2022 Vol. 37, No. 2

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Materials Research
Study on Superelastic Anisotropy Parameters and Numerical Calculation of Columnar-grained Cu-Al-Mn Shape Memory Alloy
WANG Han, SHI Bo-wen, NIU Jian-min, LIU Ji-li
2022, 37(2): 1-9.
[Abstract](99) [PDF 8711KB](18)
Abstract:
Based on the conversion relationship between the off-axis engineering elastic constant and the positive-axis engineering elastic constant of the single-layer plate, the parameters are deduced, and the calculation of superelastic anisotropy parameters at any angle of the alloy is realized. Then the superelastic stress-strain curves at any angle of the alloy are simulated by a finite element user subroutine. The simulation results agree well with the experimental data, which can provide guidance and reference for the simulation calculation of the anisotropic properties of columnar-grained structure alloys.
Effect of Nitrogen on Microstructure and Toughness of Coarse Grain Heat Affected Zone in Vanadium Microalloyed Steel
SHI Zhong-ran, PAN Tao, WANG Rui-zhen, WANG Dong-ming, ZHAO He-ming, LUO Xiao-bing, CHAI Feng, YANG Cai-fu
2022, 37(2): 10-18.
[Abstract](60) [PDF 12386KB](9)
Abstract:
Microstructures and toughness of coarse grain heat affected zones(CGHAZ) in experimental steels with different nitrogen contents are studied by welding thermal simulation.Resultsindicate that with the increase of nitrogen content, CGHAZ microstructure changes from grain boundary ferrite, bainite and side lath ferrite to acicular ferrite, polygonal ferrite and a small amount of bainite, with the ferrite grains refined. The ductile-brittle transition temperature(FATT50) of CGHAZ steel decreases first and then increases, meanwhile the yield strength rises. When the nitrogen content increases from 0.004 4% to 0.009 4%, the effective grain size decreases and the FATT50 of CGHAZ decreases. When the nitrogen content increases from 0.009 4% to 0.019 0%, the combined influence of solid solution nitrogen and yield strength increment on FATT50 is greater than that of grain refinement, leading to the increase of FATT50.
Effect of Rare Earth Element Nd on Microstructure and Properties of High Aluminum Magnesium Alloy
HAN Qian, ZHENG Meng, WANG Zhi-hua, FENG Wen-bin, YU Miao-miao, ZHANG Mei-li, DAI Wei-li
2022, 37(2): 19-23.
[Abstract](91) [PDF 4488KB](22)
Abstract:
Effects of rare earth element Nd content on microstructure and mechanical properties of Mg-10 Al-Zn alloys are stud-ied.Resultsshow that after adding rare earths, the alloys are mainly composed of a-Mg, β-Mg17Al2 and Al2Nd phases, and that Al2Nd phase distributes in the shape of flakes. When adding content of Nd is 2.5%,the maximum tensile strength and elon-gation are 130 MPa and 4.37%. Fracture analysis shows that the rare earth magnesium alloy is plastic fracture.
Correlation Analysis of Deformation Characteristics and Stress-strain Constitutive Relationship of Round-bar Specimens with Isotropic Homogenous Elasto-plastic Materials by Unidirectional Tensile Test
XUE Gang
2022, 37(2): 24-36.
[Abstract](48) [PDF 17970KB](7)
Abstract:
Based on the uniaxial tensile test of round-bar specimens of isotropic homogeneous elasto-plastic material, the correlation between the deformation characteristics and the stress-strain constitutive relationship are analyzed theoretically. By the finite element method, the necessary conditions for the formation of necking and the formation process of the actual necking morphology are discussed. The results show that the material stress-strain constitutive properties and the specimen are non-ideal, and that a cylinder is a necessary condition for necking. When the equivalent plastic strain (εp) reaches a certain critical value, the flow stress (σ0) no longer increases with the increase of εp. The internal fractures formed in the later stage of necking are the reasons for the smaller curvature radius of the arc contour at the minimum cross-sectional position of the necking area.
Research on Properties of Low-viscosity Vinyl Resin for RTM
WANG Ya-ting, YANG Rui-rui, LI Xiang
2022, 37(2): 37-41.
[Abstract](100) [PDF 3846KB](15)
Abstract:
The process characteristics of vinyl resin for RTM and the mechanical properties of the resin and its composite materials are studied. The resin has a relatively low viscosity, about 240 mPa·s at 25℃. The gel time of the resin is analyzed, and the function of gel time and temperature is obtained. The apparent activation energy is relatively large, so the resin temperature should be strictly controlled in the process of molding. DSC curve is applied to analyze the curing exothermic behavior of the vinyl resin at different heating rates, and the theoretical gel temperature, curing temperature and post-curing temperature of the resin are obtained. The resin and composite materials have good mechanical properties.
