Volume 40,Issue 6,2017 Table of Contents

1 Effect of stress aging on the microstructure and stress-rupture properties of a single crystal superalloy DD11

LIU Chenguang , ZHAO Yunsong , TANG Dingzhong , LI Chunzhi , ZHAO Zhenye

2017, 40(6):1-7. DOI: 10.11835/j.issn.1000-582X.2017.06.001

[Abstract](1014) [HTML](294) [PDF 3.42 M](913)

Abstract:
The effect of uniaxial stress aging at 1 070℃/100 MPa on the microstructural evolution and the stress rupture properties of a single crystal supperalloy DD11 was investigated.The microstructure before and after the stress aging was observed with scanning electron microscope and transmission electron microscope,and the stress rupture properties before and after the stress aging were also tested.The experiment results show that the evolution of the microstructure can be divided into two stages,rafting (first 50 h) and coarsening (after the first 50 h) of the rafting microstructure.At the first stage,the vertical direction of the γ phase channels becomes narrow or disappears gradually,and the width of horizontal direction of the γ phase channels increases gradually.At the same time,the cuboidal γ'phase expands horizontally and gradually connects with each other.At the second stage,the dimension of the rafts coarsens slightly.However,the morphology of rafting keeps stable.The stress rupture properties of 1 070℃/140 MPa decrease slightly at first stage and degrade gradually at second stage.After stress aging for 500 h,the stress rupture properties decline from initial 360 h to 140 h.The results show that the key factors for the degeneration of the stress rupture properties are the coarsening of the matrix channels and the rafting of the microstructure.

2 The effect of using limestone to displace some lime in converter on dephosphorization efficiency,gas composition and oxygen lance position

LIANG Yongchang , TANG Haiyan , LIU Wei , YANG Hongbo , GUO Senlin , WANG Guofeng , DANG Jinqian , LI Jingshe

2017, 40(6):8-14. DOI: 10.11835/j.issn.1000-582X.2017.06.002

[Abstract](960) [HTML](286) [PDF 1.84 M](1359)

Abstract:
Using limestone to displace some lime in converter can decrease the production costs of steelmaking and reduce the emission of carbon dioxide.The industrial tests and thermodynamic analysis were carried out to investigate the effect of limestone substitution ratios (18%,19%,20%,25%,28%,29%,39% and 41%) on the dephosphorization efficiency,converter gas composition and oxygen lance position.The results show that better dephosphorization efficiency can be achieved when the limestone substitution ratio is 25%,and the end point phosphorous content is 0.016%,which is reduced by 47% compared with the original process of 0.030%.Meanwhile,the moment of recovering the converter gas is one to two minutes earlier than before,and the amount of recovered gas increases.Furthermore,the more limestone is added,the earlier recovery time is.The results also show that the oxygen lance control position should be raised from 1.7 m to 1.8 m when using limestone to displace some lime in steelmaking.

3 Study on the construction method of composite finite element

YUAN Zhengqiang , XIONG Guangliang , MA Ningning

2017, 40(6):15-25. DOI: 10.11835/j.issn.1000-582X.2017.06.003

[Abstract](893) [HTML](837) [PDF 4.31 M](915)

Abstract:
In traditional finite element method,each unit is composed of a single material.While only considering the properties of a material will bring great convenience to the software programming,it also leads to a complex finite element modeling process.Therefore,in this paper,we discussed the principle of virtual work from the four nodes rectangular element and the two nodes linear element and used the energy equation to integrate the two different elements.Using VC++as the development tool,taking advantage of the parametric element characteristics and using Gaussian numerical integral method,we formed the element stiffness matrix of the common elements,according to the inverse matrix construction method of functions written plane element shape function program.Then,the element stiffness was integrated according to the node displacement number of the element,and a new type of finite elements containing plane unit and line unit was obtained.At the same time,two kinds of composite elements were applied to a simple example of calculation,in which the concentrated load was placed in the end of the cantilever beam.Through the calculation of the example,the results obtained by using the composite element method and ANSYS in the same conditions were compared.The results of the two cases are very close,the composite element construction method is correct and reliable,and at the same time,it can reduce the number of elements.

