bluuebunny/crossref_metadata_2025 huggingface dataset:
The Microstructures and Properties of Carbon and Graphite Materials Prepared from Mesocarbon Microbeads by Different Molding Methods
Authors: Zhang Zu Qiong , Wan Hong , Cheng Xing Yu
Published: March 2016

Mesocarbon microbeads (MCMBs) are the prominent precursors for high-strength and high-density carbon and graphite materials (CGM). The microstructures and properties of CGM prepared by different compaction techniques using raw powders or pelleted powders of MCMBs with low content of β-resins was investigated in the present study. The green blocks by one-step uniaxial compaction at 230MPa were carbonized at 1200°C, forming carbon blocks with density of 1.84g/cm3 and bending strength of 76.9MPa. After graphitizing at 2700°C the carbon blocks are with density of 1.91g/cm3 and flexural strength of 70.5MPa. One-step cold isotropic pressing can improve the moldability of green blocks and increase open porosity of graphite blocks to 12.64vol%, with density of 1.87g/cm3. The green blocks with no cracks prepared by multistep cold isotropic pressing exhibit density of 1.84g/cm3 and bending strength of 81.7MPa. However, the flexural strength of these carbon and graphite artifacts decreased by 11.6~32.0MPa with comparison to the ones directly prepared from MCMBs.
Effects of Paste Composition and Sintering Process on Performance of Silver Paste for Silicon Solar Cells
Authors: Yan Fang Chun , Teng Yuan , Yan Ji Kang , Du Jing Hong , Yi Jian Hong , Yang Jian , Gan Guo You
Published: March 2016

In order to study the effects of composition ratio of silver paste and the sintering process on the properties of the silver film after sintering, the effects of different ratios of silver powders, glass powders and organic carrier in silver paste and different sintering temperatures and sintering time on the adhesion force and square resistance of the silver film were studied. The morphology of the sintered silver film was observed by SEM. The results showed that the silver film sintered at 760°C for 6 seconds had better properties after sintering when the ratio of silver powders, glass powders and organic carrier in silver paste was 80:5:15 and the silver powders was composed of spherical silver powders and flake silver powders at the ratio of 94:6. The adhesion force and square resistance of the silver film were 8.25 N and 3.47mΩ /□, respectively.
Effect of Ti Element on the Mechanical Properties of Cu-Matrix Bonding Diamond Tool Bits
Authors: Xiao Chang Jiang
Published: March 2016

Using the hot-pressing sintering method, Cu-matrix bonding diamond tool bits including 0, 4 and 8 % Ti content (wt.%) were prepared. The effect of Ti content on the mechanical properties of Cu-matrix bonding diamond tool bits was studied. The experimental results showed that the influence of Ti content on the flexural strengths of Cu-matrix bonding bits and diamond tool bits are significant. Furthermore, the morphologies and compositions of fracture surfaces of diamond tool bits were characterized by scanning electron microscope and energy dispersive spectroscopy. The results illustrated that when the Ti content was 4%, the interface bonding between the diamond and the Cu-matrix bonding was the strongest, the flexural strength had the maximum values of the Cu-matrix bonding bits and the diamond tool bits, the values were 644 MPa and 515.8 MPa respectively.
Microstructure and Mechanical Properties of the Weld Joint of Small Diameter Glass-Lined Metal Pipe with Inner Surface Layer
Authors: Liu Dong Ming , Han Bin , Li Li Ying
Published: March 2016

The width of 36mm of inner surface layer was formed by Ni625 welding wires in the ends of glass-lined 20# metal pipe, and the metal tubes were welded. The microstructure and the distribution of the main alloying elements of the weld joints were analyzed by optical microscope (OM) and electron probe microscope analysis (EPMA). The mechanical property and nondestructive inspection tests of the welded joints were carried out. The results show that the welded joints were divided into three layers including root layer, transition layer and cap layer. The microstructure in root layer was characterized by the cellular-dendrite structure. The transition layer contained martensite and retained austenite. The capping layer included acicular ferrite and pearlite. The defect free joint was produced and performed well. The concentration of nickel and chromium element in weld root were higher than inner surface layer which proves that welding wire of transition layer protects the major alloying elements in welding root.
Development and Application of Neutron Imaging Technique at China Advanced Research Reactor
Authors: He Lin Feng , Han Song Bai , Wei Guo Hai , Wu Mei Mei , Wang Yu , Li Yu Qing , Wang Hong Li , Liu Yun Tao , Chen Dong Feng
Published: March 2016

Neutron imaging (NI) has unique feature compared with X-ray imaging for the difference of the transmission characteristics through matters. The sensitivity to light elements, especially hydrogen, and the large penetration length through metals give it special advantages. NI has become a particularly useful universal technique for scientific and applied studies in various research disciplines. This article reviews the recent development of neutron imaging at China Advanced Research Reactor (CARR), including the instrumentations for indirect and real-time imaging and their application for non-destructive testing of nuclear fuel rod, two-phase flow, fuel cell, rock and concrete, etc.
Characterization of Local Crystal and Electronic Structure on Sr2CuO2F2+x Material by Synchrotron Radiation
Authors: Wang Hai Bo , Wang Qian , Ji Yan Dong , Yang Meng Meng , Dong Yong Qi
Published: March 2016