Research on Polarization Curve and ESI of Ti6321 and TC4ELI
SUN Zhi-jie, LIU Qian-li, WANG Yang, JIANG Peng
2022, 37(2): 42-49.
[Abstract](251) [PDF 11891KB](15)
Abstract:
The analysis on polarization curve and electrochemical impedance spectroscopy(ESI) of Ti6321 and TC4 ELI alloy in the artificial seawater solution with PH=7 and PH=1.5 has been carried out. It is found out that the non-integrative oxide of Ti element participates in the process of anode polarization, and that the hydrogen electrochemical evolution in negative polarization process is controlled by H+ concentration and desorption, and has different Tafel slopes. Ti6321 and TC4 ELI have stable passive film in the neutral artificial seawater, while in the acid environment, the passive film on the surface of TC4 ELI isn't stable, and the polarization resistance Rp<0 appears in the impedance spectrum.
Material Application
Heat Setting and Mechanical Property Analysis of U-shaped Nickel-titanium Alloy Wire
ZOU Yi-le, GAO Chao
2022, 37(2): 50-55.
[Abstract](334) [PDF 7131KB](48)
Abstract:
Different heating conditions are applied to shape the nickel-titanium alloy wires, the mechanical properties and internal structure of the nickel-titanium alloy wires are studied, and the optimal heat setting process parameters for the nickel-titanium alloy wires are determined. The tensile properties of Ni-Ti wires are tested by tensile tester. The metallographic structure of the Ni-Ti wire is observed by optical metallographic microscope. The results show that the higher the heat setting temperature and the longer the heating time, the better the heat setting effect of the Ni-Ti wire and the closer the size of Ni-Ti wire to that of the setting die. The stresses of the top and the bottom plateaus of Ni-Ti wire decrease over the heating time, and when the temperature is 550℃ and the heating time is 20 min, the stresses of the top and the bottom plateaus are the smallest. The residual strain increases significantly when the heating time is more than 10 min. With the increase of the temperature and the heating time, the distribution of austenite structure in Ni-Ti wire is more uniform, the austenite grain boundary becomes more obvious, and the average grain size of the structure becomes larger.
Lightweight Design of Composite Evacuation Platform Based on Response Surface Method
YU Zu-xin, QIN Jun-fei, ZHANG Yong-bing, ZHUANG Yan, XU Ning, MENG Shan, CAI Bin
2022, 37(2): 56-62.
[Abstract](108) [PDF 10999KB](7)
Abstract:
In urban rail transit, evacuation platform is a necessary safety passage which can ensure the rapid and orderly evacuation of passengers from the tunnel to the safety area as soon as possible in the case of train failure or other abnormal conditions. Composite materials of light weight, high strength, strong designability and fire prevention have been gradually applied to evacuation platform. In view of the continuous improvement of the lightweight requirements for composite materials in engineering applications, the purpose of reducing the structural weight is achieved on the basis of meeting the material strength and structural deformation. In this study, the deformation and strength of the existing composite evacuation platform are analyzed, and optimization variables are defined. With its mass, strength and overall deformation as the objective function and the multi-objective optimization based on response surface method idea, the function relationship between the objective function and the optimization index is discussed. The appropriate solution is obtained by comparison, and the selected solution is further verified.Resultsshow that when the strength and the overall deformation of the optimized evacuation platform are guaranteed, its weight decreases.
Analysis on Deeping Drawing Forming of Titanium Strip Coiling from EB Titanium Ingot
TAO Hui-fa, LI Bo-bo, LIN Peng, PAN Yang-bo, LIU Yin-qi, WANG Chong-rui
2022, 37(2): 63-66,70.
[Abstract](96) [PDF 5846KB](10)
Abstract:
The deep drawing formability of titanium strip coil prepared from EB pure titanium ingot is studied by analysis on limit drawing coefficient, chemical compositions, mechanical properties and metallographic structure. The results show that drawing property of titanium strip coil prepared by EB pure titanium ingot is excellent and that the drawing temperature, oxygen content and oxygen equivalent, mechanical properties, plastic strain ratio, strain hardening index and average grain size can affect the forming performance of cold rolled titanium strip coil in the deep drawing.
Crack Defect Analysis and Elimination of Pump Casing Casting of Super Duplex Stainless Steel 5A Material
CHEN Ya-tao, WANG Ling-shui, YUAN Jin-yi, ZHENG Fei, GUO Hai-xia
2022, 37(2): 67-70.
