bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure Analysis and Solution to Bimetallic Lined Pipe
Authors: Li Fa Gen , Li Xun Ji , Li Wei Wei , Wang Fu Shan , Li Xian Ming
Published: May 2020

Owing to low cost, excellent pressure and corrosion resistance, bimetallic lined pipes were regarded as one of the most important methods to resolve corrosion of traditional steel pipes used for oilfield. Nowadays, the pipes are widely used in the projects of oil and gas gathering and transportation. However, there were some failure cases in succession in recent years. In this paper, the failure causes were excavated from multiple perspectives, and on this basis further countermeasures were put forward. Firstly, three typical failure accidents, including CRA layer collapse, CRA layer corrosion and weld joint failure, were listed throughout the whole life cycle from product ordering, construction technology to later operation. Secondly, failure analysis was carried out from five aspects: product quality, test technology, welding process, standard specification and application threshold, and a serial of comprehensive views were proposed. 1) Manufacturing period: Water seepage and tightness between CRA layer and backing pipe could not be effectively monitored. The ratio of collapse test was low so that proposed relevant risk could not be eliminated; 2) Welding period: the process has high risk failure in theory and lack of process assessment and construction acceptance standards. Potential danger could not be effectively assessed, and weld quality could not be guaranteed; 3) Application period: The CRA application range remained unclear, and bimetallic lined pipes were used in the environment beyond the threshold sometimes. The paper also summarized further improvement measures and research directions about these five aspects, including process quality, inspect technique, welding process, standard specification and application range. Finally, solution suggestions were proposed for the whole chain from manufacturers, testing institutions, construction units to oilfield users.
External Stress Corrosion Cracking Risk Factors of High Grade Pipeline Steel
Authors: Zhu Li Xia , Luo Jin Heng , Wu Gang , Li Li Feng , Li Lei , Wu Yi
Published: May 2020

The influence weights of various sensitive factors, such as steel grade, applied potential, temperature and soil environment, on stress corrosion cracking behavior of high-grade pipeline steel were studied by means of orthogonal test at mixed level and slow strain rate test. The stress corrosion behavior of X80 pipeline steel in near neutral and high pH simulated soil solution under overprotection potential was observed by SEM. The results showed that the applied potential has the greatest weight on stress corrosion index of ISSRT, followed by temperature, steel grade and soil environment. X80 pipeline steel exhibits high stress corrosion sensitivity in near-neutral and high pH simulated soil solutions at applied potential of -1500mV, and its SCC mechanism is hydrogen embrittlement (HE). This study can provide guidance for practical engineering application of pipeline steel.
Failure Cases Analysis in Aerospace Field
Authors: Lv Jia Hui , Wang Wei Ze , Tu Shan Tung , Liu Shao Wu
Published: May 2020

The major concern in the aviation industry is the flight safety. Although great effort has been put into the development of material and system reliability, the failure cases of fatal accidents still occur nowadays. Due to the complexity of the aviation system and the interaction among the failure components, it is difficult to do the failure analysis of the related equipment. This study focused on surveying the failure cases in aviation, which were extracted from failure analysis journals, including Engineering Failure Analysis and Case studies in Engineering Failure Analysis, in order to obtain the failure sensitive factors or failure sensitive parts. The analytical results showed that among the failure cases the fatigue failure is the largest in number of occurrence. The most failed components are the disk, blade, landing gear, bearing, and fastener. The frequently failed materials are steel, aluminum alloy, superalloy and titanium alloy. Therefore, in order to assure the safety in aviation, more attention should be paid to the fatigue failures.
One-Step Synthesis of Visible-Responsive Diatomite/g-C3N4 Composite and its Catalytic Degradation for Cr(VI)
Authors: Ren Yu Quan , Sun Shi Yong , Acheampong Edward Opong , Dong Fa Qin , Ma Biao Biao , Wang Ke , Fan Xiao Yu
Published: May 2020

A one-step synthesis of visible light responsive diatomite/g-C3N4 composite material was prepared by impregnation-calcination method. The products were characterized by Scanning electron microscope, X-ray diffractometer, Ultraviolet diffuse reflectance spectroscopy, Fourier transform infrared spectrometer, and Photoluminescence spectrometer. The SEM results showed that g-C3N4 was successfully attached onto the surface of the diatomite. Also the composite materials were more light-responsive compared with the single phase material. The composite materials had a maximum degradation efficiency up to nearly 91.79%. The significant improvement in photocatalytic performance was due to the porous structure of diatomite, increase of contact area of carbon nitride.
Effect of Cement Raw Meal on the NO Reduction by Biomass Char
Authors: Li Nan , Cui Su Ping , Wang Ya Li , Ma Xiao Yu , Liu Shi Jie , Zheng Yan
Published: May 2020

The influence of cement raw meal on the NO reduction by biomass char at a high temperature of 900 °C with four O2 concentrations of 1%, 3%, 5% and 8% was investigated in a laboratory scale fixed bed quartz reactor. The results showed that the cement raw meal had certain positive effect on NO reduction by biomass char which promotes dissociation adsorption of NO with the help of CO consumption and oxygen transferred to carbon surface, however, it also shows some negative effect, and the degree depends on O2 concentration. A long-time and high NO reduction rate was obtained in the case of 1% O2 concentration.
Preparation of Alginate Polymer Gel Pellets and its Adsorption on Acid Dyes
Authors: Li Bei Gang , Yin Hai Yang
Published: May 2020