In order to study the evolution of local crystal and electronic structure of Sr2CuO2F2+x, the synchrotron radiation x-ray absorption (XAS) and x-ray absorption fine structure (XAFS) techniques were both performed on different amount of Sr2CuO2F2+x materials. The relationship between high Tc superconductivity and valence state of cooper was mainly discussed. And the effect of by-reproduce SrF2 in non-superconductive Sr2CuO2F2+x on physical property of this material was considered. The experimental results showed that the valence state of Cu and the amount of SrF2 was mainly related with high Tc superconductivity of Sr2CuO2F2+x material, indicating a good method for improving Tc.
In Situ Synchrotron X-Ray Diffraction Study of a Deformed Cu-Fe-P Alloy during Heating
Authors: Wang Wei , Zou Cun Lei , Li Ren Geng , Wen Wen , Kang Hui Jun , Wang Tong Min
Published: March 2016

In situ synchrotron X-ray diffraction was used to study a deformed Cu-0.88 Fe-0.24 P alloy during heating process. The measurements were performed at room temperature and also at high temperatures up to 893 K in order to determine the recovery, ageing and recrystallization process. With the increase of temperature, the angles of copper matrix peaks moved left and the FWHM (full width at half maximum) decreased slightly. Fe3P precipitates were first detected at 533 K, reached the maximum at 673 K, and re-dissolved into matrix at 853 K. A dramatic decrease in FWHM was observed accompanied by the precipitation of Fe3P phases, indicating the reduction of lattice distortion of copper matrix.
Alumina Growth and Interface Strengthening Mechanisms of Pt on the Surface of Bond Coats in EB-PVD TBC System Based on First-Principles
Authors: Wang Yi Qun , Song Peng , Liao Hong Xing , Ji Qiang , Lu Jian Sheng
Published: March 2016

Oxygen adsorption, aluminium segregation and interface adhesion on the surface of NiPtAl and MCrAlY bond coats (BC) in EB-PVD TBC system were investigated using first-principles calculations within the density functional theory (DFT). Examination of oxygen adsorption and aluminium segregation indicated that the addition of Pt always obstructed the growth of alumina. In addition, NiPtAl, as bond coats in EB-PVD TBC System, had less lattice variation and stronger interface adhesion than MCrAlY when alumina was produced. It is found that Pt is an important factor that affects the Al2O3 growth in thermal barrier coating. It is proved that Pt improves the bonding performance of Al2O3 and lifetime of thermal barrier coating. This offsets the high cost of Pt in industry application.
Finite Element Analysis on the Effect of the Texture to the Crack Tip Plasticity in Aluminum Alloy
Authors: Liu Ran , Huang Hui , Liu Jia Ju , Wang Wei , Rong Li , Nie Zuo Ren
Published: March 2016

Plasticity zone at crack tip of aluminum alloy with fcc structure is investigated in order to analyze the effect of crystal orientation to the plasticity distribution on crack tip, as well as the effect to CTOD and J-integral, which is implemented using finite element code in Abaqus with a rate dependent crystal plasticity theory. The results show that the crack tip plasticity, stresses and CTOD are significantly affected by grain orientations. When the grains have single textures, Cube and S orientations have a strong ability to against crack propagation. However, when the grains combine textures, the increasing of misorientation enhances the resistance for crack growth. And when the tilt angle is higher, the crack deflection is promoted to reduce the crack propagation rate.
Compression Deformation Flow Stress Behavior and Prediction of Pure Copper
Authors: Huang Shu Hai , Chai Shu Xin , Xia Xiang Sheng , Shu Da Yu
Published: March 2016

The deformation characteristics of pure copper have been investigated by compression tests in the temperature range of 20 °C~900 °C and strain rate range of 0.001 s-1~1 s-1. The results showed that the flow stress of pure copper increased with increasing strain rate and decreasing deformation temperature. Three types of strain-contained flow stress prediction models were developed. The flow stress prediction models based on parameters such as α, Q, lnA and n were related to deformation temperature, strain rate and strain, the prediction accuracy of the flow stress was deeply influenced by the cumulative error of multi-parameter fitting. The flow stress prediction model based on σ, , ε and T constitutive relations and the flow stress prediction model based on GA+BP possessed less correlation with microscopic deformation mechanism, proving to have high prediction accuracy, in which GA+ BP-based flow stress prediction model is in very good agreement with true stress curve, which is of significance to the guidance of hot working of pure copper.
Phase Stability and Elastic Properties of оne Dimensional Long Period Structures of Al3Ti under High Pressure
Authors: Tang Ping Ying , Huang Guo Hua , Xie Qing Lian , Huang Jin Li
Published: March 2016

