2022 Vol. 37, No. 3

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Materials Research
Experimental Study on Deep Notch Fracture Characteristics of Q420qE Bridge Steel
GONG Xuhui, GAO Zhenpeng, WU Songlin, NIU Jiajia
2022, 37(3): 1-4.
[Abstract](89) [PDF 1810KB](7)
Abstract:
Deep notch wide plate tensile test and conventional tensile test are conducted on 20 mm-thick Q420qE steel in temperature range of -80~20℃. Results indicate that with the decreasing temperature, the fracture strength Rf increases, the fracture strain ef remains almost the same, and the deep notch fracture strength Rn decreases. A modified Neuber formula is proposed to describe the relationship between Rn, Rf, ef and the temperature. The deviation between Rn calculated by the proposed formula and tested by deep notch wide plate tensile test is within ±5%, indicating that for deep notch wide plate tensile test, the decrease of temperature may increase the concentration of stress and strain due to the presence of the deep notch.
Impact of Trace Cu Addition on Microstructure, Mechanical Property and Corrosion Behavior of TA10 Alloy
YANG Yong, WANG Binbin, LI Yanjie, LUO Liangshun, HUANG Haiguang, WANG Liang, SU Yanqing, GUO Jingjie, FU Hengzhi
2022, 37(3): 5-12,20.
[Abstract](73) [PDF 10770KB](13)
Abstract:
The effects of (0.5%~2.5%, w) Cu addition on the microstructure, mechanical property and corrosion behavior of TA10-based alloys are studied. Scanning electron microscopy (SEM) and optical microscopy (OM) are used to study the microstructure of the alloys, and the X-ray diffraction (XRD) is adopted to identify the phase composition. The electrochemical measurements and the static immersion tests are employed to study the corrosion performances of the alloys. After obtaining the alloy with the optimal chemical compositions, its corroded surface morphology is observed by the atomic force microscope (AFM). Results signify that with the increase of Cu content, the matrix structure of TA10 alloy is continuously refined. When the Cu addition is 2.5%, the hardness of the alloy is the maximum. When the Cu addition is in the range of 1.5%~2.0%, the alloy has good corrosion resistance. The alloy with 0.5% Cu presents the best corrosion resistance.
Comparison of Properties and Microstructures between Al-Cu-Mg-Ag Alloy and ZL205A Alloy
SUN Jianjun, WANG Pengyun, XIE Shufeng, ZHANG Fanxing, WANG Zhenghong
2022, 37(3): 13-20.
[Abstract](176) [PDF 9381KB](12)
Abstract:
Al-Cu-Mg-Ag aluminum alloy and ZL205A aluminum alloy are prepared by semi continuous casting. The flow properties, tensile properties at room and high temperatures, tensile fracture morphologies, intergranular corrosion depths and microstructures of the two alloys are compared and analyzed. The results show that when the pouring temperatures are 720℃ and 740℃, the flow properties of Al-Cu-Mg-Ag aluminum alloy are better than those of ZL205A aluminum alloy. At room temperature, 150℃, 200℃ and 250℃, the strengths of Al-Cu-Mg-Ag aluminum alloy are better than those of ZL205A aluminum alloy, and with the increase of temperature, the drop of strength of Al-Cu-Mg-Ag aluminum alloy is slighter than that of 205A aluminum alloy. The room temperature elongations of the two alloys are almost the same. The intergranular corrosion depth of Al-Cu-Mg-Ag aluminum alloy is in the range of 182-246 μm, lower than 274-337 μm of that of the ZL205A aluminum alloy. The width of precipitate free zone of Al-Cu-Mg-Ag aluminum alloy is narrower than that of ZL205A aluminum alloy.
Precipitation Analysis of Nanoclusters in Lamellar Structured Titanium Alloy
WU Xiaofei, WU Yukun, CHEN Jieming, JIANG Peng, YIN Yanchao, PENG Hui
2022, 37(3): 21-25.