A novel calcium alginate (SA/Ca) gel pellet adsorbent was prepared by ion exchange reaction and polymerization between sodium alginate (SA) and Ca2+ in the solution, and characterized by SEM, EDS, FTIR and XRD. Taking acid orange II ( AO II) dye as the adsorption object, the influence of some important conditions about preparation and adsorption on SA/Ca properties was discussed in detail. The adsorption kinetics were studied. The results show that SA/Ca adsorbent has good adsorption effect on AO II dye under the conditions of the mass concentration ratio 2 : 5 of SA and CaCl2 solutions and reaction time of 2h at 25°C. When the adsorbent dosage is 4g/L and initial dye concentration of natural pH is 1000 mg/L, the adsorption equilibrium can basically reach in 180 min at 25°C with the adsorption capacity of 225mg/g and more than 90% of removal efficiency. The adsorption kinetics fully fit pseudo-second order model. The characterization results indicate that the SA powder is composed of various irregular particles, while dry SA/Ca solid are all pellets with diameter of about 1mm. The surface of inhomogeneous spheres is stacked with obstacles, and folds and ravines coexist. Ca2+ and most Na+ in SA molecule carried out ion exchange and formed a stable network-structure polymer SA/Ca gel pellets, which can effectively remove acid dyes from wastewater, and are easy to be separated after adsorption. As a biopolymer adsorbent with simple preparation method, environmental friendliness and non-toxic side effects, SA/Ca has good development potential and application prospects.
Preparation of Hydrated Calcium Silicate Gel and its Adsorption Properties for Cu(II)
Authors: Liu Shi Jie , Cui Su Ping , Guo Hong Xia , Wang Ya Li , Li Nan , Gan Yan Ling , Zheng Yan
Published: May 2020

Calcium silicate hydrate gel (CSH) was synthesized by calcium acetate and sodium silicate. The structure and morphology of CSH were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy and Scanning electron microscopy. The adsorption performance of CSH was measured by static adsorption method. The results show that CSH has porous structure and large specific surface area, and the optimum reaction conditions is the reaction temperature of 25°C and calcium-silicon ratio of 1.2. It has the maximum adsorption capacity of more than 150 mg/g and the removal rate of more than 86% with Cu2+. And it shows the excellent adsorption performance, even when the concentration of Cu2+ is less than 200mg/L, the removal rate is above 90%. The research may provide a low-cost and high-efficiency adsorbent.
Life Cycle Assessment of Comprehensive Utilization of Calcium Carbide Slag in Cement Kiln
Authors: Lin Xin Ping , Liu Ai Wei , Feng Yun Fa , Chen Qi Ling , Chen Tao , Hao Li Wei , Li Xiao Qing
Published: May 2020

The recycling utilization of solid waste is an important technical means for the sustainable development of the cement industry in China. Calcium carbide slag is a special solid waste in China, which can be used for cement production with a great advantage on CO2 emission reduction. With an view to providing methodological and data support for the development of policies in the cement industry, this paper quantitatively analyzes the environmental effects/environmental benefits of the comprehensive utilization of calcium carbide slag in cement kiln by comparing the traditional system of Portland cement clinker completely produced by natural resources with the system of cement clinker produced by calcium carbide slag based on the life cycle assessment (LCA) method given in standards and specifications of ISO 14040 series. The results show that the latter system has a better effect in material saving and carbon emission reduction, will increase the energy consumption in cement production process, and also slightly increase other pollutants (e.g. SOx, NOx, etc.) emission. The GWP, AP and EP indicators of the calcium carbide slag cement clinker system decrease compared with those of the Portland cement clinker system, while other indicators do not differ much or even slightly increase.
Quantitative Analysis on Green Product Index of Sanitary Wares
Authors: Ren Shi Wei , Zhang Yan Jiao , Huang Meng Chi , Ma Li Ping
Published: May 2020

Rapid economic growth is often accompanied by ecological environment problems arising from resource and energy development, industrial production, etc. Consumers are increasingly concerned about environmental problems in consumer markets and prefer to buy "green" products. How consumers identify "green" products and how the country guides in choosing such products have become issues of great concern in the building materials industry. In this paper, the author has built the preliminary quantized model of green product index for sanitary wares by analyzing the green product index of sanitary wares and defining the green attributes of sanitary wares from such four aspects as consume attribute, resource attribute, energy attribute and environmental attribute.
Semi-Solid Rheological Squeeze Casting Process of ZL114A Aluminum Alloy Thin-Wall Complex Casting
Authors: Xu Yong Tao , Guan Tian Yang , Zhang Zhi Feng , Bai Yue Long , Mao Wei Min
Published: May 2020

High-strength aluminum alloy with large-scale and thin-walled complex castings have broad application prospects in aerospace, weapons, electronics, defense and military industries. However, due to the uneven thickness of the plate, the casting defects are inevitable by the ordinary casting method, and it is impossible to accurately control the shape and performance of the casting in the casting process. Previous studies have found that the semi-solid rheological extrusion casting technology with short process and near-end type can help solve this technical problem. Therefore, this paper studies the semi-solid rheological extrusion casting process of thin-walled complex casting of ZL114A aluminum alloy. The combination of numerical simulation and experimental research is used to simulate and optimize the filling and solidification process of thin-walled specimens. Based on this, a semi-solid rheological extrusion casting test was conducted. The result showed that, (1) The optimized model can well reflect the filling and solidification process under different rheological extrusion casting parameters, and obtain defect-free castings through process optimization. (2) The thin-walled parts of the thin plate casting produced by semi-solid rheology extrusion have excellent mechanical property and ductility.
Fatigue Crack Growth Behavior of TA29 Titanium Alloy at Different Temperatures
Authors: Li Juan , Cai Jian Ming , Duan Rui , Huang Xu
Published: May 2020

