Process, Microstructure and Mechanical Properties of X90 Pipeline Steel

2016 ◽  
Vol 850 ◽  
pp. 894-898
Author(s):  
Bin Guo ◽  
Jin Qiao Xu ◽  
Lei Cui ◽  
Qing Feng Wang
Keyword(s):  
Mechanical Properties ◽  
Manufacturing Process ◽  
Pipeline Steel ◽  
Structural Characteristics ◽  
High Strength ◽  
Controlled Rolling ◽  
Accelerated Cooling ◽  
Iron And Steel ◽  
Technical Requirements ◽  
China National Petroleum Corporation

This paper provided a detailed description of X90 pipeline steel developed in Wuhan Iron and Steel Corporation (WISCO), including its metallurgical design, manufacturing process, structural characteristics and mechanical properties. Some key issues such as the cooling rate and rolling parameters were addressed for the development of X90 pipeline steel. The experimental results showed that the manufacturing process of controlled rolling (for austenite refining) + relaxation (for ferrite phase transformation) +ultrafast accelerated cooling could guarantee very fine microstructure and excellent mechanical properties. The X90 pipeline steel developed in WISCO has a good match of high strength and excellent toughness. Mechanical properties of X90 coils, plates and corresponding SSAW and LSAW pipes comprehensively meet the technical requirements of China National Petroleum Corporation (CNPC).

scholarly journals Study of the thermal treatment modes influence on the forming of microstructure and specified complex of mechanical properties of high-strength sheet product with guaranteed level of hardness (400–450 HB) of low-alloyed steel

2019 ◽  
Vol 75 (4) ◽  
pp. 480-487
Author(s):  
M. Yu. Matrosov ◽  
P. G. Martynov ◽  
A. V. Mitrofanov ◽  
K. Yu. Barabash ◽  
T. V. Goroshko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fine Structure ◽  
Thermal Treatment ◽  
Hot Rolling ◽  
High Strength ◽  
Controlled Rolling ◽  
Alloyed Steel ◽  
Accelerated Cooling ◽  
Cold Forming ◽  
Low Alloyed Steel

High-strength sheet product of low-alloyed steel, used at manufacturing of heavy-loaded structures, must have, apart from wear resistance, high toughness, good weldability, ability to hot and cold forming, machinability and low cost. Combination of these properties based on forming fine grain austenite structure before the martensitic transformation at definite its thermal treatment modes. Results of study of microstructure, fine structure and mechanical properties of high-strength boron-containing low-alloyed steel after different technological methods of the rolled product manufacturing presented: high-temperature hot rolling and twostages controlled rolling with accelerated cooling followed by thermal treatment – quenching with tempering. Variants of optimal modes of thermal treatment determined, providing combination of high level of impact toughness under negative temperatures, hardness and strength properties of sheet product. The two considered in the article technological variants, comprising treatment of low-alloyed steel with boron (hot rolling and two-stages controlled rolling with accelerated cooling) followed by thermal treatment results in forming fine structure of tempered martensite, which provides high mechanical properties, meeting the made requirements. Depending on the heating temperature before quenching in the range 770–950 °С, the morphology of the actual steel grain is changing from elongated to equiaxed, which is connected with the metal recrystallization process during heating after plastic deformation. The study results obtained allow to optimize the thermal treatment processes of sheet product of low-alloyed boron containing steel for particular conditions of application.

scholarly journals Effect of Cooling and Isothermal Holding on the Amount of Martensite/Austenite (M/A) Constituents, Microstructure and Mechanical Properties of Microalloyed Pipeline Steel

2018 ◽  
Vol 918 ◽  
pp. 152-158 ◽  
Author(s):  
Alexander Kabanov ◽  
Grzegorz Korpala ◽  
Rudolf Kawalla ◽  
Sergey Ionov
Keyword(s):  
Mechanical Properties ◽  
Pipeline Steel ◽  
Isothermal Holding ◽  
High Strength Steels ◽  
High Strength ◽  
Cold Climate ◽  
Throughput Capacity ◽  
Accelerated Cooling ◽  
Bainitic Steels ◽  
Strength And Plasticity

Constant increase of energy consumption in modern industry requires construction of heavily loaded pipelines with high throughput capacity. Therefore, high-strength steels should be used for the cost reasons. Additionally, the pipelines are also often used in the areas with cold climate and high seismicity. Therefore, strength and plasticity reduction is unacceptable. Bainitic steels with retained austenite (RA) or martensite/austenite (M/A) constituents meet these requirements. The purpose of this investigation is to determine thermo-mechanical treatment parameters with further accelerated cooling and additional isothermal holding for M/A-phase and mechanical properties formation. Experimental modeling of the production process was carried out using Gleeble HDS-V40 thermo-mechanical simulator. All investigations were realized with two high-strength micro-alloyed steels with different molybdenum and carbon content. Results showed that decrease of temperature and duration of isothermal holding as well as addition of molybdenum promote bainitic microstructure nucleation and reduce grain size and M/A-constituents. All these factors lead to a slight improvement in mechanical properties.

