In local post weld heat treatment, the temperature difference is the criterion of the process. The temperature field in the main stream pipe under local post weld heat treatment is simulated by finite element method. ...In local post weld heat treatment, the temperature difference is the criterion of the process. The temperature field in the main stream pipe under local post weld heat treatment is simulated by finite element method. A close-loop control program is designed to simulate the temperature field of two different pipes. Both the skin effect of induction heating and electro-thermal coupled effect are considered in the heating model. The local heat treatment temperature difference at the inner and outer side of the pipe is analyzed and the different convection conditions are also considered. The simulation results show that in appropriate induction heating process, the temperature difference in the pipe can be controlled within 30 ℃.展开更多
In this paper, the Kirchhoffs transformation is popularized to the nonlinear heat conduction problem which the heat conductivity can be expressd as a multinomial of temperature firstly, the boundary condition of heat ...In this paper, the Kirchhoffs transformation is popularized to the nonlinear heat conduction problem which the heat conductivity can be expressd as a multinomial of temperature firstly, the boundary condition of heat conduction problem is determined by analytics.Secondly, the incubation peroid superposition and the linear combination law is employed to simulate the transient phasses transformation in the process of heat treatment of materials. That the begin time of phase transformation, the type of phase transformation and the amount of phase constitution is determined simply.Finally, the three-dimension Dual Reciprocity Boundary Element Method is usedto analysis the total process of various heat treatment of component, the results of numerical calculation of examples show that the method provided in this paper is effectivce.展开更多
In this paper, mathematical models and FEA formulation for implementing heat treatment process simulation were given out. The various coupling effects were treated. The object-oriented methodology of developing heat t...In this paper, mathematical models and FEA formulation for implementing heat treatment process simulation were given out. The various coupling effects were treated. The object-oriented methodology of developing heat treatment simulation was explored. The framework of simulating programs was outlined. The main C++ classes were developed, some important member functions were implemented. The present research work shows that using object-oriented method can greatly reduce the amount of coding. The programs are clear in conception, easy to test, modify and expand. By using the methodology introduced in this paper, one heat treatment process three dimensional simulation tool was developed.展开更多
In the present work,Ce_(17)Fe_(76.5)Co_1Zr_(0.5)B_6 ribbons were prepared by a direct melt spinning method.The effects of chamber pressure and magnetic field annealing temperature on the magnetic properties and micros...In the present work,Ce_(17)Fe_(76.5)Co_1Zr_(0.5)B_6 ribbons were prepared by a direct melt spinning method.The effects of chamber pressure and magnetic field annealing temperature on the magnetic properties and microstructures of the alloys were investigated.The grain size and content of Ce_(2)Fe_(14)B phase can be changed by adjusting the chamber pressure,and the optimal magnetic performance is obtained at0.04 MPa.The magnetic properties can be influenced under magnetic field heat treatment.When the annealing temperature is lower than the Curie temperature,the refinement and a uniform distribution of the grains is obtained.The irreversible magnetic susceptibility curve reveals that magnetic field heat treatment enhances the exchange coupling interaction between grains of the Ce_(2)Fe_(14)B phase.When the magnetic field annealing temperature is 438 K,the alloy displays the optimal magnetic properties.Compared with the as-spun sample,the values of intrinsic coercivity(H_(ci)),remanence(B_r) and maximum energy product((BH)max) increase by 3.4%,9.8% and 18.7%,respectively.This work provides an effective approach by which to enhance the magnetic properties of Ce-Fe-B alloys.展开更多
Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process an...Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process and the transformation of retained austenite for the steel were accelerated by the pulse magnetic field,and the tempering period could be reduced to half of the original.It was shown by the analyses of X-ray and eletron microscopy that the precipitation of carbides becomes more homogeneous and dispersive,and the tetragonality of martensite increases obviousely,which causes the improvement of hardness and red-hardness for the steel.It was confirmed that the service life of tools as centre bits,screw taps and punches for nuts could be increased by 0.4 to 1.4 times by the tempering in magnetic field.展开更多
The heat treatment microstructures and XRD patterns of the Mg-8Gd-5Y-2Zn-0.5Zr(wt.%) alloy in the absence and presence of a 10T high magnetic field have been investigated.The investigations show that the grains of α-...The heat treatment microstructures and XRD patterns of the Mg-8Gd-5Y-2Zn-0.5Zr(wt.%) alloy in the absence and presence of a 10T high magnetic field have been investigated.The investigations show that the grains of α-Mg demonstrate a preferred orientation due to the magnetic driving force.In addition,high magnetic fields can promote the growth of the long period ordered structure(LPS) phase to the grain interior.And the corresponding mechanisms are also discussed in this article.展开更多
TbFe_2,as a typical magnetostrictive material,is ferrimagnetic.Its magnetostrictive property can be improved by an external magnetic field at a temperature below its Curie temperature.In this paper,the effects of high...TbFe_2,as a typical magnetostrictive material,is ferrimagnetic.Its magnetostrictive property can be improved by an external magnetic field at a temperature below its Curie temperature.In this paper,the effects of high magnetic fields on the preferred orientation,phase composition and magnetostrictive property of Tb-Fe alloys during heat treatment process were investigated.It was found that the magnetostriction performance of the alloy annealed in an 11.5 T magnetic field was improved by 30%contrary to that without magnetic field.Such increase can be attributed to the increase in orientation degree of <113> caused by the high magnetic field during the heat treatment.展开更多
文摘In local post weld heat treatment, the temperature difference is the criterion of the process. The temperature field in the main stream pipe under local post weld heat treatment is simulated by finite element method. A close-loop control program is designed to simulate the temperature field of two different pipes. Both the skin effect of induction heating and electro-thermal coupled effect are considered in the heating model. The local heat treatment temperature difference at the inner and outer side of the pipe is analyzed and the different convection conditions are also considered. The simulation results show that in appropriate induction heating process, the temperature difference in the pipe can be controlled within 30 ℃.