Phase stability and elastic properties of seven one dimensional long period structures (1D-LPSs) of Al3Ti under high pressure have been systematically investigated by first-principles calculations. The enthalpy differences indicate that Al3Ti will undergo a phase transition from 1D-LPSs to L12 structure at high pressure. With increase of antiphase boundary period parameter M’, the enthalpy initially decreases and then increases, and the enthalpy for D023 is the smallest. Oppositely, the phase transition pressure firstly increases and then decreases, and the maximum is for D023. The elastic constants and elastic moduli B, G and E increase monotonically with increase of pressure, and the corresponding second-order polynomial fits are also obtained. Interestingly, the pressure dependence of Poisson’s ratio show similar tendency with that of B/G ratio. Both the B/G ratios and the Cauchy pressures reveal that these 1D-LPSs exhibit brittleness at high pressure.
Thermodynamic Database of the Phase Diagrams in the Sc-X Binary Systems
Authors: Li Jia Lian , Wang Shu Liang , Qin Xue , Li Yu Heng , Zhou Lu Jiang , Lin Yuan Hua , Liu Xing Jun
Published: March 2016

Sc-based alloys have been used as aero-structures materials, and Sc addition on wrought alloys has positive effects on weldability and welding properties. Phase diagrams play an effective role during the development of new type of alloy with good properties. Therefore, to establish the thermodynamic database of Sc-X binary systems is important and necessary.In the present work, the thermodynamic assessments of Sc-X (Ag, B, Cr, Er, Gd, Mo, Th, W, Y, Zr) binary systems was carried out by using CALPHAD (Calculation of Phase Diagrams) method based on the experimental data including thermodynamic properties and phase equilibria. The Gibbs free energies of the solution phases were described by the sub-regular solution model with the Redlich-Kister equation, and those of the intermetallic compounds were described by the sub-lattice model. A set of self-consistent thermodynamic parameters were derived for describing the Gibbs free energies of each solution phase and intermetallic compound. The calculated phase diagrams and thermodynamic properties are in good agreement with experimental data. The thermodynamic database of the Sc-X (Al, Ag, B, Ca, Co, Cr, Cu, Er, Fe, Ga, Gd, Ge, La, Li, Mg, Mn, Mo, Ni, Pb, Pd, Ru, Sn, Th, W, Y, Zn, Zr) binary systems have been developed, which can provide much important thermodynamic information for multicomponent Al-Sc based alloys.
A Method to Evaluate the Temper Embrittlement from Step Cooling Test
Authors: Wang Han Kui , Xu Tong , Shou Bin An
Published: March 2016

A new mathematic approach was proposed to evaluate the temper embrittlement from the step cooling test. The approach was composed of two parts. A nonlinear model, which acted as weight factor, was used to fit the variance at different test temperatures, and the maximum likelihood method was used to determine the curve parameters. In the ASME specification SA-542, there was no instruction to be provided on how to determine the transition temperature from the test results. This method is adopted as an additional supplementary requirement to assess the temper embrittlement of Chromium-Molybdenum steel.
Mechanical Properties and Fracture Behavior of Indirect Squeeze-Cast A354 Alloy Using Local Pressurization
Authors: Liu Hai Jun , Li Lie Jun , Niu Jian Wei , Gao Ji Xiang , Chen Xue Wen
Published: March 2016

The effect of local pressurization on mechanical properties and fracture behavior of indirect squeeze-cast A354 alloy has been investigated. As compared to conventional process, the porosity and shrinkage cavity for heavy sectioned squeeze castings were improved by the indirect squeeze casting, while its tensile properties were inferior to other parts of the casting. That is mainly due to that inhomogeneous eutectic Si particles within strip, angular and fragment shapes distribute in bulky α-Al cells, which is caused by slower solidification rate. After T6 treatment, the fragmentation and spheroidization of the eutectic silicon happened. Under this situation, the effect of fragmentation on α-Al matrix reduced. Tensile properties of the casting (both local pressurization part and non-local pressurization part) were enhanced greatly, by 36.8% and 25.4%, respectively. Fracture analysis results show that the type of fracture morphology is changed from mixed mode of brittle cleavage and ductile to ductile mode after T6-treatment.
Effect of Two-Step Aging on the Microstructure and Mechanical Properties of Cu-2.7Be Alloys
Authors: Zhu Dai Bo , Liu Chu Ming , Han Tan , Gao Yong Hao , Jiang Shu Nong
Published: March 2016

The effects of two-step aging on the microstructure and mechanical properties of Cu-2.7Be alloys were investigated in the present study, compared with one-step aging. After cold rolling the Cu-2.7Be alloys were heated by different combinations of temperature and time. The results revealed that two-step aging could obviously increase the strength of Cu-Be sheets when the aging temperature was 380 °C. At the temperature of 320 °C and 340 °C, there was no distinctly difference of strength and elongation between two-step aging and one-step aging. The SEM of fracture surfaces showed that the number of dimples increased with the increase of aging temperature.
Inhomogeneous Distributions of Sub-Grains and Precipitates in Strip-Cast 3wt% Si Steel Sheet
Authors: Wang Yang , Xu Yun Bo , Zhang Yuan Xiang , Fang Feng , Lu Xiang , Wang Guo Dong
Published: March 2016

