Metallurgical Design and Development of High Deformable X100 Line Pipe Steels Suitable for Strain-Based Design

2008 ◽  
Author(s):  
Takuya Hara ◽  
Yoshio Terada ◽  
Yasuhiro Shinohara ◽  
Hitoshi Asahi ◽  
Naoki Doi
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Pipe Material ◽  
Pipe Steels ◽  
Design And Development ◽  
Long Distance ◽  
Line Pipe ◽  
The World ◽  
Low Temperature Toughness ◽  
Transmission Pipelines

The demand for natural gas using pipelines and LNG to supply the world gas markets is increasing substituting for oil and coal. The use of high strength line pipe steels provides the reduction of cost of gas transmission pipelines by enabling high-pressure transmission of large volumes of gas. In particular, high strength line pipe materials with a yield strength of X80 or higher have been developed over the last few decades around the world. Long distance gas transmission pipelines from remote areas sometimes pass through discontinuous permafrost, and are subject to ground movements by repeated thaw subsidence and frost heave. In this case, strain-based design has been applied as well as stress-based design. Therefore, high deformable line pipe is required for strain-based design in order to prevent the pipeline from fracturing. Nippon steel has also developed high deformable high strength line pipe material suitable for strain-based design. In recent years, demand for high strength line pipe steels has emerged in which the molybdenum content is reduced because of the high cost of molybdenum. Conventionally, high strength line pipe steel with Mo addition has been developed in order to control the microstructure and to obtain pipe properties such as strength and low temperature toughness. This paper describes the metallurgical design and development of high deformable high strength X100 line pipe with lower Mo content suitable for strain-based design. High deformable X100 line pipe with 16 mm wall thickness as well as good low temperature toughness and seam weld toughness has been developed.

Metallurgical Design and Development of High-Grade Line Pipe

2012 ◽  
Author(s):  
Takuya Hara ◽  
Taishi Fujishiro ◽  
Yasuhiro Shinohara ◽  
Eiji Tsuru ◽  
Naoki Doi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Low Temperature ◽  
Cost Savings ◽  
High Strength ◽  
Design And Development ◽  
Line Pipe ◽  
Good Balance ◽  
Low Temperature Toughness ◽  
And Control ◽  
High Deformability

The application of high-strength line pipes has enabled pipelines to operate at high pressure, generating cost savings for both gas transportation and construction. In general, high-strength line pipes require crack initiation resistance and crack arrestability at low temperatures, as well as field weldability. High strength and deformability for strain-based design and excellent sour resistance are also required. Moreover, composite properties are often required for high-strength line pipes. This paper describes our progress in this field with regard to metallurgical design and development. Metallurgical design aimed at achieving a good balance between strength, low temperature toughness and deformability for strain-based design is also described from the perspectives of grain refinement, microstructure and chemical composition. Metallurgical design focused on a good balance between strength and sour resistance in limited low chemical composition is described from the perspectives of microstructure and control to chemical composition and center segregation. These efforts have led to the development of high-strength heavy wall line pipes of API X60 to X100 grades offering excellent low temperature toughness and high deformability for stain-based design, while API grades X65 to X70 with good sour resistance have also been developed.

Development of Heavy Gauge X70 Helical Line Pipe

2018 ◽  
Author(s):  
L. E. Collins ◽  
K. Dunnett ◽  
T. Hylton ◽  
A. Ray
Keyword(s):  
Low Temperature ◽  
Large Diameter ◽  
High Strength ◽  
Helical Line ◽  
Slab Thickness ◽  
Long Distance ◽  
Austenite Grain Size ◽  
Line Pipe ◽  
Nitrogen Levels ◽  
Low Temperature Toughness