文摘In this paper, the Kirchhoffs transformation is popularized to the nonlinear heat conduction problem which the heat conductivity can be expressd as a multinomial of temperature firstly, the boundary condition of heat conduction problem is determined by analytics.Secondly, the incubation peroid superposition and the linear combination law is employed to simulate the transient phasses transformation in the process of heat treatment of materials. That the begin time of phase transformation, the type of phase transformation and the amount of phase constitution is determined simply.Finally, the three-dimension Dual Reciprocity Boundary Element Method is usedto analysis the total process of various heat treatment of component, the results of numerical calculation of examples show that the method provided in this paper is effectivce.
文摘In this paper, mathematical models and FEA formulation for implementing heat treatment process simulation were given out. The various coupling effects were treated. The object-oriented methodology of developing heat treatment simulation was explored. The framework of simulating programs was outlined. The main C++ classes were developed, some important member functions were implemented. The present research work shows that using object-oriented method can greatly reduce the amount of coding. The programs are clear in conception, easy to test, modify and expand. By using the methodology introduced in this paper, one heat treatment process three dimensional simulation tool was developed.
基金supported by the National Natural Science Foundation of China (51971125)。
文摘In the present work,Ce_(17)Fe_(76.5)Co_1Zr_(0.5)B_6 ribbons were prepared by a direct melt spinning method.The effects of chamber pressure and magnetic field annealing temperature on the magnetic properties and microstructures of the alloys were investigated.The grain size and content of Ce_(2)Fe_(14)B phase can be changed by adjusting the chamber pressure,and the optimal magnetic performance is obtained at0.04 MPa.The magnetic properties can be influenced under magnetic field heat treatment.When the annealing temperature is lower than the Curie temperature,the refinement and a uniform distribution of the grains is obtained.The irreversible magnetic susceptibility curve reveals that magnetic field heat treatment enhances the exchange coupling interaction between grains of the Ce_(2)Fe_(14)B phase.When the magnetic field annealing temperature is 438 K,the alloy displays the optimal magnetic properties.Compared with the as-spun sample,the values of intrinsic coercivity(H_(ci)),remanence(B_r) and maximum energy product((BH)max) increase by 3.4%,9.8% and 18.7%,respectively.This work provides an effective approach by which to enhance the magnetic properties of Ce-Fe-B alloys.
文摘Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process and the transformation of retained austenite for the steel were accelerated by the pulse magnetic field,and the tempering period could be reduced to half of the original.It was shown by the analyses of X-ray and eletron microscopy that the precipitation of carbides becomes more homogeneous and dispersive,and the tetragonality of martensite increases obviousely,which causes the improvement of hardness and red-hardness for the steel.It was confirmed that the service life of tools as centre bits,screw taps and punches for nuts could be increased by 0.4 to 1.4 times by the tempering in magnetic field.
基金Item Sponsored by the Fundamental Research Funds for the Central University[NO.DUT12JN02]
文摘The heat treatment microstructures and XRD patterns of the Mg-8Gd-5Y-2Zn-0.5Zr(wt.%) alloy in the absence and presence of a 10T high magnetic field have been investigated.The investigations show that the grains of α-Mg demonstrate a preferred orientation due to the magnetic driving force.In addition,high magnetic fields can promote the growth of the long period ordered structure(LPS) phase to the grain interior.And the corresponding mechanisms are also discussed in this article.
基金Item Sponsored by the National Natural Science Foundation of China(Grant Nos.51006020and51174056)the Fundamental Research Funds for the Central Universities(Grant Nos.N090109001,N100409008,and N100609001)+1 种基金the National Basic Research Program of China(Grant No.2011CB612206)the Wuhan National High Magnetic Field Center(Grant No.WHMFCK2011006)
文摘TbFe_2,as a typical magnetostrictive material,is ferrimagnetic.Its magnetostrictive property can be improved by an external magnetic field at a temperature below its Curie temperature.In this paper,the effects of high magnetic fields on the preferred orientation,phase composition and magnetostrictive property of Tb-Fe alloys during heat treatment process were investigated.It was found that the magnetostriction performance of the alloy annealed in an 11.5 T magnetic field was improved by 30%contrary to that without magnetic field.Such increase can be attributed to the increase in orientation degree of <113> caused by the high magnetic field during the heat treatment.