Recent Development in High Strength Linepipe for Sour Environment

2003 ◽  
Author(s):  
Nobuyuki Ishikawa ◽  
Toyohisa Shinmiya ◽  
Shigeru Endo ◽  
Tsunemi Wada ◽  
Joe Kondo
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Controlled Rolling ◽  
Accelerated Cooling ◽  
Optimum Conditions ◽  
Microstructural Characteristics ◽  
Design Concepts ◽  
Bainitic Microstructure ◽  
Linepipe Steels ◽  
Sour Gas

This paper firstly summarizes the design concepts for controlling crack resistant property and mechanical properties of high strength linepipe steels for sour gas service. Optimum conditions of controlled rolling and accelerated cooling that balances crack resistant property and toughness were investigated. It was demonstrated that higher cooling rate in accelerated cooling process brings tremendous advantages for balancing toughness and strength by fine bainitic microstructure even for heavy wall thick pipes. Production results of high strength sour resistant linepipes were introduced. In order to increase strength grade of sour linepipes, further investigation was made using the steels with different microstructures. It was found that precipitation hardened ferrite-bainite steels have extremely high resistance against HIC even for Grade X80. Mechanical properties and microstructural characteristics of this newly developed steel were introduced in this paper.

Spun Steel Pipes for the Offshore Industry

1983 ◽  
Vol 105 (1) ◽  
pp. 97-102 ◽  
Author(s):  
A. Royer ◽  
B. Dumas ◽  
M. Gantois
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Centrifugal Casting ◽  
High Strength ◽  
Controlled Rolling ◽  
Climatic Conditions ◽  
Casting Technique ◽  
Steel Pipes ◽  
Potential Applications ◽  
Offshore Industry

Many parts either for sea-line pipes as “buckle” or “crack arrestor,” or for structures may require the use of wall tubular products with high mechanical properties. Such heavy-wall pipes may be produced by centrifugal casting. Two Mn-Mo steels have been developed for medium-wall pipes (e≤35 mm) to be used under very severe climatic conditions: an acicular ferritic steel, a pearlite reduced steel produced by controlled rolling techniques [1, 2, 3]. More alloyed chemical composition and heat-treatments are needed to produce heavy-wall pipes. Then, production of such pipes is more difficult and sometimes impossible. Observations made on controlled-rolled Mn-Mo steel led to a better understanding of the influence of metallurgical structures and chemical composition on steel characteristics. Similar metallurgical structures can only be reached via other routes, for example centrifugal-casting of steel associated with heat-treatment, lead to the production of heavy-wall pipes with high strength and suitable transition temperature. After a brief description of the centrifugal casting technique, we introduce the grades developed for heavy-wall pipes with yield strength up to 100,000 psi. The mechanical properties, Battelle, fatigue, static bending, C.O.D., weldability, etc., of Centrishore II are given and compared to other materials. Possible offshore applications and other potential applications of parts produced by centrifugal casting are described.

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.

About Ultrasonic Inspection of Work Pieces and Products from Carbon-Carbon Composite Materials

NDT World ◽  
2015 ◽  
Vol 19 (4) ◽  
pp. 20-23
Author(s):  
Беркутов ◽  
Igor Berkutov ◽  
Быченок ◽  
Vladimir Bychenok ◽  
Майоров ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Production Technology ◽  
Ultrasonic Inspection ◽  
High Strength ◽  
Signal Amplitude ◽  
Carbon Composite ◽  
Shadow Method ◽  
Spectral Maximum ◽  
Velocity Signal ◽  
Technical Requirements

Introduction. Carbon-carbon composite products feature high strength at temperatures up to 3000 C, resistance to aggressive environments, mechanical reliability and relatively low density. Up to now, there are no NDT established procedures for assessing the quality of composite products and their compliance with the technical requirements. Nowadays composites know-how can not guarantee the specified requirements. The paper provides the estimation of the composites ultrasonic testing equipment and procedure. Method. Subjected to studies were samples made a) in compliance with the required production technology, b) to ensure low mechanical properties, c) to ensure wrong frame geometry. An electronic module and transducers were developed so that a shadow method of sample examination in 3 orthogonal planes could be used. Subjected to studies were samples made a) in compliance with the required production technology, b) to ensure low mechanical properties, c) to ensure wrong frame geometry. An electronic module and transducers were developed so that a shadow method of sample examination in 3 orthogonal planes could be used. Results. The paper provides an analysis of relations between ultrasonic wave propagation velocity, signal amplitude, and the spectral maximum. It has been shown that a 200-500 kHz signal is appropriate to test all available samples, whereas a 400-500 kHz signal provides more information on the product and its defects. Defective samples shift the spectrum maximum to lower frequencies which can be used as the product rejection criterion. Possible directions in the further studies to improve the measurement accuracy have been emphasized. Conclusions. The findings show good opening for the carbon-carbon composites acoustic NDT.