[Abstract](52) [PDF 4222KB](11)
Abstract:
The causes of cracks in super duplex stainless steel 5 A pump casing castings are analyzed. It is found out that the structure of the casting undergoes eutectoid transformation of the ferrite phase in the slow cooling process in the mold. σ phase and secondary austenite phase precipitate from the ferrite phase, and the σ phase is the main reason for the cracking of pump casing castings. The change of contraction stress and thermal stress aggravate the cracking tendency of pump shell castings. The cracking of pump casing castings can be effectively avoided by adopting hot sand falling + hot charging furnace process or slow cooling + slow heating process.
Research of Pattern Design for Equal Polar Hole Cylinder Based on CADWIND
YAO Rong-yi, ZHANG Xiang-dong, GUAN Hong-tao
2022, 37(2): 71-74,100.
[Abstract](75) [PDF 4053KB](13)
Abstract:
The key point of winding pattern design for equal-polar cylinder is to obtain the stable winding pattern with fixed position. In this study, the effects of mandrel diameter, winding angle and friction factor on the winding pattern are studied based on CADWIND with a 140 L cylinder. The key points of pattern design for equal polar-hole cylinder are analyzed, and the method of winding pattern design proposed.
Welding Technology
Study on Interface Morphology and Properties of Zirconium/Stainless Steel Composite Plate
ZHU Lei, SHANG Zhi-xuan, CAO Lei, LIU Lin-jie
2022, 37(2): 75-79.
[Abstract](149) [PDF 7224KB](8)
Abstract:
The relationship between interface morphology and mechanical properties of double layer zirconium/stainless steel composite plate under different process parameters is studied. The ripple size and brittle phase composition of the interface are detected by metallographic inspection and energy spectrum analysis. The quality of interface is tested by mechanical property test. By comparing the interface of zirconium/stainless steel composite plate under different process conditions, the optimal composite process is determined. With the optimal process parameters, the interfacial wavelength is 1 400 μm, the wave amplitude is 230 μm and the shear strength is 260 MPa. The result can provide significant references for the domestic industrial production of zirconium/stainless steel composite plate.
Study on Performance of Aluminum/Stainless Steel Composite Connector for Cryogenic Equipment
SHANG Zhi-xuan, ZHU Lei, FAN Ke-she, CAO Lei
2022, 37(2): 80-84.
[Abstract](94) [PDF 9019KB](15)
Abstract:
The properties of aluminum/stainless steel connectors used in liquid hydrogen, liquid oxygen and liquefied natural gas storage tanks at low temperature are systematically studied, and the morphology features of the interfaces after explosive cladding analyzed. The tensile strength change under different temperature conditions are studied by the method of mechanical property test. The gas tightness before and after the welding is tested with helium leak detector, and the application reliability and the main risks of the aluminum/stainless steel connectors are analyzed.
Review
Method of Adhesives for Ship Equipment System
QIAN Jiang, FAN Ning-bo, MA Yu-liang, HU Chang-fei
2022, 37(2): 85-88.
[Abstract](1750) [PDF 3629KB](18)
Abstract:
A variety of adhesives are involved in the ship equipment system. Here are introduced the adhesives applied in different parts of the system, discussed the items that need to be assessed, and expounded the assessment methods.
Research Progress and Comprehensive Performance Evaluation of Marine Fireproof and Insulation Materials
ZHAO Jian-fei, HU Chang-fei, MA Yu-liang, LUO Wen
2022, 37(2): 89-95,100.
[Abstract](139) [PDF 5667KB](38)
Abstract:
Ship fire hazard can cause great harm, so fire insulation materials are widely used. Here are introduced the construction of standard system of marine fire insulation materials, basic performance requirements, types of action mechanism and research progress. In addition, the influence of laying quality of fire insulation materials and the performance evaluation methods are described.
Experience Exchange
Application of Structural Steel and Corrosion Prevention Technology in China
HE Ping-gen, JIANG Wen-ying, SONG Jian-ping
2022, 37(2): 96-100.
[Abstract](52) [PDF 3242KB](13)
Abstract:
As an important infrastructure, the bridge plays a key role in the national economic development. In the past few decades, on the one hand, the continuous development of the steel material and manufacturing technology has provided a strong impetus for the development of the bridge engineering in China. On the other hand, the corrosion failure of the steel structure is a significant factor influencing the stability and durability of the bridge. Therefore, it is of great importance to develop effective corrosion protection technology for steel structures. Here are summarized the research progress and engineering application of bridge structural steel in China, introduced the corrosion protection measures and application of steel structure bridge, and discussed the future development direction of bridge structural steel and corrosion prevention technology. The research result can provide references for the promoting of the research and application of bridge steel and the development of corrosion prevention technology.

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