TA29 titanium alloy forging was heated by duplex annealing. The fatigue crack growth behaviour of the alloy at room temperature, 400 °C, 500 °C and 600 °C was studied. The relationship between the fatigue crack growth rate (Da/dN) and the stress intensity factor amplitude (△K) of TA29 alloy at different temperatures was revealed by Paris formula. The fatigue fracture morphology of fatigue crack growth specimens was analysed by scanning electron microscopy (SEM). The results showed that the TA29 titanium exhibited good crack growth resistance at room temperature. With the increase of test temperature, the C value of the Paris formula increased, the m value decreased, and the fatigue crack growth rate increased. From the fatigue fracture morphology of the specimens, it was found that the fractures of fatigue crack growth specimens at different temperatures exhibited typical pre-splitting zone, steady-state expansion zone and rapid expansion zone. As the temperature increased, the range of the pre-cracking zone was larger, the range of the steady-state extension zone and the rapid expansion zone were smaller. At room temperature, there was no obvious fatigue strips in the steady-state expansion zone, and the transient fracture zone exhibited the characteristics of cleavage fracture, while the steady-state expansion zone at high temperature showed obvious fatigue strips and secondary cracks, and the transient fracture zone was a typical ductile fracture mechanism.
Preparation of 2A14 Aluminium Alloy Large-Sized Hollow Ingots by Electromagnetic Stirring DC Casting
Authors: Li Xiao Peng , Li Bao , Gao Zhi Hua , Guan Tian Yang , Gao Ming Wei , Chen Chun Sheng
Published: May 2020

The Φ730 / Φ340 mm hollow ingots of 2A14 aluminium alloy were produced by conventional and electromagnetic stirring (EMS) DC casting with extremely fine grain morphology. The results indicate that the metallographic microstructure of the alloy was more uniform and homogeneous in the EMS hollow ingot and the finer grain size was obtained. The average grain size dramatically decreased from 115 μm to 70 μm with applying EMS. The macrosegregation patterns of Cu element in EMS and conventional hollow ingots along the radial direction were both following the similar trend that positive segregation occurred in inner subsurface and middle section. Meanwhile negative segregation occurred in section offset to inside of centerline and outer surface. The extent of macrosegregation in EMS hollow ingot was severer than that in the conventional one. The mechanism of EMS was discussed to reveal its effect on the microstructure and macrosegregation.
Oxidation Behavior of Ta-W Alloy
Authors: Li Jia Xin , Chen Yu Hong , Bai Zhang Jun , Du Shuai , Wu Lan Er
Published: May 2020

The oxidation behaviors of tantalum-tungsten alloy with 10-20% W was investigated between temperature range of 700 to 900 °C exposed in air. The kinetics of Ta-W alloy was determined by TG-DTA, the characteristics of oxides were analyzed by SEM, EDS and XRD. The oxidation tests revealed that the alloys obeyed parabolic kinetic in the initial stage, then translated in linear law. The addition of W has a good effect on the oxidation resistance of Ta-W alloys at experimental temperature. Solid solution of Ta2O5form in case of oxidation product of Ta-10W, Ta-15W alloys, while the complex oxide Ta22W4O67form after Ta-20W alloy oxidized. The formation of solid solution and complex oxide impeded the volatilization. The compact oxide film protects the penetration of oxygen in the initial oxidation stage. The large compressive stresses and mismatch of the coefficient of thermal expansion between oxide scale and matrix alloys make the oxides layer be broken, which cause kinetic of oxidization obeying linear law.
Removal Mechanism of Titanium Alloy Material in Ultrasound Vibration Drilling
Authors: Wang Tian Qi , Liu Zhan Feng , Qiu Yuan Ying , Feng Ya Zhou , Han Xiao Lan
Published: May 2020

In drilling the ultra-slim small diameter deep hole of titanium alloy, the problem of chip breaking and chip removal is common. When the drill is working normally, the ultrasonic vibration can be applied for the drill bit to cut the bit in the vibration to form a pulse. The cutting force waveform in drilling, should select the reasonable vibration frequency, amplitude, feed amount, workpiece rotation and other parameters to match, control the size and shape of the chip, get satisfactory chips, and avoid chip clogging. In this study, the ANSYS finite element simulation software was used to simulate the TC4 drilling process, and the difference between ultrasonic vibration drilling and ordinary drilling was analyzed. Drilling experiments were carried out. The experimental results show that compared with conventional drilling, ultrasonic vibration drilling has better surface quality, reduced tool wear and increased material removal rate.
Precipitation Behavior and Strengthening Mechanism of Second Phases in AZ31-1.3Ca-1.0Sm-0.3La Alloy
Authors: Fu Li , Hu Wen Xin , Le Qi Chi , Jia Zheng
Published: May 2020