4 Corrosion behavior of Q235 steel with polysiloxane composite coating in different environment

LI Yong , LONG Yingkai , YAO Qiang , YANG Wenjing , LI Xueming , HUANG Xinyue , WANG Xiongying

2017, 40(6):26-35. DOI: 10.11835/j.issn.1000-582X.2017.06.004

[Abstract](790) [HTML](297) [PDF 6.45 M](1012)

Abstract:
Polysiloxane composite coating was coated on the surface of Q235 steel through sparying method,and the samples were corroded by atmospheric exposure test in four 220 kV transformer substations (heavy pollution area,densely populated area,general industrial area,rural settlements area) for 15 months respectively.The corrosion behavior was investigated by Tafel polarization curve and electrochemical impedance spectroscopy (EIS) test.The results show that the corrosion current density increases from 3.849 5×10^-12 A/cm² to 2.257 2×10^-10 A/cm² with the extension of time in the densely populated area.The corrosion current density decreases from 1.640 1×10^-10 A/cm² to 5.736 5×10^-11 A/cm²,and then increases to 3.929 9×10^-10 A/cm² in the densely populated area which shows the best anticorrosion ability.Combined with the self corrosion potential and coating resistance,the order of anticorrosion ability in different environment is as follow:densely populated area > rural settlements area > general industrial area > heavy pollution area.

5 Commentary on the research of bipolar high-frequency and high-voltage square wave pulse power supply

WEI Xinlao , GUO Zhengliang , WANG Haoran

2017, 40(6):36-46. DOI: 10.11835/j.issn.1000-582X.2017.06.005

[Abstract](1151) [HTML](879) [PDF 2.79 M](3341)

Abstract:
The development and applications of bipolar high-frequency and high-voltage square wave pulse power supply were generalized in this paper,for promoting its studies and improvement.With the summary and commentary of several main technical schemes based on the solid-state power electronic switching devices,we briefly introduced the related technologies to improve the performance of the pulse power supply.In regard to existing technical solutions,we expatiated on the problems of implementation and prospect of further development trend.

6 Design of an improved static var compensation system

JIANG Jianguo , WANG Mengqian

2017, 40(6):47-53. DOI: 10.11835/j.issn.1000-582X.2017.06.006

[Abstract](774) [HTML](744) [PDF 4.37 M](896)

Abstract:
In this paper,based on the principle of static var generator,the positive and negative components of phase are first phase locked respectively combined with symmetrical component method in the d-q coordinate system,and then the active current and reactive value of load current in the positive and negative sequence are calculated.So we can avoid the phase-locked angle error caused by asymmetrical three-phase voltages through traditional phase locked loop technology.Then the DC signal is extracted using integral filtering method instead of the traditional low-pass filter.When the system of three-phase is asymmetry,each current of phase is simplified then processed by integral filter,which reduces the inherent delay in the traditional system.Finally,an improved reactive power compensation system simulation model is set up in the MATLAB environment.From a series of simulations of fundamental current extraction and reactive power compensation,we can see that the improved SVG can realize the real-time detection of reactive current:the system detection delay is less than 0.02 s and reduced by 60% compared with the traditional detection model.The power factor of the original system can be increased to more than 95% after adding the static var compensation system in a power cycle.

7 Design of constant resistance giving way and anti-impact device of mining column and its characteristic analysis

TANG Zhi , PAN Yishan , ZHU Xiaojing , CUI Naixin

2017, 40(6):54-59. DOI: 10.11835/j.issn.1000-582X.2017.06.007

[Abstract](735) [HTML](333) [PDF 2.10 M](1153)

Abstract:
In order to improve the anti-impact mechanical properties of column,a kind of constant resistance giving way and anti-impact device of mining column is designed.The device is composed of a joint,clamp,energy absorption component cover,energy absorption component and pin.According to the Chinese standard of column,the bearing capacity of anti-impact device is determined,and the working and anti-impact principle of the device is given out.The contrastive analysis is conducted to study the deformation and stress of conventional column and the column installing anti-impact device under impact loading.The results show that under the same impact loading,the deformation of anti-impact column is far less than that of conventional column.The energy absorption and anti-impact component can effectively reduce the impact force on column in the deformation stage.The anti-impact device can greatly enhance the anti-impact properties of column,and it can be easily installed on the existing conventional column.And the constant resistance giving way and anti-impact device can be used in the automotive,aerospace industry,highway safety protection and other fields.

