High Strength Heavy Plate Optimised for Application in Remote Areas and Low-Temperature Service

2010 ◽  
Author(s):  
Charles Stallybrass ◽  
Joachim Konrad ◽  
Heike Meuser ◽  
Fabian Grimpe
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
High Strength ◽  
Alternative Methods ◽  
Accelerated Cooling ◽  
Processing Conditions ◽  
Remote Areas ◽  
Heavy Plate ◽  
Low Temperature Toughness ◽  
Ebsd Method

The last decades have seen a steady increase in the demand for high-strength linepipe steels. These offer the most economical option to transport large gas volumes at high pressures from remote areas to the market. Since the beginning of the 1980’s, high strength heavy plates, pipes and pipe bends were developed and produced at Salzgitter Mannesmann Grobblech GmbH and EUROPIPE. Since these days, these products were steadily improved for example in terms of toughness and weldability. As gas resources in increasingly hostile environments are developed, the requirements with regard to deformability and low-temperature toughness have gained growing significance. This is a strong focus of materials development around the world. Modern high-strength heavy plates used in the production of UOE pipes are generally produced by thermomechanical rolling followed by accelerated cooling (TMCP). If accelerated cooling starts above the ferrite-austenite transformation temperature, this processing route results in a microstructure that consists predominantly of bainite. The combination of high strength and high toughness of these steels are a result of the microstructure realised by TMCP and are strongly influenced by the rolling and cooling conditions. Classical light-optical characterisation of the microstructure of these steels is at its limits because the size of the observed features is too small to allow reliable quantitative results. Therefore alternative methods have to be used to obtain a better understanding of the influence of processing conditions on the microstructure. The mechanical properties of high strength plates produced at Salzgitter Mannesmann Grobblech (MGB) and of material rolled using a laboratory rolling mill at the Salzgitter Mannesmann Forschung (SZMF) was characterised with special emphasis on low-temperature toughness. The microstructure was investigated using the electron backscatter diffraction (EBSD) method. With this method, it is possible to gain quantitative information related to features of the microstructure and relate these to the mechanical properties of the plate material. It was found that a variation of the processing conditions has a direct influence on parameters that are accessible through the EBSD method and correlates with mechanical properties. These results can be used as valuable input for the definition of the processing window for heavy plate production depending on the required plate properties.

Development of Modern High Strength Heavy Plates for Linepipe Applications

2012 ◽  
Author(s):  
Heike Meuser ◽  
Florian Gerdemann ◽  
Fabian Grimpe ◽  
Charles Stallybrass
Keyword(s):  
Mechanical Properties ◽  
High Pressures ◽  
Large Diameter ◽  
High Strength ◽  
Alternative Methods ◽  
Accelerated Cooling ◽  
Processing Conditions ◽  
Line Pipe ◽  
Heavy Plate ◽  
Shear Area

High strength linepipe steels have to fulfil increasing property demands in modern pipeline applications. The transport of large gas volumes at high pressures from remote areas to the market is achieved in the most economical way by large diameter pipelines. For the last 30 years, high strength heavy plates for pipes and pipe bends were developed and produced at Salzgitter Mannesmann Grobblech. These products were steadily improved for example in terms of toughness and fracture behaviour at low temperatures. This is a strong focus of materials development around the world. Modern high-strength heavy plates used in the production of UOE pipes are generally produced by thermomechanical rolling followed by accelerated cooling (TMCP). The combination of high strength and high toughness of these steels is a result of the bainitic microstructure realised by TMCP and are strongly influenced by the rolling and cooling conditions. This paper gives an overview of the development of high strength plates for line pipe application at Salzgitter Mannesmann Grobblech. From comparably thin-walled X80 plates with no or medium DWTT requirements to recent requirements for approx. 28 mm thick X80 plates with requirements of 75/85% shear area fraction at −30°C and more than 250 J Charpy energy at −40°C the development work and the result of the last five years are described and presented. Classical light-optical characterisation of the microstructure of these steels is at its limits because the size of the observed features is too small to allow reliable quantitative results. Therefore Salzgitter Mannesmann Grobblech and Salzgitter Mannesmann Forschung (SZMF) developed alternative methods with the aim of a quantification of microstructure features and a correlation of those with the mechanical properties and processing conditions. In several investigations, the information is related to the mechanical properties of the plate material. It was found that a variation of the processing conditions has a direct influence on parameters that are accessible through the EBSD method and correlates with mechanical properties. The detailed correlations vary depending on steel grade and TMCP strategy. The results have to be carefully interpreted and help understanding the connection between processing and properties. Consequently this can be used as valuable input for the definition of the processing window for heavy plate production with optimized properties.