A Fe-3wt% Si strip was produced using a vertical type twin-roll casting process. Sub-grains with an inhomogeneous distribution through the thickness direction were firstly observed in the as-cast strip. It was found that the surface layer was characterized by columnar grains containing lineage sub-grains, the subsurface layer was dominated by numerous polygonal sub-grains inside columnar grains or fine equiaxed grains, and the center layer was composed of coarse equiaxed grains without sub-grains. In addition, the sub-grain boundaries provided additional nucleation sites for precipitates and the nanoscale MnS particles were successfully obtained. Moreover, the average size of MnS precipitates in the surface layer was smaller than that in the subsurface layer. The inhomogeneous distributions of sub-grains and precipitates can be attributed to the large temperature gradient through the thickness direction during the strip casting process.
Effects of Cooling Rate on Morphology of Eutectic Si in RE Modified Al-10wt.%Si Alloy
Authors: Liu Wen Yi , Xu Cong , Xiao Wen Long , Liu Mao Wen , Zhang Jian Bin , Chen Jiu Xin , Ma Chao Li
Published: March 2016

Morphology evolution of eutectic Si in Ce-rich mischmetal (RE) modified Al-10wt.%Si alloy at different cooling rates was investigated. The morphology of eutectic Si and modification mechanism of RE was investigated by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The results showed that the RE modified eutectic Si exhibited a plate-like morphology under the low cooling rate (~100K/s). When cooling rate increased to ~600K/s, some branches were observed on the eutectic Si. In the RE modified alloy with a higher cooling rate (~1000K/s), the number of the branches on RE modified eutectic Si increased, and the morphology of eutectic S was modified to coral-like structure. The addition of Sr caused a flake-to-fiber modification of eutectic Si at low cooling rate, and the fiber size decreased with cooling rate increasing. The morphological observations indicated that the morphology of eutectic Si in RE modified alloy was significantly influenced by the cooling rate, while the modification efficiency of RE was lower than that of Sr.
Preparation and Characterization of Spray Formed 2060 High Speed Steel
Authors: Ni Xin Lei , Li Zhou , Yuan Hua , Xu Wen Yong , Zhang Guo Qing
Published: March 2016

Spray forming has attracted considerable attention for the production of high speed steels due to its potential and priority in the microstructure refining and cost saving. In this study, high-quality large billets of 2060 high speed steel were successfully produced by spray forming process using a twin-atomizer facility. As-deposited billet was subsequently processed by hot forging, quenching in oil at 1180 °C and a triple tempering in the temperature range of 500-580 °C. The microstructures and hardness of the deposit and their subsequent development resulting from hot forging and heat treatment were investigated. This paper was designed to provide insight and have a better understanding of such a system for the steel. The results showed that the as-deposited microstructure was composed of the fine equiaxed grains with V-rich MC and W-Mo-rich M2C carbides non-uniformly distributed along the grain boundaries and inside the grains. M2C presented rod-like or unconnected net-shaped morphologies in the as-deposited microstructure. Following hot forging, metastable M2C carbides were completely decomposed into refined MC and M6C nearly spherical carbides uniformly distributed throughout the microstructure. A hardness value of 31HRC was attained for the spray deposited and hot forged samples. With increasing the tempering temperature, hardness was increased firstly and then decreased. Secondary hardening peak appeared at 540 °C for spray formed 2060 steel austenitized at 1180 °C, and the corresponding peak hardness reached 71HRC.
Effect of Different Cooling Rates on Microstructure and Property of Continuous Annealing IF Steel
Authors: Zheng Ru Wen , Song Ren Bo , Fan Wu Yan , Wang Wei , Guo Ke , Wang Zhong Hong
Published: March 2016

The influence of different annealing cooling rates on microstructure,precipitation of the second phase and mechanical properties of IF steel was studied. The recrystallizing behavior of IF steels was analyzed by batch annealing process. After confirming the recrystallizing temperature of IF steel, the simulations of different continuous annealing cooling rates (5°C/s, 20°C/s, 50°C/s, 200°C/s 500°C/s and 1000°C/s ) were performed. At the same time, combined with TEM and XRD, the precipitating behavior and microstructure texture were analyzed. The results showed that the recrystallization temperature was speculated between 540°C and 560°C. As the cooling rate increased, the grain sizes became smaller and the yield strength increased significantly. And the tensile strength and elongation were more or less static. The tensile strength remained 240MPa and the elongation kept around 50%. With 1000°C/s cooling rate, the sample performed best with the r-value of 3.03. TiN precipitation was observed. The annealed texture is mostly composed of {111} texture.
Effects of Workpiece Size on Temperature Distribution During FSW of AZ31 Magnesium Alloy
Authors: Lu Sheng , Zhu Xing Yin , Liu Bin , Wang Yun Peng
Published: March 2016