A new type of AZ31-1.3Ca-1.0Sm-0.3La alloy was obtained in this study by adding Ca, Sm and La to AZ31 alloy. Detailed analysis results on second phases showed that Al2Ca phases, Al2Sm phases with two kinds of morphologies formed in as-cast AZ31-1.3Ca-1.0Sm-0.3La alloy besides Mg17Al12 phases, and La atoms mainly dissolved in Al2Ca/Sm phases. The average grain size of as-cast AZ31-1.3Ca-1.0Sm-0.3La alloys was 212 μm and the grain sizes distributions were uniform. After the hot extrusion, the average grain size decreased to 5.4 μm and the grain sizes distributions were uneven. The base texture of as-extruded AZ31-1.3Ca-1.0Sm-0.3La alloy was strong, and the maximum density value was 3.25. The yield strength, ultimate tensile strength and elongation of as-extruded AZ31-1.3Ca-1.0Sm-0.3La alloy was 216 MPa, 280 MPa and 16% at RT, and 145 MPa, 188 MPa and 42% at 150°C, respectively, which are much higher than those of the common MB2 alloy both at the room temperature and 150 °C.
A Review on Water Footprint Research of Materials Industry
Authors: Chen Hua Long , Liu Yu , Gong Xian Zheng , Hao Li Wei , Sun Bo Xue , Li Xiao Qing
Published: May 2020

The scarcity of water resource has become one of major issues that constrain economic development and urbanization process in China. The water footprint is a comprehensive indicator used to measure water consumption and pollution that is widely used in global or regional studies. The previous practices showed that water footprint analysis was an effective tool to achieve sustainable utilization of water resources by guiding the development of water-saving technology and product. This paper reviewed the progress of water footprint research in materials industry including related theory, method and application. Firstly, the basic concept of water footprint was introduced. Secondly, the current accounting and assessment methods of water footprint and their applicable fields were summarized. Thirdly, the case studies on the water footprint of metallic materials, nonmetallic materials and chemical materials were reviewed to analyze its guidance significance on the sustainable development of water resources. At last, some suggestions for future research on the water footprint of materials were proposed.
Progresses on Development of Manufacturing Methods of High Purity Tungsten Targets
Authors: Qi Yu , He Xin , Ding Zhao Chong
Published: May 2020

Tungsten has many excellent properties such as high melting point, high electrical conductivity, high electromigration resistance, high electron emission coefficient, high thermal stability and so on. Because of these excellent properties, high purity tungsten targets have wide applications and development prospects in the integrated circuit (IC) industry. In this paper, some manufacturing methods of tungsten targets was summarized and analyzed. The high melting point of tungsten makes powder metallurgy (PM) be the manufacturing methods of tungsten targets. After preforming of the tungsten powders, some sintering and densification processes like atmosphere pressure sintering, Hot Pressing (HP), Hot Isostatic Pressing(HIP) have been carried out. The grain size and the density of the tungsten targets is different by different manufacturing methods.
Growth Kinetics of Interfacial Intermetallic Compound in Al(AA4343)/Steel(SUS316) Clad Strip
Authors: Zhang Xiao Jun , Gao Kun Yuan , Hu Xiu Hua , Ding Yu Sheng , Wang Guo Zhan , Wu Xiao Lan , Nie Zuo Ren
Published: May 2020

The composition and microstructure of intermetallic compounds (IMC) at the interface of aluminum(AA4343)-stainless steel(SUS316) were studied upon annealing at 550°C for 1h to 20h and at 610°C for 15min to 10h by means of optical microscope(OM) , scanning electron microscope (SEM) with energy dispersive system(EDS) and transmission Electron Microscopy (TEM). The results showed that the IMC was of 4.3μm to 36.1μm thick during heat treatment at 550°C for 1h to 20h, and the IMC contained Al-Fe-Si-Cr-Ni-Mo and Al-Fe-Si -Ni. During annealing at 610°C for 15min to 5h, the thickness of IMC was 31.2 μm to 208 μm, and the IMC were mainly of η-Fe2Al5 and τ10- Al4Fe1.7Si at 550°C for 10h. As the annealing time extended to 10h, natural delamination occurred at the interface between the aluminum alloy layer and IMC layer. The growth kinetics analysis showed that the relationship between the thickness of IMC “X” and time “t” followed the relational equation X=(kt)n. For AA4343(solid) - SUS316(solid), n was 1/2, and the growth constant k = 1.9×10-13m2/s at annealing temperature of 550 °C. When the temperature was 610°C, AA4343 - SUS316 was a liquid-solid contact reaction, n was 1, the growth constant k=1.45×10-8m/s.
Effect of Thermal Aging on the Stress Corrosion Cracking Sensitivity of Z3CN20.09M Stainless Steel
Authors: Wu Huan Chun , Ti Wen Xin , Li Cheng Tao , Zhu Ze Jie , Cao Fa He , Fang Ke Wei , Zhang Guo Dong , Xue Fei
Published: May 2020

The stress corrosion cracking (SCC) sensitivity of aged Z3CN20.09M stainless steel (SS) was investigated by scanning electrochemical microscopy (SECM), nanoindenter and slow strain rate tensiometer (SSRT). The results indicated that the hardness and modulus of the samples increased with increasing aging time at 475 °C, which increased about 80% and 15% respectively after aging for 1000h. After immersed in NaCl+HCl solution (pH=2) for 7 h, the pitting corrosion point appeared of specimen aged for 1000h. While it was not found even for 24 h of as-received (AR) and aged for 500 h specimens at the same condition. The SCC sensitivity was increased about one time of the specimen aged for 1000 h tested in 300 °C high temperature water. The combined effect associated the embrittlement of mechanical properties and the decrease of corrosion resistance is regarded as the main reason for the increasing of SCC sensitivity.
Effects of Zero Time Holding Quenching Temperature on Tempering Microstructure and Mechanical Properties of 40Cr Steel
Authors: Zhu Peng Xiao , Li Yi , Chen Bo , Feng Kun
Published: May 2020