scholarly journals Effect of Bainitic Microstructure on Low-Temperature Toughness of High-Strength API Pipeline Steels

2020 ◽  
Vol 58 (5) ◽  
pp. 293-303
Author(s):  
Seung-Wan Lee ◽  
Sang-In Lee ◽  
Byoungchul Hwang
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Crack Initiation ◽  
High Strength ◽  
Processing Conditions ◽  
Absorbed Energy ◽  
Pipeline Steels ◽  
Bainitic Microstructure ◽  
Effective Grain Size ◽  
Low Temperature Toughness

In this study the correlation between bainitic microstructure and the low-temperature toughness of high-strength API pipeline steels was discussed in terms of crack initiation and propagation in the microstructure. Three types of API pipeline steels with different bainitic microstructures were fabricated using varying alloying elements and thermo-mechanical processing conditions, and then their microstructure was characterized by optical and scanning electron microscopy, and electron backscatter diffraction (EBSD). In particular, the effective grain size and microstructure fraction of the steels were quantitatively measured by EBSD analysis. Although all the steels were composed of polygonal ferrite (PF), and complex bainitic microstructures such as acicular ferrite (AF), granular bainite (GB), and bainitic ferrite (BF), they had different effective grain sizes and microstructure fraction, depending on the alloying elements and thermomechanical processing conditions. Charpy impact test results showed that when the martensite-austenite constituent fraction was lowest, it resulted in higher upper-shelf energy, and absorbed energy at room temperature due to the decrease in crack initiation. In contrast, excellent low-temperature toughness, such as lower ductile-brittle transition temperature and higher absorbed energy at low temperatures, could be achieved with a bainitic microstructure with fine effective grain size and high fraction of high-angle grain boundaries, which act as obstacles to prevent cleavage crack propagation.

Effect of Heat Treatment Process on Microstructure and Properties of High Strength Heavy Plate for Ship Hull

2012 ◽  
Vol 630 ◽  
pp. 59-63
Author(s):  
De Cheng Wan ◽  
Qing Wu Cai ◽  
Wei Yu ◽  
Xiao Lin Li ◽  
Chang Zheng Dong
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
High Strength ◽  
Ship Hull ◽  
Heat Treatment Process ◽  
Grain Refining ◽  
Heavy Plate ◽  
Double Quenching ◽  
Low Temperature Toughness

The variation of microstructure and their effect on the mechanical properties of heavy plate for ship hull treated by quenching in full austenite region at 910°C once or twice and tempering, or quenching in full austenite region and quenching in intercritical austenite region at 840°C again and tempering were studied with SEM and TEM. It was found that the strength and low temperature toughness of the steel were higher after double quenching in full austenite region and tempering than the steel which was quenched once and tempering, because smaller bainite inter-lath spacing, finer grains were obtained. The steel treated by intercritical quenching at 840°C after quenching in full austenite region and tempering showed the best combination of mechanical properties. This can be attributed to comprehensive effect of the uniform distribution of ferrite and bainite, stronger grain refining effect caused by formation of ferrite.

Development of NbTiB Microalloyed HSLA Steels for High-Strength Heavy Plate

2005 ◽  
Vol 500-501 ◽  
pp. 565-572 ◽  
Author(s):  
H. Meuser ◽  
F. Grimpe ◽  
S. Meimeth ◽  
C.J. Heckmann ◽  
C. Träger
Keyword(s):  
High Strength ◽  
Optimum Process ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Alloying Element ◽  
Heavy Plate ◽  
Hsla Steels ◽  
Bainitic Microstructure ◽  
Bainitic Structure ◽  
Low Temperature Toughness

This paper deals with the development of low carbon NbTiB micro-alloyed high strength low alloy steel for heavy plates with high wall thickness. In the production of heavy plate it is remarkably difficult to achieve a combination of high strength and good low-temperature toughness. Bainitic microstructures have shown the capability to attain such requirements. To achieve a bainitic microstructure even for heavy wall products the formation of bainite can be promoted and supported by the use of small amounts of boron as a micro-alloying element. This industrial research project is based on the addition of small amounts of boron to promote the desired bainitic structure. Mill rolling trials were carried out to determine the optimum process parameters. The results of experimental mill rolling trials on 35 mm plates will be presented in this paper.