[Abstract](97) [PDF 9489KB](8)
Abstract:
The α phase globularization is locally found in lamellar structure of Ti-5Al-2Zr-1Sn-1Mo-1V alloy after being treated at 950℃. Besides, clusters are found when the alloy is heat treated at different temperatures. The samples with clusters are accurately prepared by focused ion beam (FIB). The morphologies are observed and diffraction pattern is analyzed by TEM. The results show that nanoclusters in lamellar structure are composed of several Sn single crystal particles with the size of less than 100 nm.
Study on Effect of Zirconium Dioxide Coating on Improving High Temperature Resistance of Iron-cobalt Absorbent
HONG Yuehui, ZHUANG Haiyan, YE Zhimin, CHEN Xiang, YANG Lieji
2022, 37(3): 26-34,68.
[Abstract](84) [PDF 15242KB](9)
Abstract:
The sol-gel method is used to prepare FeCo@ZrO2 absorbent by the combination of zirconia and FeCo. Vector network analysis is used to characterize the electromagnetic parameters and absorbing performance of FeCO@ZrO2 before and after high temperature treatment. The results show that the dielectric constant of FeCo@ZrO2 absorbent modified by coating is significantly reduced. The impedance matching characteristics and absorbing performance of the FeCo@ZrO2 absorber are improved. The modified FeCo@ZrO2absorber still has significant absorbing performance after high temperature treatment, and its reflectivity simulation curve remains below -10 dB at 7-9 GHz.
Failure Analysis and Research of Tantalum Powder for Capacitor
LI Zhongxiang, ZHANG Jiankang, CHEN Xueqing, DAI Yanming
2022, 37(3): 35-38.
[Abstract](89) [PDF 5596KB](11)
Abstract:
The reasons for large leakage current or the breaking down of the single tantalum anode block of capacitor are analyzed by using the scanning electron microscopy, and the main reason is that the local inclusions cause the abnormal growth of the oxide film, resulting in the discontinuity of the local tantalum oxide film on the surface of the particles, therefore, a large number of electrons pass through the leakage and even leads to the breakdown of the anode. The foreign body appearing in the tantalum anode block is the carbide inclusion of tantalum in the raw material of tantalum ingot, and the carbide inclusion of tantalum has high melting point and acid erosion resistance. In the subsequent treatment of the tantalum powder, the carbide inclusion of tantalum cannot be removed and remains in the tantalum powder. Backscatter electron imaging can be applied to tantalum sample detection.
Material Application
Morphology Effects of TiO2 Mediated Layer on Electrolytic Chlorine Evolution Performance of Ru-Ir Oxide Electrodes
DUAN Tigang, MA Li, WU Zhengjiang, XIN Yonglei, GAO Xianze, XU Likun
2022, 37(3): 39-44.
[Abstract](62) [PDF 8645KB](12)
Abstract:
TiO2 mediated layers with various morphologies such as nanosheets and nanowires have been realized through the alkaline hydrothermal method to improve the electrochemical performance of Ru-Ir oxide electrodes. After introducing the TiO2 mediated layers, the electrode cracking morphology turns to the hierarchical structures with nanosheets and nanowires, and the cracks on the electrode surface disappear. Linear sweeping voltammetry analysis indicates that the chlorine evolution potential of electrode reduces from 1.171 V (vs. SCE) to 1.162 V (vs. SCE), and that the chlorine evolution polarizability decreases from 0.516 V to 0.454 V when the electric current densities are 2 mA·cm-2 and 20 mA·cm-2. The voltammetry charge calculation shows the amount of voltammetric charge for TiO2-mediated Ru-Ir oxide electrode increases to 18.3 mC·cm-2, which is 4.78 times as much as that of Ti/Ru-Ir electrode (3.83 mC·cm-2). Meanwhile, the charge transfer impedance decreases. Introducing the TiO2 mediated layers with various morphologies can improve the electrochemical activity of electrode and enhance the electrocatalytic chlorine evolution ability.
Development of High Fire Resistant Composites Grating for Ship and Ocean Engineering
LIU Qiang, ZHAO Yu, ZHANG Xinggang, SHI Xiao
2022, 37(3): 45-51.