The effects of different zero-holding quenching temperatures on the tempering microstructure, mechanical properties and wear resistance of 40Cr were studied. The results showed that the microstructure of 40Cr was tempered sorbite and a small amount of unmelted ferrite after quenching at 850 °C and tempering at 550 °C for 2 h. Tempered sorbite was obtained after quenching at 880 °C～910 °C and tempering at 550 °C for 2 h. With the increasing of quenching temperature at zero holding temperature, the tensile strength and yield strength of 40Cr increased, while the elongation and impact toughness decreased. With the decreasing of impact test temperature, the ballistic work of 40Cr decreased gradually, and decreased fastest between 0 °C～-20 °C. 40Cr had the best impact performance after quenching at 850 °C and tempering at 550 °C for 2 h. 40Cr had the smallest wear loss after quenching at 880 °C and tempering at 550 °C for 2 h. Its wear marks were smooth, and had the shallowest furrows and ridges.
Effect of Ferritic Hot Rolling Process on Microstructure and Properties of IF Steel
Authors: Chang Wen Gao , Yu Wei , Yang Huan , Man Zeng Qiang , Cao Yun Fei
Published: May 2020

The effect of ferritic hot rolling process on microstructure and properties of Ti microalloyed IF steel was investigated. The hot rolling-coiling, cold rolling and continuous annealing processes of ferritic zone were physically simulated. The influence of thermal deformation (finishing rolling temperature, coiling temperature) on the structure, texture and forming properties of Ti-If steel was studied through tensile test, EBSD, XRD and other analytical methods. The results showed that the recrystallization occurred after hot rolling and coiling in the ferritic region. Weak α-fiber and weak γ-fiber were obtained in the central layer of hot rolling plates, and the strength of γ-fiber was higher when finished rolling at low temperature. α-fiber and weak γ-fiber were strengthened after cold rolling. After annealing, the α-fiber was weakened and the γ-fiber was strengthened, and the γ-fiber became the main texture. The larger and more uniform grain size and better mechanical properties were obtained by IF steel finished rolling and coiling at high temperature and after continuous annealing, reaching yield strength of 106 MPa, tensile strength of 297 MPa, elongation rate of 52%, n value of 0.26 and r value of 2.3. The hot rolling texture is hereditary. If the more γ-fiber is formed after hot rolling, the more γ-fiber recrystallization texture is formed after cold rolling and annealing.
Effect of Composition System on Microstructure and Properties of 1000-MPa Grade Cold Rolled DPSteel
Authors: Zhao Xiao Long , Zhao Dong Liang
Published: May 2020

1000 MPa grade cold-rolled duplex steel with 5 component systems was trial-produced in the laboratory. After hot rolling, pickling and cold rolling, the test steel was simulated continuous annealing on Gleeble-3800 thermal simulator. The microstructure and properties of 5 kinds of experimental steels after simulated annealing were analyzed. The results show that C and Mn elements are the basic alloy systems of all duplex steels. In the case of low Si element, the C element content of the 1000 MPa grade dual phase steel should be 0.15 % or higher, and the Mn element content should be higher than 1.8 %. Si element increased to the A3 point, while the amount of austenite was less in the two-phase region during annealing, and the volume fractionof martensiteafter the rapid cooling is insufficient; Nb element is a high-efficiency fine-grain strengthening element, which greatly improvedthe uniformity of the steel species. The fine-grained martensite islands have enhance the tempering stability of martensite and thereby to reduce the adverse strength effect from over-aging temperature.
Investigation on the Microstructure and Mechanical Properties of T23 Steel during High Temperature Aging
Authors: Shi Bao Liang , Zhang Chao , Tang Yao Wen , Wei Guo Jie , Li Yan , He Cheng , Xu Kai
Published: May 2020

The changes of the microstructure and mechanical properties of T23 steel were investigated during high temperature aging at 625 °C up to 3000 h. The results showed that the bainitic lath microstructure first decreased and then totally disappeared with the increase of aging time, the size of the carbides gradually increased and the recovery occurred after aging for 1000 h. The contents of W, Mo elements in the matrix after aging for 3000 h were remarkably decreased by 27.6% and 45% compared with the as-received state. However, no M6C carbides formed in spite of the obvious desolution transformation of W, Mo. Both the yield strength and the tensile strength at room and high temperature were decreased with the increase of aging time at 625 °C, and the tensile strength at high temperature after aging for 3000 h exhibited the largest of decline compared with the as-received state. The main reasons for the decrease of the mechanical properties related to the microstructure variations, such as the size increase of the M23C6 carbides, the dissolution of the bainite lath microstructure and the occurrence of the recovery. Meanwhile, the desolution of W, Mo elements plays an important role in the decrease of the mechanical properties.
Applications of Nickel-Based Alloy for Oil Country Tubular Goods
Authors: Liu Le , Feng Chun , Li Rui Zhe
Published: May 2020