8 Simulation analysis of vibration response for coupled plate-beam

ZHANG Lihua , LI Yi , XIA Xiaojun , XU Zhongming

2017, 40(6):60-66. DOI: 10.11835/j.issn.1000-582X.2017.06.008

[Abstract](834) [HTML](827) [PDF 3.27 M](1080)

Abstract:
Coupled plate-beam structure is a typical structure whose vibration performance is in mid-frequency.Aiming at the shortcomings of the existing deterministic numerical methods in the prediction of the mid-frequency,we proposed a method to predict the vibration response of coupled plate-beam structure on the basis of wave-based method (WBM).First,based on the vibration response of Kirchhoff plate and Euler-Bernoulli beam,the system matrix of coupled plate-beam structure was deduced by using the weighted residual method using the transversal displacement and the torsional angle between plate and beam as the coupling variable.Then the wave-based mathematical model for coupled plate-beam structure was established.Finally,the coupled structure of rectangular plates with four sides clamped and a slender beam was taken as an example to validate the proposed method.The contour of the coupled structure at100 Hz and its frequency response from 50-500 Hz show that compared with finite element method (FEM),the wave-based model for coupled plate-beam structure is more efficient in higher frequency range and has higher convergence.At the same computational accuracy,its computational cost (degree of freedom of model and computational time) decreases significantly.

9 TTR warning and anti-rollover control for semi-trailer

OU Jian , WANG Yongsheng , YANG Echuan , FU Lijuan , LIU Guangming

2017, 40(6):67-76. DOI: 10.11835/j.issn.1000-582X.2017.06.009

[Abstract](1056) [HTML](489) [PDF 3.18 M](1114)

Abstract:
In order to warn drivers of rollover threat states of semi-trailer and control the states in time,the current motion states of semi-trailer were estimated in real time by using Kalman filtering technique.Meanwhile,we treated semi-trailer in TruckSim as a real vehicle and took the process noise and measurement noise into consideration.Then a TTR (time-to rollover) rollover warning algorithm associated with model prediction was established by determining vehicle lateral load transfer rate as the rollover threat index.In addition,through combining with optimal control algorithm,anti-rollover control strategy was developed based on TTR rollover warning algorithm.Simulations show the proposed control strategy can warn drivers effectively of the dangerous situation,and control rollover threat states of semi-trailer to prevent rollover.

10 Research on the semantic model of processing resources in cloud manufacturing

WANG Weixing

2017, 40(6):77-85. DOI: 10.11835/j.issn.1000-582X.2017.06.010

[Abstract](675) [HTML](304) [PDF 3.03 M](1071)

Abstract:
To solve the problem of virtualized encapsulation of processing equipment resources in cloud manufacturing,an open and flexible processing equipment resource model was established.On the basis of analyzing the connotation,classification and characteristics of manufacturing resources,the characteristics of processing equipment resources were analyzed first.Then combined with semantic knowledge and WEB technology,the resource model of processing equipment was established.The semantic description method of processing equipment resources was given,and the semantic description template was established.Finally,the cloud manufacturing resource matching process was described in detail.The research would provide an important basis and condition for resource management of cloud manufacturing platform.

11 Catalytic synthesis of isoamyl acetate by amino acid functional heteropolyacid as catalysts and its kinetics

LIANG Juanjuan , ZHAO Yuqian , LI Fanghao , HAN Xiaoxiang , FANG Miaoli

2017, 40(6):86-94. DOI: 10.11835/j.issn.1000-582X.2017.06.011

[Abstract](1073) [HTML](288) [PDF 2.81 M](1096)

Abstract:
The organic-inorganic hybrid catalyst,namely[GlyH]_xH_3-xPW₁₂O₄₀(x=1.0-3.0),was prepared by combining phosphotungstic acid and glycine (Gly).The effects of various factors on the catalytic synthesis of isoamyl acetate with using[GlyH]_xH_3-xPW₁₂O₄₀(x=1.0-3.0) as catalysts were studied,and the synthesis process of isoamyl acetate was optimized by response surface methodology (RSM).The results show that[GlyH]_1.0-H_2.0PW₁₂O₄₀ catalyst has the highest catalytic esterification reactivity and reusability.The optimum conditions are n(isoamylol):n(acetic acid)=1.05:1,the amount of catalyst to acetic acid 4.5%,reaction time 2.0 h and water-carrying agent 10 mL.Under these conditions,the yield of isoamyl acetate reaches 98.5%,which is in basic agreement with values predicted by the mathematical model.Under the optimal conditions,the active energy of the esterification is 79.73 kJ/mol.

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