholarly journals Modelling of Sub-Sea Gas Transmission Pipeline to Predict Insulation Failure

2018 ◽  
Vol 11 (1) ◽  
pp. 67-83 ◽  
Author(s):  
Ode Samson Chinedu ◽  
Okoro Emeka Emmanuel ◽  
Ekeinde Evelyn Bose ◽  
Dosunmu Adewale
Keyword(s):  
Transmission Line ◽  
Oil And Gas ◽  
New Technology ◽  
Normal Operation ◽  
Distributed Temperature Sensing ◽  
Transmission Systems ◽  
Insulation Failure ◽  
Transmission Pipeline ◽  
Optic Fibre ◽  
Transmission Pipelines

Background: Thermally insulated subsea production and transmission systems are becoming more common in deep-water/ offshore operations. Premature failures of the insulation materials for these gas transmission pipelines have had significant operational impacts. The ability to timely detect these failures within these systems has been a very difficult task for the oil and gas industries. Thus, periodic survey of the subsea transmission systems is the present practice. In addition, a new technology called optic-fibre Distributed Temperature Sensing system (DTS) is now being used to monitor subsea transmission pipeline temperatures; but this technology is rather very expensive. Objective: However, this study proposed a model which will not only predict premature insulation failure in these transmission pipelines; but will also predict the section of the transmission line where the failure had occurred. Methods: From this study, we deduced that in gas pipeline flow, exit temperature for the system increases exponentially with the distance of insulation failure and approaches the normal operation if the failure occurs towards the exit of the gas pipe. This model can also be used to check the readings of an optic-fibre distributed temperature sensors. Result and Conclusion: After developing this model using classical visual basic and excel package, the model was validated by cross plotting the normal temperature profiles of the model and field data; and R-factor of 0.967 was obtained. Analysis of the results obtained from the model showed that insulation failure in subsea gas transmission pipeline can be predicted on a real-time basis by mere reading of the arrival temperature of a gas transmission line.

Development of the SAW Wire for High Strength TMCP Steel

2005 ◽  
Vol 475-479 ◽  
pp. 269-272
Author(s):  
Xiao Huai Xue ◽  
Song Nian Lou ◽  
Bainian Qian ◽  
Shaofei Yu
Keyword(s):  
Acicular Ferrite ◽  
High Strength ◽  
Alloy System ◽  
Carbon Equivalent ◽  
Low Carbon ◽  
Key Factors ◽  
Mixture Ratio ◽  
Mn Content ◽  
Nitrogen Contents ◽  
Submerged Arc

The wire for high strength and toughness TMCP steels of submerged arc welding was developed. The low carbon and micro-alloying with Ti-B system was adopted to obtain the acicular ferrite dominated deposited metals. Experimental results show that the carbon equivalent (Pcm) should be higher than 0.17, which can ensure the high strength and high toughness of the deposited metals. In the alloy system, Oxygen and Nitrogen contents, micro-alloyed elements (C, Mn) and its mixture ratio are the key factors that affect the deposited metals toughness. With increasing C, Mn content, the acicular ferrite is increased and toughness is improved. Oxygen and Nitrogen are deleterious to the toughness of deposited metals.

Genetic Alloy Design of Ultra High Strength Stainless Steels: From Thermodynamics to Quantum Mechanics

2010 ◽  
Vol 638-642 ◽  
pp. 3473-3478
Author(s):  
Pedro E.J. Rivera-Díaz-del-Castillo ◽  
Wei Xu ◽  
Sybrand van der Zwaag
Keyword(s):  
Stainless Steels ◽  
Lath Martensite ◽  
High Strength Steels ◽  
High Strength ◽  
Alloy Design ◽  
Processing Route ◽  
Cohesion Energy ◽  
Aerospace Applications ◽  
Ultra High Strength Steels ◽  
Corrosive Environments

The design of novel ultra high strength steels for aerospace applications is subjected to stringent requirements to ensure their performance. Such requirements include the ability to withstand high loads in corrosive environments subjected to temperature variations and cyclic loading. Achieving the desired performance demands microstructural control at various scales; e.g. fine lath martensite is desired in combination with nanoprecipitate networks at specified volume fractions, and controlled concentrations of alloying elements to prevent alloy embrittlement. The design for a specified microstructure cannot be separated from the processing route required for its fabrication. Alloys displaying exceptional properties are subjected to complex interactions between microstructure and processing requirements, which can be described in terms of evolutionary principles. The present work shows how genetic alloy design principles have been utilised for designing stainless steels displaying strength exceeding that of commercial counterparts. Such designed alloys become feasible for fabrication by tailoring their microstructure employing thermodynamic and kinetic principles, while fracture toughness properties can be controlled via performing quantum mechanical cohesion energy computations.

Development of Economic-Type X70 Linepipe Steel Hot Strip

2013 ◽  
Vol 750-752 ◽  
pp. 446-449
Author(s):  
Hong Mei Yang
Keyword(s):  
Low Temperature ◽  
Acicular Ferrite ◽  
Production Cost ◽  
Pipeline Steel ◽  
High Strength ◽  
Alloy System ◽  
Hot Strip ◽  
Low Temperature Toughness ◽  
Linepipe Steel ◽  
Cost Economic

In order to reduce the production cost, economic-type X70 pipeline steels with the thickness of 14.6 and 15.9mm were redesigned . The latest alloy system of pipeline steel designed by non-molybdenum C-Mn-Cr-Nb alloy system, which replaces the high-molybdenum C-Mn-Mo-Nb alloy system, was adopted along with acicular ferrite microstructure. The microstructure of X70 strip is homogeneous and ferrite grains are fine, resulting in high strength, excellent low-temperature toughness and weldability.

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