Graphene Oxide-Based Composite Organohydrogels with High Strength and Low Temperature Resistance for Strain Sensors

Soft Matter ◽  
2022 ◽  
Author(s):  
Rui Zhao ◽  
Li Jiang ◽  
Ping Zhang ◽  
Dan Li ◽  
Zhenzhong Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Low Temperature ◽  
Rapid Development ◽  
High Strength ◽  
Strain Sensors ◽  
Temperature Resistance ◽  
Polymeric Hydrogel ◽  
Low Temperature Resistance

In the recent years, a rapid development of the polymeric hydrogel-based sensors has been witnessed. However, conventional hydrogels often exhibit poor mechanical properties. Additionally, the use of these sensors at...

Effect of Processing Route on Mechanical Behavior of C-Mn Multiphase High Strength Cold Rolled Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4375-4380
Author(s):  
Dagoberto Brandão Santos ◽  
Élida G. Neves ◽  
Elena V. Pereloma
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Quantitative Relationship ◽  
High Strength ◽  
Microstructural Characterization ◽  
Processing Route ◽  
Accelerated Cooling ◽  
Microstructural Parameters ◽  
Transmission Electron

The multiphase steels have complex microstructures containing polygonal ferrite, martensite, bainite, carbide and a small amount of retained austenite. This microstructure provides these steels with a high mechanical strength and good ductility. Different thermal cycles were simulated in the laboratory in order to create the microstructures with improved mechanical properties. The samples were heated to various annealing temperatures (740, 760 or 780°C), held for 300 s, and then quickly cooled to 600 or 500°C, where they were soaked for another 300 s and then submitted to the accelerated cooling process, with the rates in the range of 12-30°C/s. The microstructure was examined at the end of each processing route. The mechanical behavior evaluation was made by microhardness testing. The microstructural characterization involved optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). The use of multiple regression analysis allowed the establishment of quantitative relationship between the microstructural parameters, cooling rates and mechanical properties of the steel.

Research and Development of High Strength Architectural Heavy Plates

2012 ◽  
Vol 190-191 ◽  
pp. 590-594
Author(s):  
Ming Wei Tong ◽  
Ze Xi Yuan ◽  
Kai Guang Zhang
Keyword(s):  
Low Temperature ◽  
Large Scale ◽  
High Strength ◽  
Technical Requirement ◽  
Good Match ◽  
Iron And Steel ◽  
Fracture Transition ◽  
Fine Microstructure ◽  
Low Temperature Toughness ◽  
Base Plates

This paper provides a detailed description of high strength architectural heavy plates with 80mm in thickness developed at Wuhan Iron and Steel（Group）Corporation(WISCO). The chemical composition of plates contains mainly C-Mn-Nb-V-Ti with proper content of other alloys, and the thermal-mechanical controlled process and normalizing treatment were applied. The results show that the base plates manufactured at WISCO have a good match of high strength, good through-thickness characteristic, low yield ratio and low temperature toughness with fine microstructure, and the fracture transition temperature is about -40°C. The welding plate also has high strength and good low temperature toughness which comprehensively meet the technical requirement of large-scale architectural buildings.

Development of High-Strength Steel Plates for Low-Temperature Use

1988 ◽  
Vol 110 (3) ◽  
pp. 171-176
Author(s):  
Y. Nakano ◽  
Y. Saito ◽  
K. Amano ◽  
M. Koda ◽  
Y. Sannomiya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Yield Strength ◽  
Structural Steel ◽  
Welded Joints ◽  
High Strength Steel ◽  
Control Process ◽  
Charpy Impact ◽  
High Strength ◽  
Steel Plates

This paper describes the metallurgical approaches for producing 415MPa and 460MPa yield strength offshore structural steel plates and the mechanical properties of the steel plates and their welded joints. A thermo-mechanical control process (TMCP) was adopted to manufacture YP415MPa and YP460MPa steel plates with weldability comparable to conventional YP355MPa steel plates. The Charpy impact and CTOD tests of the steel plates and their welded joints proved to be very good.

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