[Abstract](80) [PDF 11329KB](13)
Abstract:
The phenolic pultruded grating which can be used in ship and ocean engineering is produced. The effects of mesh number, specific gravity and functional diluent of porcelain aggregate on the interfacial adhesion between resin and glass fiber in marine composite gratings are studied. When 30% ceramic aggregates with particle size of 6.5 μm and 10% functional diluents are added in the system, the failure load strength of the grating before fire is 368.76 MPa, and the structural fire integrity of the grating, fired for 1 h according to the standard temperature rise curve, reaches the level of L2.
Study on Technology of Reinforcing Layer Shell of Titanium Alloy Precision Casting with Complex Structure
CHENG Yazhen, YAN Feihao, YANG Guang, LIU Yinqi, SUN Hongzhe, TIAN Yongwu
2022, 37(3): 52-56.
[Abstract](142) [PDF 7226KB](16)
Abstract:
The performances of shells by three different shell making processes are analyzed through studying wet strength, fired strength and permeability of specimens. Titanium alloy castings with complex structures have been produced by the above processes, among which, carbon fiber shell making process is the most suitable for mass production of reinforced layer shell of titanium alloy precision castings with complex structures.
Corrosion Factor Analysis of Heat Exchange Tubes of Open Rack Vaporizer
LIU Jingjun, ZHANG Dawei, WANG Jiankun, LI Shuyi, MA Yang
2022, 37(3): 57-60.
[Abstract](116) [PDF 3616KB](9)
Abstract:
At present, the long-term protection measure for the heat exchange tubes of open rack vaporizers (ORV) is to prepare aluminum and its alloy coatings on their surfaces. Due to the long-term exposure to the marine environment, the aluminu-mbased coating on the surface of the heat exchange tube will appear pitting, bulging, shedding, and thinning, which may threaten the safe and efficient operation of the equipment. Here, the factors that affect the corrosion of ORV heat exchange tubes are analyzed, such as sand content of seawater, flow rate of seawater, ion species, and PH value of seawater, etc. The results can provide certain theoretical support for the corrosion mechanism research, life evaluation of protection layer, equipment status monitoring, and daily operation and maintenance of the heat exchange tubes.
Numerical Simulation of Inner Flow of B10 Copper Alloy Elbow Based on FLUENT
ZHOU Tiezhu, YU Yan, ZHENG Congfang, YUAN Wei, FU Liguo, ZHAO Guochao
2022, 37(3): 61-68.
[Abstract](84) [PDF 8167KB](6)
Abstract:
The fluid model of seawater for elbow is established based on FLUENT, the influence of weld reinforcement, velocity, bending radius and the distance of straight pipe on the inner flow for the elbow is analyzed by the numerical simulation method. The primary and secondary relationship of various factors on the inner erosion corrosion of elbow is analyzed by range analysis through orthogonal experiment.
Influence of Molding and Sintering Process on Electrical Property of Tantalum Anode
XU Ninghui, ZHU Li, WANG Juan, NIU Weidong
2022, 37(3): 69-74.
[Abstract](30) [PDF 6233KB](5)
Abstract:
The FTA500 grade tantalum powder with the capacity of 50 000 μF·V/g is chosen to explore the effect of the molding and sintering processes on electrical properties of tantalum anode. The results show that the opening ratio and capacity of tantalum anode block decrease with the increase of pressing density. When the pressing density is 5.00 g/cm3, the leakage current coefficient of anode block is the lowest. With the increase of sintering temperature, the sintering density increases, the specific capacitance and the leakage current coefficient decrease, the loss of tantalum anode increases, the volume shrinkage increases, and the breakdown voltage increases.
Welding Technology
Study on Properties and Microstructure of Surfacing Welding Joint of 317L/FH40 Clad Steel Plate
ZHAI Weiguo, REN Jiangyi, DENG Guangping
2022, 37(3): 75-81,92.
[Abstract](63) [PDF 9214KB](7)
Abstract:
The 317L/FH40 composite steel plate with thickness of 8 mm+48 mm is welded by cladding welding (repair welding) using the optimized process parameters, and then the post-welding heat treatment is carried out. The mechanical properties and microstructure of the joint are tested. The results show that the test results of mechanical properties of 317L/FH40 composite plate surfacing joints can meet the requirements of relevant standards and the needs of practical engineering. The microstructure analysis results show that the grain size grows in the heat affected zone of 317L cladding steel, and the microstructure changes in the heat affected zone of FH40 base steel. The results of microhardness test show that the hardness of the joint in each region has little fluctuation, but the hardness of different regions is different, increasing or decreasing in local regions. The results of intergranular corrosion test show that there is no intergranular corrosion tendency in the cladding welding seam.