With the development of the petroleum industry, more and more high temperature, high pressure and high corrosion wells have appeared. In order to adapt to the harsh environment of oil fields, nickel-based alloy oil country tubular goods have been developed and applied in the world. Nickel-based alloy oil country tubular goods have excellent high-temperature performance and good corrosion resistance, but their manufacturing and processing are difficult and the cost is high, which restricts their large-scale application and development in the petroleum industry. In this paper, the microstructure and properties of the commonly used nickel-based alloys were analyzed, the corrosion mechanism in the acidic environment and the pipe processing technology was discussed.
Analysis of Tensile Properties of N80Q Steel and 80SH Steel
Authors: Chen Yang , Wang Hang , Yang Shang Yu , Wei Wen Lan , Luo She Ji , Han Li Hong
Published: May 2020

During heavy oil production, the performance of casing varies with temperature in the service environment. The tensile test of N80Q Steel and 80SH Steel were carried out to evaluate the mechanical properties during the service. The results indicated that the grain size of 80SH steel was relatively uniform and the grain boundary was relatively obvious compared with N80Q steel. A qualitative analysis was performance by relating the tensile properties with different temperature. The results showed that the yield strength, the tensile strength and elongation of N80Q and 80SH steels decreased with increasing temperature, but the degree of decline was limited. The observation of the tensile fracture revealed that the characteristics of the radiation zone of N80Q steel were obvious compared with 80SH steel at 20°C.
Preparation and Magnetic Properties of Fe@SiO2 Soft Magnetic Composites
Authors: Feng Shuai , An Yan , Wang Zong Xiang , Sun Kai , Fan Run Hua
Published: May 2020

In this work, the insulating SiO2 was coated successfully on the surface of reduced iron particles by a sol-gel method to decrease the core loss at low frequency. The scanning electron microscope images and elements analysis confirm that the surface of iron powders particles were covered by a thin insulating layer in the form of uniform core-shell structure. The samples were annealed at 400 °C in N2 atmosphere to obtain better magnetic properties. The annealed SMCs with 10 mL/h dropping rate of TEOS have optimum magnetic properties with low core loss Ps of 280.89 W/kg and high saturation magnetic flux density Bs of 1.038 T at 1000 Hz.
Microstructure and Properties of Co@RGO/Cu Composites by One-Step In Situ Reduction Method
Authors: Liu Shao Hui , Zhao Yu , Ran Xu
Published: May 2020

In order to improve the interfacial bonding between graphene and copper and improve the dispersibility of graphene in the copper matrix, a novel method was used to prepare graphene. Firstly, graphene oxide (GO) was prepared by the modified Hummer's method, and then the reduced graphene oxide-supported cobalt nanoparticle composite powder (Co@RGO) was prepared by one-step in-situ reduction method. The fabricated materials were mixed with copper powder to obtain various volume fractions. The powder mixture was subjected to compression and discharge plasma sintering (SPS) to prepare a bulk copper-based composite material. The microstructure and its comprehensive properties were studied by SEM, TEM, XRD, FTIR and Raman. The results show that the agglomeration of graphene can be effectively inhibited after the cobalt nanoparticles supported on the graphene surface. The proper amount of Co@RGO could be uniformly dispersed in the copper matrix. The composite material showed a high electrical conductivity (>86% IACS), and the Vickers hardness also increased by about 30% compared with pure copper.
Effect of Simulated Seawater on Flexural Property of Corn Straw Fibers Reinforced Polypropylene Composites
Authors: Gu Nian Liang , Wang Jian Rong , Chu Cai Xia , Chen Juan , Li Ke
Published: May 2020

In this paper, the effect of simulated seawater on properties of corn straw fibers (CSF) reinforced polypropylene composites was studied. Firstly, CSF was modified with nano-TiO2 particles, and then the modified CSF reinforced polypropylene (PP) composite was prepared. The flexural property and the microstructure of the composites before and after soaking simulated seawater for 21 days were investigated. The results showed that the simulated seawater in short-term immersion could play a role in plasticizing interface and improve the flexural property of CSF/PP composite. After 21 days of simulated seawater immersion, the flexural strength of CS/PP was increased by 18.00%. The modification of TiO2-CSF could improve the flexural property of CSF/PP composite. When the addition of TiO2 was 4 wt.%, the flexural strength reached 44.91 MPa, increased by 17.54% compared with that of unmodified composite.
Effect of Air Oxidation Treatment on Interficial Properties of Carbon Fibers
Authors: Wang Shi Hui , Yao Li Li , Jin Jun Hong , Li Guang , Yang Sheng Lin
Published: May 2020

In this work, low temperature air oxidation treatment for carbon fiber sized by epoxy was performed and the surficial chemical changing, the sizing and fiber strength retention, as well as the adhesion properties between CFs and Nylon resin were characterized. The surficial modification effects from the air oxidation were also compared with other treatment such as electrochemical processing. It has been found the carbon fiber could obtained more polarized functional groups in the surface to promise better compatibility with thermoplastic matrix, and maintain enough sizing protection and fiber strength
Effect of Graphene Content on Microstructure and Properties of Gr/Cu Composites
Authors: Zhang Yu , Li Yan , Li Yan Chun , Song Mei Hui , Zhang Xiao Chen
Published: May 2020