A decade ago, the pipeline industry was actively exploring the use of high strength steels (X80 and greater) for long distance, large diameter pipelines operating at high pressures. However in recent years the industry has adopted a more conservative approach preferring to utilize well established X70 grade pipe in heavier wall thicknesses to accommodate the demand for increased operating pressures. In order to meet this demand, EVRAZ has undertaken a substantial upgrade of both its steelmaking and helical pipemaking facilities. The EVRAZ process is relatively unique employing electric arc furnace (EAF) steelmaking to melt scrap, coupled with Steckel mill rolling for the production of coil which is fed into helical DSAW pipe mills for the production of large diameter line pipe in lengths up to 80 feet. Prior to the upgrade production had been limited to a maximum finished wall thickness of ∼17 mm. The upgrades have included installation of vacuum de-gassing to reduce hydrogen and nitrogen levels, upgrading the caster to improve cast steel quality and allow production of thicker (250 mm) slabs, upgrades to the power trains on the mill stands to achieve greater rolling reductions, replacement of the laminar flow cooling system after rolling and installation of a downcoiler capable of coiling 25.4 mm X70 material. As well a new helical DSAW mill has been installed which is capable of producing large diameter pipe in thicknesses up to 25.4 mm. The installation of the equipment has provided both opportunities and challenges. Specific initiatives have sought to produce X70 line pipe in thicknesses up to 25.4 mm, improve low temperature toughness and expand the range of sour service grades available. This paper will focus on alloy design and rolling strategies to achieve high strength coupled with low temperature toughness. The role of improved centerline segregation control will be examined. The use of scrap as a feedstock to the EAF process results in relatively high nitrogen contents compared to blast furnace (BOF) operations. While nitrogen can be reduced to some extent by vacuum de-gassing, rolling practices must be designed to accommodate nitrogen levels of 60 ppm. Greater slab thickness allows greater total reduction, but heat removal considerations must be addressed in optimization of rolling schedules to achieve suitable microstructures to achieve both strength and toughness. This optimization requires definition of the reductions to be accomplished during roughing (recrystallization rolling to achieve a fine uniform austenite grain size) and finishing (pancaking to produce heavily deformed austenite) and specification of cooling rates and coiling temperatures subsequent to rolling to obtain suitable transformation microstructures. The successful process development will be discussed.

Development of X80M Line Pipe Steel for Spiral Welded Pipes With Low Temperature Toughness and Excellent Weldability

2014 ◽  
Author(s):  
Nuria Sanchez ◽  
Özlem E. Güngör ◽  
Martin Liebeherr ◽  
Nenad Ilić
Keyword(s):  
Low Temperature ◽  
Life Cycle Cost ◽  
Volume Fraction ◽  
Large Diameter ◽  
Pipe Production ◽  
Strain Accumulation ◽  
Long Distance ◽  
Line Pipe ◽  
Low Temperature Toughness ◽  
Welded Pipe

The unique combination of high strength and low temperature toughness on heavy wall thickness coils allows higher operating pressures in large diameter spiral welded pipes and could represent a 10% reduction in life cycle cost on long distance gas pipe lines. One of the current processing routes for these high thickness grades is the thermo-mechanical controlled processing (TMCP) route, which critically depends on the austenite conditioning during hot forming at specific temperature in relation to the aimed metallurgical mechanisms (recrystallization, strain accumulation, phase transformation). Detailed mechanical and microstructural characterization on selected coils and pipes corresponding to the X80M grade in 24 mm thickness reveals that effective grain size and distribution together with the through thickness gradient are key parameters to control in order to ensure the adequate toughness of the material. Studies on the softening behavior revealed that the grain coarsening in the mid-thickness is related to a decrease of strain accumulation during hot rolling. It was also observed a toughness detrimental effect with the increment of the volume fraction of M/A (martensite/retained austenite) in the middle thickness of the coils, related to the cooling practice. Finally, submerged arc weldability for spiral welded pipe manufacturing was evaluated on coil skelp in 24 mm thickness. The investigations revealed the suitability of the material for spiral welded pipe production, preserving the tensile properties and maintaining acceptable toughness values in the heat-affected zone. The present study revealed that the adequate chemical alloying selection and processing control provide enhanced low temperature toughness on pipes with excellent weldability formed from hot rolled coils X80 grade in 24 mm thickness produced at ArcelorMittal Bremen.

IN-787

Alloy Digest ◽  
1973 ◽  
Vol 22 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Atmospheric Corrosion ◽  
High Strength ◽  
Heat Treating ◽  
Line Pipe ◽  
International Nickel Company ◽  
Pipe Welding ◽  
Low Temperature Toughness

Abstract IN-787 is an age-hardenable, high-strength structural steel. It is characterized by low-temperature toughness, good atmospheric corrosion resistance and excellent weldability, even under adverse field conditions such as line-pipe welding. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-286. Producer or source: International Nickel Company Inc..