Analysis on Welded Joint Properties of FH40 + 317L Clad Plates
ZHU Guanpeng, GAO Zhenpeng, GONG Xuhui
2022, 37(3): 82-87.
[Abstract](50) [PDF 5865KB](7)
Abstract:
Experiments are carried out for the welding of FH40 steel + 317L stainless steel clad plates through the selection of welding materials and the design of welding procedure. The microstructures of the joints and the morphologies of the impact fractures are analyzed. It shows that the welding procedure could be divided into three sections, including base layer welding, transition layer welding and clad layer welding. The welding joint performs a good mechanical property matching with the base metal. The impact results of the different places from the clad side are basically the same. The impact fracture at -60℃ presents a ductile fracture morphology, and no martensite microstructure occurs in the transition layer.
Study on Interface Characterization and Mechanical Properties of TA2/3A21/AZ31B Composite Plate
LIU Linjie, SUN Hao, FAN Keshe, ZHU Lei, PANG Guoqing
2022, 37(3): 88-92.
[Abstract](117) [PDF 5300KB](14)
Abstract:
TA2/3A21/AZ31B three-layer composite plate is prepared by explosive welding. The interface, microstructure and mechanical properties of the composite are tested and analyzed by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and universal testing machine. The experimental results show that the tensile strength, yield strength and elongation after fracture of the TA2/3A21/AZ31B composite prepared by one-time explosive welding are about 303 MPa, 233 MPa and 9.7%, respectively. The special wavy structures from explosive welding are formed at the titanium/aluminum and aluminum/magnesium interfaces. The thickness of Ti-Al diffusion layer at the titanium/aluminum interface is about 5 μm, and the thickness of the Al-Mg diffusion layer at the aluminum/magnesium interface is about 30 μm. The shear strengths of the Ti-Al and Al-Mg diffusion layers are 132.6 MPa and 116.3 MPa, respectively. Compared with TA2/AZ31B composite, mechanical property of the TA2/3A21/AZ31B composite is greatly improved.
Review
Low Cost Technology and Application of Titanium for Marine Seawater Pipeline in the USA
ZHAO Yanying
2022, 37(3): 93-96.
[Abstract](55) [PDF 4923KB](20)
Abstract:
With the improvement of the requirements for corrosion resistance and high reliability of ships, the demand for titanium materials with outstanding corrosion resistance is becoming more and more urgent, but the high cost has always been one of the important factors restricting the extensive application of titanium and titanium alloys in ship domain. Therefore, a large number of studies have been carried out on the low cost technology of titanium at home and abroad, and some research findings have been applied. However, most of the relevant findings are not systematic. Here is systematically introduced the low cost technology of marine titanium in the USA from the aspects of material manufacturing and application, which will provide a systematic low cost technical reference for the application of titanium materials in the field of marine seawater pipeline.
Experience Exchange
Thickness Measurement System Design of Radar AbsorbingCoating in a Composite Stealth Coating
WANG Dongfeng, ZHANG Wei, ZHANG Tao
2022, 37(3): 97-100.
[Abstract](107) [PDF 4074KB](14)
Abstract:
For the structural characteristics of the "radar + infrared" composite stealth system and the magnetization characteristics of the radar absorbing coating, the magnetic thickness measurement model for the radar absorbing coating in a composite stealth coating is established and the thickness measurement algorithm analyzed. It is found that when the sum of the thicknesses of the infrared coating and a certain primer in the composite stealth system is much smaller than the thickness of the air coating, the magnetic thickness measurement can ignore the influence of the thicknesses of the infrared coating and the primer, and that the thickness of the radar absorbing coating can be directly measured by using the electromagnetic characteristic relationship that the magnetic force is proportional to the thickness of the radar absorbing coating. Besides, a magnetic thickness measurement sensor is designed and the magnetic force measurement test is carried out. The results show that the magnetic thickness measurement system has a simple structure and accurate measurement results.

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