Graphene(Gr) reinforced copper matrix composites(Gr/Cu) were prepared by powder metallurgy process, and the effects of graphene content on microstructure and properties of the composites were investigated. The microstructure, density, hardness and electrical conductivity of the composites were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), density measurement, hardness tester and conductivity meter. The microstructure results show that with the increase of graphene content, the number of pores in the composites increased continuously, and the interface of the composites was well bonded. It was observed that there was no cracking and obvious interfacial reaction. However there were a lot of dislocations and twins in the matrix Cu, which might be the main reason for the decrease of the conductivity of the composites. The results of the composites’ properties revealed that with the increase of graphene content, the density and electrical conductivity of the composites decreased, the hardness increased first and then decreased. When the mass fraction of graphene was 0.5%, the maximum HBW was 175, and when the mass fraction of graphene was 3%, the density and conductivity of the composites decreased by 12% and 45% respectively, compared with pure copper.
High Temperature Stability of Zirconium Tungstate
Authors: Zhai Ping , Duan Xiao Feng , Chen Da Qian
Published: May 2020

In this paper, zirconium tungstate ceramic with negative thermal expansion coefficients was prepared from zirconium oxide and tungstic acid by solid phase synthesis and high temperature quenching technique with a sintering temperature of 1200 °C. The phase structure of the material was determined by X ray and the thermal expansion coefficient was measured by dilatometer, while the TG-DTA analysis of the prepared material was also carried out. The results showed that zirconium tungstate with high purity could be obtained by rapid chilled while fired at 1200 °C. The coefficient of thermal expansion at 300 °C was minus 8.5413 × 10-6K-1, which is identical with the theoretical value. The thermal expansion coefficient of the material was negative fired lower than 750 °C, while it was positive fired higher than 750 °C, and this indicates that the decomposition temperature of zirconium tungstate is about 750 °C.
Preparation of Titanium Alloy Powder by Plasma Rotating Electrode Process
Authors: Li Yan Chun , Song Mei Hui , Zhang Xiao Chen , Zhang Wei Jun , Li Yan , Zhang Yu
Published: May 2020

Titanium alloy powders were prepared from titanium rods by plasma rotating electrode process (PREP). The effects of powder preparation technology on the morphology and properties of titanium alloy powders were studied by laser particle size analyzer, scanning electron microscope (SEM), X-ray diffraction, powder comprehensive property tester and oxygen nitrogen analyzer. The results shown that the titanium alloy powder prepared by PREP had uniform particle size distribution, sphericity >93% and oxygen content <1000 ppm. For TA1 powder, the phase’s structure was mainly composed of HCP-α phase, while the TC4 powder mainly composed of α' phase. During the preparation process, the particle size and sphericity of the alloy powder increased with the increase of electrode speed. The smaller the particle size and the higher the sphericity of the alloy powder, the larger the compacting density and bulk density, but the powders fluidity became worse. At the same time, the oxygen content of the titanium alloy powder increased with the decrease of the particle size, while the nitrogen content was not affected by the powder size. The oxygen content of the titanium alloy powder increased as the particle size became smaller, and the nitrogen content was not affected by the powder size.
Effect of Nano Sodium Titanate/ Potassium Titanate Whisker on Tribology Behavior of Brake Materials
Authors: Guo Ke , Zhang Zhi Qiang , Pei Zhong Zheng , Xu Jie , Feng Yi Fan
Published: May 2020

Here we developed a hot-pressed molded resin-based brake pad material reinforced by a nano sodium titanate whisker in comparison with nano potassium titanate whisker. The effect of the whiskers on the tribology behavior was investigated. Though nano sodium titanate whisker reinforced brake material showed higher porosity (+12.29% averagely) and lower hardness (-25.8% averagely) caused by the impurities, it exhibited improved ability in stabilizing the friction coefficient and enhancing 25.5%, 31.1%, 25.9% higher wear resistance, when the volume contents of whisker are 7.5%, 15% and 22.5%, respectively, compared to the nano potassium titanate whisker reinforced brake material. The wear mechanisms of the nano sodium titanate whisker reinforced brake materials were determined as embedded debris, delaminated crater, moderate layers transfer, uniform furrows, primary plateaus and secondary plateaus in similar size, indicating a main wear form of abrasive wear instead of adhesive wear.
Microstructure and Mechanical Properties of GMAW Welded Joints Er-Containing Aluminum Alloy
Authors: Guo Hao Zhen , Cui Li , Huang Hui , Guo Xiao , He Ding Yong
Published: May 2020

This present work explored the welding process of gas metal arc welding for 4mm 5E61 Er-containing aluminum alloy, and then analyzed the microstructure and mechanical properties of the welded joint. The results demonstrated that when the welding current was 160A-220A, the welded joint penetration depth range was 5.75mm to 6.72mm, the melting width ranging from 9.68mm to 11.61mm. When the arc voltage increased from 17.5V to 22.5V, the penetration depth of the welded joint reduced from 6.95mm to 5.57mm, and the melting width ranged from 6.64mm to 11.86mm. When the welding current was 170A, the arc voltage was 17.5V, and the welding speed was 10mm/s. In the third case, a fully penetrated welded joint can be obtained and the joint strength was the highest value. The yield strength reached 192 MPa, the tensile strength can be 301 MPa, and the fracture location occurred in the HAZ. The weld zone of the welded joint mainly consist of the equiaxed dendrites size of 50 μm. The micro-hardness of the weld zone was lower than that of the base metal, and there was no obvious softening phenomenon in the heat affected zone.
Preparation and Numerical Simulation of Heat Transfer Performance for Methyl Palmitate-Methyl Stearate Binary Eutectic Mixture/Expanded Graphite Composite Phase Change Material
Authors: Chi Bi Chuan , Yao Yan , Cui Su Ping
Published: May 2020