This study aims to experimentally explore the effects of varying workpiece sizes on thermal histories and temperature distributions during FSW processes of AZ31 magnesium alloy. Similar layouts of thermocouples were designed to measure thermal histories of feature points at different locations along the welding direction. A tendency of peak temperature presented that it kept climbing gradually for a distance about 60mm, then approached to change smoothly. A time hysteresis has been also found that the time of the measured temperature reaching the peak lagged behind the time of the tool staying or arriving at these feature points. The longest hysteretic time was about 6s, as the welding process proceeded, it shortened slowly. The longer the length of the welding direction was, the more obvious the tendency was, but the hysteresis, on the contrary. The intense impact of the heat accumulation was embodied in terms of the time staying above the recrystallization temperature. According to these results, it is inferred that the welding process reaches a real stable stage after the tool traversed a 60mm’s distance.
Preparation of Alumina Powders through Pyrocatechol, Resorcinol Mediated Sol-Gel Method
Authors: Zhang Xiang , Li Ping Yun , Guo Xiao De , Yan Ting
Published: March 2016

Ultrafine alumina powders were synthesized through pyrocatechol and resorcinol mediated sol-gel process. Aluminum nitrate was applied as the Al source and PVP was the dispersant. X-ray diffraction (XRD) study displayed that γ-Al2O3 powders formed in the range of 800-900 °C, and then γ-Al2O3 transformed to α-Al2O3 at higher temperatures, pure α-Al2O3 powders could be obtained at 1000 °C by using resorcinol as organic monomer. The results of transmission electron microscopy (TEM) revealed that Al2O3 nanoparticles with γ crystalline phase had grain sizes in the range of 5-40 nm. Scanning electron microscopy (SEM) observation displayed that the morphology of the prepared α-Al2O3 powders had aggregated bodies formed by Al2O3 grains in the range of 0.2-0.5μm. These results provide a new way of preparation of alumina powders.
Effect of Enhanced Cooling on the Microstructure and Mechanical Properties of Friction Stir Spot-Welded AZ31 Magnesium Alloy
Authors: Chen Song Lin , Zhang Da Tong
Published: March 2016

AZ31 magnesium alloy was friction stir spot welded in air and cooling in water. The effect of the enhanced cooling rate on the microstructure and mechanical properties of the joint was analyzed. The results showed that flowing water had obvious cooling effect instantaneously, which significantly restrained the growth of dynamic recrystallized grains. The average grain size in stir zone was 1.3μm in cooling water condition, which is far smaller than that of the joint prepared in air cooling condition. Under the condition of enhanced cooling, the microhardness in stir zone significantly increased, the ultimate tensile load (~ 3.99kN) increased by 15.7%, and the tensile deformation value (~ 3.65 mm) increased by 62.2%. Dimples in SEM fracture morphologies indicated the better plastic deformation capacity of joints prepared by cooling water, which failed through a mixture mode of ductile and brittle fracture.
Mechanical Properties and Microstructures of 5052 Al Alloy Processed by Asymmetric Cryorolling
Authors: Shi Jin Tao , Hou Long Gang , Ma Cun Qiang , Zuo Jin Rong , Cui Hua , Zhuang Lin Zhong , Zhang Ji Shan
Published: March 2016

Aluminum alloy sheets were asymmetrically rolled at room and cryogenic temperatures by imposing different velocity ratios of 1~1.5 between the upper and bottom rolls. After rolling, the stress-strain curves, microhardness as well as the microstructures of the rolled samples were characterized and analyzed. The experimental results showed that the asymmetric cryorolling could improve the grain refinement and offered (~12%) higher room temperature tensile strength than that processed by symmetrical rolling with velocity ration of 1.0 (~280 MPa). However, at cryogenic temperature, the strength of asymmetrically cryorolling sheet (with velocity ratio of 1.5) was 5.1%, which is less than that processed by symmetrical rolling.
Creep Model of Natural Fiber Reinforced Polymer Composite
Authors: Xu Hai Long , Cao Yan , Wang Wei Hong , Wang Qing Wen
Published: March 2016

The flexural performance, 24 h creep-24 h recovery of the Populus alba wood fiber reinforced high-density polyethylene composites prepared by forming mat-compression molding method is investigated. Two-parameter power law model, Findley’s power law model and Burgers model are used to describe the 24 h creep curve of wood fiber reinforced polymer composite. Through model testing and parameter testing, and comparing the sum squared error of three models found that four elements Burgers model is successfully simulated with the creep resistance performances of resulted wood fiber reinforced polymer composites, and the two-parameter power law model is the worst. In summary, the four elements Burgers model is suitable for describing the creep performances of wood fiber reinforced polymer composites and predicting the safety and stability during application.
Process, Microstructure and Mechanical Properties of X90 Pipeline Steel
Authors: Guo Bin , Xu Jin Qiao , Cui Lei , Wang Qing Feng
Published: March 2016

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).
Simulated HAZ Continuous Cooling Transformation of X90 Pipeline Steel
Authors: Liu Yu , Ma Ai Qing , Feng Bin
Published: March 2016