Microstructure and Mechanical Properties of Twinning M/A Islands in a X100 High Strength Pipeline Steel

2017 ◽  
Vol 896 ◽  
pp. 182-189 ◽  
Author(s):  
Ji Ming Zhang ◽  
Qiang Chi ◽  
Ling Kang Ji ◽  
Hui Feng ◽  
Yan Hua Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
High Strength ◽  
Pipeline Steels ◽  
Transmission Electron ◽  
Fine Microstructure ◽  
X100 Pipeline Steel ◽  
Deformation Hardening

Fine microstructure of twinning Martensite/austenite (M/A) islands in a X100 high strength pipeline steel were analyzed by the scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM), and a uniaxial compressive experiment of micro-pillar for a twinning M/A island was conducted in present paper. The experimental results showed that M/A islands in X100 pipeline steels were consisted of retained austenite and nanoscale twins with sizes of less than ten nanometers. There were a few small blocks of nanoscale twins in an M/A island. Volume fraction of twinning M/A islands had an important effect on mechanical properties of X100 pipeline steels, with the increase of twinning M/A islands fraction, yield strength of X100 pipeline steel increased, and impact toughness of X100 pipeline steel decreased. The micro-pillar compression showed that the nanoscale twinning M/A island exhibited the higher deformation hardening during the compressive test, and its uniaxial compressive strength could up to 1.35GPa ultrahigh stress level.

Microstructural, surface and fatigue analysis of stress peened leaf springs

2015 ◽  
Vol 6 (5) ◽  
pp. 589-604 ◽  
Author(s):  
Georgios Savaidis ◽  
Stylianos Karditsas ◽  
Alexander Savaidis ◽  
Roselita Fragoudakis
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fatigue Life ◽  
Manufacturing Process ◽  
Treatment Process ◽  
High Strength ◽  
Content Type ◽  
Leaf Springs ◽  
Life Analysis ◽  
Fatigue Life Analysis

Purpose – The purpose of this paper is to investigate the fatigue and failure of commercial vehicle serial stress-peened leaf springs, emphasizing the technological impact of the material, the thermal treatment and the stress-peening process on the microstructure, the mechanical properties and the fatigue life. Theoretical fatigue analysis determines the influence of each individual technological parameter. Design engineers can assess the effectiveness of each manufacturing process step qualitatively and quantitatively, and derive conclusions regarding its improvement in terms of mechanical properties and fatigue life. Design/methodology/approach – Two different batches of 51CrV4 were examined to account for potential batch influences. Both specimen batches were subjected to the same heat treatment and stress-peening process. Investigations of their microstructure, hardness and residual stress state on the surface’ areas show the effect of the manufacturing process on the mechanical properties. Wöhler curves have been experimentally determined for the design of high-performance leaf springs. Theoretical fatigue analyses reveal the influence of every above mentioned technological factor on the fatigue life of the specimens. Therewith, the effectiveness and potential for further improvement of the manufacturing process steps are assessed. Findings – Microstructural analysis and hardness measurements quantify the decarburization and the degradation of the specimens’ surface properties. The stress-peening process causes significant compressive residual stresses which improve the fatigue life. On the other hand, it also leads to pronounced surface roughness, which reduces the fatigue life. The theoretical fatigue life analysis assesses the mutual effect of these two parameters. Both parameters cancel each other out in regards to the final effect on fatigue life. The sensitivity of the material and the potential for further improvement of both heat treatment and stress peening is appointed. Research limitations/implications – All quantitative values given here are strictly valid for the present leaf spring batches and should not be widely applied. The results of the present study indicate the sensitivity of high-strength spring steel used here to the various technological factors resulting from the heat treatment and the stress-peening process. In addition, it can be concluded that further research is necessary to improve the two processes (heat treatment process and the stress peening) under serial production conditions. Practical implications – The microstructure investigations in conjunction with the hardness measurements reveal the significant decrease of the mechanical properties of the highly stressed (failure-critical) tensile surface. Therewith, the potential for improvement of the heat treatment process, e.g. in more neutral and controlled atmosphere, can be derived. In addition, significant potential for improvement of the serially applied stress-peening process is revealed. Originality/value – The paper shows a systematic procedure to assess every individual manufacturing factor affecting the microstructure, the surface properties and finally, the fatigue life of leaf springs. An essential result is the quantification of the surface decarburization and its influence on the mechanical properties. The methodology proposed and applied within the theoretical fatigue life analysis to quantify the effect of technological factors on the fatigue life of leaf springs can be extended to any engineering component made of high-strength steel.

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