The binary eutectic mixtures of fatty acid esters are promising phase change materials for energy storage application. However, the low thermal conductivity which is a common problem for organic phase change materials restricts their further and better applications. In order to solve the problem, a novel composite phase change material (CPCM) was prepared in this research by using methyl palmitate-methyl stearate (MP-MS), a typical binary eutectic mixture of fatty acid esters, as phase change material and expanded graphite (EG) as heat transfer enhancer. The heat transfer performance of MP-MS/EG CPCM was numerical simulated by finite element analysis software ABAQUS. Numerical simulation results revealed that EG could notably enhance the heat transfer performance of MP-MS eutectic mixture. The heat transfer rate and phase change reaction rate of MP-MS/EG CPCM were 14 times and 3 times that of MP-MS eutectic mixture, respectively.
Numerical Simulation of Ni-Cu Alloy Dendrite Growth with Boundary Heat Flux
Authors: Wang Ming Guang , Jiang Shan
Published: May 2020

Evolution of the dendrite growth and the distribution of concentration and temperature fields in a Ni-0.4083 at.% Cu alloy was simulated. The dendrite morphology was greatly affected by boundary conditions. The result shows that the solid/liquid interface of dendrite was most instable and grew most fast under extraction boundary condition. The re-calescence occurred under the extraction boundary condition and Zero-Neumann boundary condition, but not under the heating boundary condition.
Cord Blood Low-Density Granulocytes Correspond to an Immature Granulocytic Subset with Low Expression of S100A12
Authors: Weinhage Toni , Kölsche Tristan , Rieger-Fackeldey Esther , Schmitz Ralf , Antoni Anne-Charlotte , Ahlmann Martina , Foell Dirk , Wittkowski Helmut
Published: May 2020

Although substantial progress has been achieved concerning neonatal sepsis, its lethality remains considerably high, and further insights into peculiarities and malfunctions of neonatal immunity are needed. This study aims to contribute to a better understanding of the role of human neonatal granulocyte subpopulations and calgranulin C (S100A12). For this purpose, we gathered 136 human cord blood (CB) samples. CD66b+ CB low-density granulocytes (LDG) and CB normal-density granulocytes were isolated and functionally and phenotypically compared with healthy adult control granulocytes. We could identify CB-LDG as CD66bbright CD64high CD16low CD35low CD10low S100A12med-low and, based on these markers, recovered in whole CB stainings. Consistent with flow cytometric findings, microscopic imaging supported an immature phenotype of CB-LDG with decreased S100A12 expression. In CB serum of healthy neonates, S100A12 was found to be higher in female newborns when compared with males. Additionally, S100A12 levels correlated positively with gestational age independently from sex. We could solidify functional deficits of CB-LDG concerning phagocytosis and generation of neutrophil extracellular traps. Our study reveals that previously described suppressive effects of CB-LDG on CD4+ T cell proliferation are exclusively due to phagocytosis of stimulation beads used in cocultures and absent when using soluble or coated Abs. In conclusion, we characterize CB-LDG as immature neutrophils with functional deficits and decreased expression and storage of S100A12. Concerning their cross-talk with the adaptive immunity, we found no direct inhibitory effect of LDG. Neonatal LDG may thus represent a distinct population that differs from LDG populations found in adults.
Early T Cell Activation Metrics Predict Graft-versus-Host Disease in a Humanized Mouse Model of Hematopoietic Stem Cell Transplantation
Authors: Hess Nicholas J. , Hudson Amy W. , Hematti Peiman , Gumperz Jenny E.
Published: May 2020

Acute graft-versus-host disease (GVHD) is a frequent complication of hematopoietic transplantation, yet patient risk stratification remains difficult, and prognostic biomarkers to guide early clinical interventions are lacking. We developed an approach to evaluate the potential of human T cells from hematopoietic grafts to produce GVHD. Nonconditioned NBSGW mice transplanted with titrated doses of human bone marrow developed GVHD that was characterized by widespread lymphocyte infiltration and organ pathology. Interestingly, GVHD was not an inevitable outcome in our system and was influenced by transplant dose, inflammatory status of the host, and type of graft. Mice that went on to develop GVHD showed signs of rapid proliferation in the human T cell population during the first 1–3 wk posttransplant and had elevated human IFN-γ in plasma that correlated negatively with the expansion of the human hematopoietic compartment. Furthermore, these early T cell activation metrics were predictive of GVHD onset 3–6 wk before phenotypic pathology. These results reveal an early window of susceptibility for pathological T cell activation following hematopoietic transplantation that is not simply determined by transient inflammation resulting from conditioning-associated damage and show that T cell parameters during this window can serve as prognostic biomarkers for risk of later GVHD development.
Novel use of the endobronchial ultrasound through esophagus (EUS-B): Diagnosis of thyroid lesions
Authors: Tamburrini Mario , Thakare Parikshit , Zuccon Umberto
Published: May 2020

There is paucity in literature on the use of endobronchial ultrasound through esophagus (EUS-B) for the diagnosing thyroid gland lesions. We report the first case of colloid goiter diagnosed using EUS-B- FNA technique. A 77-year-old man presented with ophthalmic symptoms and an incidental finding of lung nodule on chest x-ray. The computed tomography of thorax revealed a left upper lobe nodule and an oval shaped left paratracheal lesion near left pole of thyroid gland. EUS-B- FNAC was performed which lead to the diagnosis of colloid goiter.