In this paper, the simulation heat affected zone (HAZ) continuous cooling transformation (SHCCT) curve of X90 pipeline steel was drew by using Gleeble 3500 simulator. The results show that the trend of hardening of the weld HAZ of X90 pipeline steel was moderate, and softening tendency was not significant. When cooling rate was between 1°C/s and 10°C/s, the microstructure of X90 pipeline steel weld HAZ were composed of granular bainite and lath bainite. The recommended welding heat input of X90 pipeline steel was between 21kJ/cm and 66.4kJ/cm, and the weld preheating temperature was controlled about 100°C. In conclusion, optimization control measures on the microstructure and properties of X90 pipeline steel weld HAZ are presented by above comprehensive analysis.
Flexural and Creep Performances of Wood Fiber Reinforced Polymer Composite
Authors: Cao Yan , Wang Wei Hong , Xu Hai Long , Wang Qing Wen
Published: March 2016

In order to optimize the size of wood fiber reinforced polymer, and extend the application field of wood fiber reinforced polymer composites and improve the safety of their use, four size of wood fiber reinforced high-density polyethylene (HDPE) composites were prepared by forming mat-compression molding. The four kinds of fibers of different size include 80-120 mesh, 40-80 mesh, 20-40 mesh and 10-20 mesh fibers. The flexural performance, impact resistance performance and 24 hours creep - 24 hours recovery of the composites are studied. Fiber of 20-40 mesh presents the best flexural and impact resistance performance. The flexural strength, the elastic modulus and the impact strength reach 26.71MPa, 2.73Gpa and 6.88 KJ/m2 respectively. The impact performance of wood fiber/HDPE composites do not change a lot, while the fiber size increases from 10 to 80 mesh. However, the composites containing 80-120 mesh fibers has minimum impact performance. The creep performance of the wood fiber/HDPE composites with 80-120 mesh is the worst. After 24h creep test, the strain of the other three groups is almost the same. Creep recovery of the composites reinforced with 40-80 mesh fiber is the worst (61.74%). The creep recovery of the other three is above seven percent. Therefore, excessively large or small fiber size proves to be negative to improve the mechanical and creep performance, and polymer composites reinforced by them are not suitable for work under long-term load.
Continuous Cooling Phase Transformation Rules of High Nb X80 Pipeline Steel
Authors: Xia Pei Pei , Yang Liu Qing , Guo Xiao Jiang , Li Ye Zheng
Published: March 2016

The microstructural evolution of the high Nb X80 pipeline steel in Continuous Cooling Transformation (CCT) by Gleeble-3500HS thermal mechanical simulation testing system was studied, the corresponding CCT curves were drawn and the influence of some parameters such as deformation and cooling rate on microstructure of high Nb X80 pipeline steel was analyzed. The results show that as cooling rate increased, the phase transformation temperature of high Nb X80 steel decreased, with the microstructure transformation from ferrite-pearlite to acicular ferrite and bainite-ferrite. When cooling rate was between 20°C/s and 30°C/s, the microstructure was comparatively ideal acicular ferrite, thermal deformation accelerates phase transformation notably and made the dynamic CCT curves move upward and the initial temperature of phase transformation increase obviously. Meanwhile the thermal deformation refined acicular ferrite and extended the range of cooling rate accessible to acicular ferrite.
Identification of Kinematic Excitation Function by the Modal Coordinates Estimation of the System's Dynamics
Authors: Kaliński Krzysztof J. , Mazur Michał
Published: March 2016

The paper presents a method of the kinematic excitation courses’ identification in excitation points, based on the car road test acceleration at different measurement points. For the purpose of the laboratory fatigue life investigation of contemporary complex structures (e.g. cars bodies) and components of these structures (i.e. cars roofs), only a few first vibration modes are usually taken into account. During real life tests (i.e. road tests), accelerations at the selected points and along the defined directions are recorded and preprocessed appropriately. Subsequently, appropriate information about the measured acceleration allows us to identify such kinematic excitation function on the laboratory stand, whose result is the same as during the real road test. Thanks to the proposed approach, further time-consuming fatigue experiments can be performed on the laboratory stand.
Extended Kalman Filter in 2S1 Tracked Vehicle System with Hybrid Control
Authors: Jurkiewicz Andrzej , Kowal Janusz , Zając Kamil
Published: March 2016

The essence of the undertaken topic is the problem of estimation of state vector in the model of 2S1 tracked vehicle suspension system through the use of Extended Kalman Filter. The use of non-linear filter has become necessary due to the magnetorheological damper located at suspension system, which has been described by hyperbolic model. Application of the damper caused the tested suspension system has become a semi-active structure in which the hybrid control was applied. The choice of this type of control stems from the fact that in the case of tracked combat vehicles in addition to the advantageous conditions of work of vehicle crew also cornering stability and the possibility of sudden acceleration or braking is important. The hybrid control allows to determine a compromise between ride comfort and stability of 2S1 platform.
Effectiveness of the Sliding Mode Control in a Two Coupled Discontinuous Dynamical Systems with Dry Friction
Authors: Olejnik Paweł , Awrejcewicz Jan
Published: March 2016