Research and Development of Deep-Sea Pipeline Steel

2010 ◽  
Vol 152-153 ◽  
pp. 1492-1498
Author(s):  
Jin Qiao Xu ◽  
Bin Guo ◽  
Lin Zheng ◽  
Yin Hua Li ◽  
Le Yu
Keyword(s):  
Low Temperature ◽  
Deep Sea ◽  
Pipeline Steel ◽  
High Strength ◽  
Steel Company ◽  
Line Pipe ◽  
Iron And Steel ◽  
Company Group ◽  
Pipeline Project ◽  
Low Temperature Toughness

This paper provides a detailed description of deep-sea pipeline steel developed at Wuhan Iron and Steel Company(Group), WISCO for short. The thickness of the trial produced plates is 28mm. The chemical composition of low C-high Mn-Nb-Ti with proper content of other alloys and thermo-mechanical controlled process were applied. The results show that the deep-sea pipeline steel developed at Wuhan Iron and Steel Company has a good match of high strength, low temperature toughness and excellent deformability with fine uniform microstructure. The LSAW line pipe manufactured by JCOE method has high strength, good low temperature toughness and low yield ratio which comprehensively meet the requirements of the South China Sea Liwan pipeline project.

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.

Microstructure Identification for X80 Plates/Pipes With Low Temperature Toughness and Enhanced Strain Capacity

2014 ◽  
Author(s):  
Andrea Di Schino ◽  
Lei Zheng ◽  
Chuanguo Zhang ◽  
Giorgio Porcu
Keyword(s):  
Chemical Composition ◽  
Low Temperature ◽  
Ground Movement ◽  
Pipe Material ◽  
Cooling Process ◽  
Long Distance ◽  
Strain Capacity ◽  
Enhanced Strain ◽  
Low Temperature Toughness ◽  
Test Materials

Due to the increasing demand for natural gas, the construction of long-distance pipelines through seismically active regions or arctic regions with ground movement caused by permafrost phenomena will become more and more necessary. To guarantee the safe operation of those pipelines, the pipe material has to fulfil strain-based design requirements. Hence in longitudinal direction low yield-to-tensile ratios, high uniform elongation values and a roundhouse shape of the stress-strain curve combined with sufficient strength values in transverse direction are essential. Moreover, a satisfactory low temperature toughness has to be guaranteed. An adequate plate metallurgical design is fundamental for appropriate pipe properties achievement. As far as concerns the plate design the understanding and the control of microstructure are the key factors, achieved by an adequate steel chemical composition and proper process parameters. In the framework of a co-operation between Baosteel and Centro Sviluppo Materiali (CSM), a project has been started aimed at manufacturing X80 strain based designed pipes. As a starting point pilot trials have been carried out at Baosteel Research Center in order to produce different microstructures. Besides the steel chemical composition, the cooling process has the most significant influence on the formation of the microstructure: in order to assess the effect of the cooling process, the same rolling schedule was adopted for producing the different test materials, obtained varying the start cooling and finish cooling temperatures. The microstructure and mechanical properties of the different test materials were assessed and the best microstructure for the plates for X80 pipes with enhanced strain capacity has been identified.

Application of B-Added Low Carbon Bainite Steels to X80 UOE Line Pipe for Ultra Low Temperature Usage

2010 ◽  
Author(s):  
Taishi Fujishiro ◽  
Takuya Hara ◽  
Yoshio Terada ◽  
Shinya Sakamoto ◽  
Hitoshi Asahi
Keyword(s):  
Low Temperature ◽  
Base Metal ◽  
High Strength ◽  
American Petroleum Institute ◽  
Manufacturing Cost ◽  
Chemical Compositions ◽  
Low Carbon ◽  
Line Pipe ◽  
Low Temperature Toughness ◽  
Low Carbon Bainite

Demand for high strength line pipes is increasing because of the reduction in natural gas transportation costs of pipelines. Low temperature toughness is required for high strength line pipes. Reduction in manufacturing cost of high strength linepipes is also required in an environment where alloying cost is increasing. To meet these requirements, boron (B) addition is extremely useful because the addition of very small amounts of B remarkably improves the strength and low temperature toughness. B-added low carbon bainite (LCB) line pipes with American Petroleum Institute (API) grade X60 to X80 have been developed for several decades [1–2]. B-added LCB steels have excellent low temperature toughness, however, it is challenging to achieve excellent crack initiation resistance and crack arrestability for ultra low temperatures such as −60°C. In particular, it is very difficult to achieve both excellent Drop Weight Tear Test (DWTT) properties of base metal, and excellent Charpy V-Notched (CVN) properties of seam welds in heavier wall thickness of X80 UOE linepipe. Metallurgical concepts such as the optimum chemical compositions, Thermo Mechanical Control Process (TMCP) conditions and seam weld conditions of B-added LCB steels with API grade X80 for ultra low temperature have been proposed in order to achieve the excellent mechanical properties even in a low manufacturing cost. Based on this concept, excellent DWTT properties of base metal and CVN properties of the seam welds of API grade X80 line pipe with 25mm thickness down to –60°C were obtained.

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