Numerical modeling and a tracking control of angular velocity of a rotor measured in the assumed sliding contact bearing subject to a discontinuous dynamical loading has been performed in this contribution. A contact interface in the direct current motor’s sleeve bearing has been treated as a dynamical system with dry friction, including a few sources of the stick-slip and creep-slip effects. The object of control is subject to an irregularly changing torque generated by another discontinuous dynamical system with friction. The loading comes from a block-on-belt model of a conveyer system with intensification of friction force, which has been elastically coupled with the direct current rotor’s shaft by means of the transmission belt. Therefore, the dynamic loading of the DC motor changes because of time-varying linear velocity of two belts. If such additional torque oscillates while the rotational velocity of the motor’s shaft is small due to a requirement, then it significantly affects the entire system’s dynamics producing stronger nonlinear response of the motor’s speed.
A Technical & Economic Study of Offshore GTL Comparing with Gas Export and Gas Re-injection
Authors: Kim Wonseok , Choi Dong-kyu , Moon Youngsik , Jang Na-Hyung , Lim Hye-Won , Kwon Hyuk , Denholm Douglas , Park Taeshin
Published: March 2016

Objective/Scope: Associated gas occurring in the offshore production facilities has traditionally been handled by flaring (primarily), gas export, and gas re-injection. Operators and owners have preferred to flare in many cases because gas export and re-injection are either very expensive or infeasible. Global interest in eco-friendly solutions has recently increased in the area of offshore oil & gas fields.

To achieve zero-flaring for oil & gas production site, "Modular Gas-to-Liquids (GTL)" and "GTL Floating Production Storage and Offloading (FPSO)" has been researched as candidate zero-flare methods. Our goal is to develop a portfolio of zero-flare solutions to support business development by making technical & economic comparisons of gas export, gas re-injection and offshore GTL.

Methods, Procedures, Process: In the view of EPC contractor, the technical & economic feasibility study for Offshore GTL application was studied and analyzed. Several gas handling methods (e.g. gas export, gas re-injection, and Offshore GTL) were compared and analyzed to figure out which technology is the best option for associated gas handling for offshore oil & gas fields. We also studied which method would be more competitive depending on gas production capacity, distance from onshore to offshore, crude oil price, and natural gas price in offshore oil & gas fields. Moreover, economic analysis was performed to identify the major cost factors & ranges and to understand their impact on the project.

Results, Observations, Conclusions: The feasibility study of GTL module on FPSO has been lately completed to acquire the preliminary technical & economic comparison of gas export, gas re-injection and Offshore GTL for developing oil & gas fields in offshore. The results of this study suggest that concepts of GTL application can be technically and economically more competitive than gas export and gas re-injection in some offshore oil & gas fields. The GTL products are more profitable than export & re-injection gas in the energy markets within the range of the current project cost factors.

Novel/Additive Information: It must be a great opportunity to set up a cooperation network for the next stage of developing Offshore GTL. The cooperation network will research and develop Pre-FEED for Offshore GTL and the result will bring commercial realization of this innovative approach of oil & gas fields in offshore.
The Importance of SIMS in Structural Integrity Review and Life Extension Requirement for Existing Fixed Offshore Structure
Authors: Kajuputra Alex E. , Shiiun Wong Bak , Shamsuddin M. Akmal
Published: March 2016

The demand to perform structural integrity review and life extension for existing fixed offshore structures is increasing in order to support the changes arising from new technologies for production enhancement, in-service deteriorating conditions and regulatory requirements on ageing structures. An understanding of fitness-for-purpose criteria is required in performing assessments on existing structures. The criteria as described in performance standards will define the status of structures as one of the Safety Critical Elements (SCE) in offshore fixed platforms.

This paper presents an effective and rational approach in assessing the structural integrity and life extension requirements of ageing offshore structures. The pre-defined performance standards are set from the perspective of SIM (Structural Integrity Management) implementation, which are defined in terms of F.A.R.S.I according to UKOOA: Guidelines for the Management of Safety Critical Elements Standard. It stands for Functionality; Availability; Reliability; Survivability; Interactions.

The acceptance criteria is set to meet the SCE goal for operational and accidental or abnormal events. The structure shall be able to support the platform facilities under all identified loading conditions within the allowable stress set for load bearing members. The overall structures shall have a minimum integrity without collapse for the specified minimum survival time related to facility emergency response for design accident events. The structure shall also be able to accommodate the future changes in facility and estimated degradation for life extension requirement.

The SIM as referred to API RP 2SIM is the basis for developing the assessment criteria, which is defined in terms of F.A.R.S.I. It covers the four phases required in SIM, which are Data, Evaluation, Strategy and Program. The quality of SIM implementation by the asset owner on the offshore structures will determine the assessment results and are accordingly verified against the pre-defined acceptance criteria. This process will determine the gaps in SIM implementation and provide recommendations on corrective actions for gap closure.

The requirements of management of change (MOC) in relation to SCEs, role and responsibilities, execution plan, result management and documentation are also covered here. These are normally covered in structural integrity manuals that outline the processes for the conduct of structural integrity programs.
Development of Sand Erosion and Transport Software for Efficient Sand Management
Authors: Baghdadi F. , Gupta A. , Kamat D. , Singh R. , Borhan A. B. , Jadid M. B.
Published: March 2016

Assessment of Sand Transport and Erosion is a crucial part of sand management. Though there are various correlations in the industry to model this, it still comes down to analysis and systematic usage of the correlations and related calculations in order to deliver a successful Sand Management plan. As part of the initiative to implement the Holistic Sand Management Approach in PETRONAS, it is crucial to establish sand erosion and deposition models. For this a user friendly software need to be developed. This software is able to model the sand erosion and deposition in the critical elements of the production system. The flexibility of programming enhanced the utility by including publicly published as well as in-house correlations establishing an efficient sand management process.

The software can run calculations as a standalone (offline) or linked to a three phase simulator software or any integrated operation platform to assess erosion and sand deposition risk online. The use of an interactive dashboard eases the complexity of user by keeping all the correlations in background while able to run sensitivities to plan a better sand risk management.

The sand transport and erosion management software not only calculates erosion rates and critical velocities for sand depositions for all lenses in production system; tubing, pipelines, bends, chokes and headers, etc. but can also be linked to a production database to calculate the cumulative metal loss and predict the remaining pipe thickness or any pipe element life.

This software helps in decision-making using (1) novel concept to obtain optimum gas-lift injection rate based on erosion risk and flowing pressure (2) generating a safe sand erosion envelop (3) back calculation of critical rate for sand deposition instead of critical velocity. Moreover the software raises flags or alarms wherever erosion or deposition risk occurs in the system. It can also run sensitivities for all the parameters that affect deposition or erosion.

The paper details the procedure involved to further validate and calibrate the in-house erosion and deposition models for effective and accurate calculations.

The software helps in the whole approach of sand management by giving insight into the erosion and sand deposition risk in production system enabling safe operation condition. This can be beneficial for design considerations during FDP formulation stage for a sand-prone field or even at later stage of production when the safe operating limit for sand production can be increased resulting in higher production. All this provides significant economic gain by replacing the hardware part (sensors) or in case of sensors available in place it will help in testing the accuracy of the correlations as well as to calibrate them to fit into real conditions.
The Role of Computational Fluid Dynamics and Wind Tunnel Testing in Validating Floating LNG Project Technology Design
Authors: Green Johnathan , Sivandran Subajan
Published: March 2016

The objective of this paper is to discuss and demonstrate how numerical modelling, such as Computational Fluid Dynamics (CFD), can be used with detailed physical testing, such as Wind Tunnel Testing, to validate the design of Floating Liquefied Natural Gas (FLNG) units and Floating Production Systems (FPS). The paper will discuss the importance of numerical modelling and / or wind tunnel testing during the design phase. It will be highlighted that numerical modelling does not replace pure theoretical or pure experimental results but acts as a complement in gaining a greater overall picture. Using case studies, findings will be presented in such a way to discuss the advantages of both approaches and highlight findings where one technique may be more suitable than the other. Numerical modelling can be used to analyse a number of different issues such as the risks associated with the loss of containment of hydrocarbons and their subsequent ignition or the impact of turbine exhaust dispersion and turbulence on helicopter operations. Wind Tunnel Testing, on the other hand, can be used to determine wind and current loads acting on the FLNG topsides and hull and can avoid conservatism in design reducing size and weight (e.g. mooring loads) and therefore reduce costs.

Using both wind tunnel testing and numerical modelling will highlight key design recommendations that can be made early in the design process, considerably optimising design and ensuring the FLNG unit or FPS can last throughout its operational design life.
New On-Command Integrated Expandable Under Reamer Technology Reduces Operational Uncertainties and Saves Operational Cost
Authors: Fang Lei , Schwartze Sascha , Grindhaug Gaute , Kanzler Christian
Published: March 2016

A new integrated expandable reamer technology was jointly developed by a major Norwegian operator and a service company, and was field tested at offshore Norway and the Gulf of Mexico deepwater environment. The reamer is fully integrated with the company's rotary steerable systems, enabling flexible and optimal placement of reamers in the bottom hole assembly (BHA), unlimited on-demand activation cycles, and real-time feedback via mud pulse telemetry. The flexibility of placement in the BHA allows the reamer to be used as a near bit reamer, a main reamer, or a combination of both. When used for near bit reaming service, the reamer can reduce the rat hole length to a minimum of 4 meters, compared to a standard 50 to 70 meters, in the same run. Substantial time savings can be achieved by removing the need for a dedicated rat hole elimination run. The unlimited activation/deactivation cycles are achieved through mud-pulse telemetry, and each cycle takes less than five minutes. The real-time feedback from the reamer includes confirmation of blade activation status as fully extended, reducing operational uncertainty during reaming and saving time for a shoulder test that is otherwise required.

Since being introduced offshore Norway, the technology has been successfully applied as both main and near bit reamers. It has proven its capability as a reliable main reamer as well as an integrated near bit reamer reducing rat hole to a minimum while maintaining full directional drilling control and enabling full Measurement While Drilling (MWD) and Logging While Drilling (LWD) measurements. Real-time feedback from the reamer reduced operational uncertainty and enabled efficient drilling.

This paper presents the main features and functionalities of the new expandable reamer technology and discusses results from two field testing runs at the Grane field in offshore Norway.