A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of me...A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of median filter is used to estimate the weld background. After the weld background is subtracted from the original image, an adaptite threshold segmentation algorithm is proposed to obtain the binary image, and then the morphological close and open operation, labeling algorithm and fids＇e alarm eliminating algorithm are applied to pracess the binary image to obtain the defect, ct detection result. At last, a fast realization procedure jbr proposed method is developed. The proposed method is tested in real-time X-ray image,s obtairted in different X-ray imaging sutems. Experiment results show that the proposed method is effective to detect low contrast weld dejects with few .false alarms and is adaptive to various types of real-time X-ray imaging systems.展开更多
Electroslag remelting (ESR) process using consumable electrode deoxidized with Ca-Si and Fe-Si instead of Al, and acid slag (CaF_2SiO_2Al_2O_3CaO) instead of universal slag ANF_6(CaF_2. 70 %+A1_2O_3.30 %) could change...Electroslag remelting (ESR) process using consumable electrode deoxidized with Ca-Si and Fe-Si instead of Al, and acid slag (CaF_2SiO_2Al_2O_3CaO) instead of universal slag ANF_6(CaF_2. 70 %+A1_2O_3.30 %) could change brittle inclusion (alumina) to ductile inclusion (silicate) in remelted steel. Fatigue life of bearing steel could be increased significantly in this way.展开更多
The partially stabilized ZrO2 (PSZ) particles were introduced into TiB2 ceramics to improve its density and mechanical properties. The results show that the addition of PSZ is very effective not only in bettering the ...The partially stabilized ZrO2 (PSZ) particles were introduced into TiB2 ceramics to improve its density and mechanical properties. The results show that the addition of PSZ is very effective not only in bettering the sinterability but also in enhancing the flexural strength and fracture toughness of TiB2.展开更多
The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms...The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms of the inner railway radius, wheelbase, gauge, girder length of the doable railway suspended vehicle for automatic transportation in the welding product line. The mutual-restriction among the design variables is discussed and the selective ranges of the variables are confirmed. The result shows that the stability of the doable railway suspended vehicle for automatic transportation in the welding product line depends on parameters of the inner railway radius, wheelbase, gauge, girder length. The optimal results of the optimal objective and design variables have research significance for the virtual prototype of the doable suspension railway automation vehicle. The optimal results are input into the simulation model iteratively and the simulation results are fed back to the physical prototype. The veracity and reliability of peoformance forecast are improved so that the manufacture cost of the doable suspension railway automation vehicle is reduced significantly.展开更多
Interaction rule between representative RE and Sn, Sb, Pb, Cu, S, P low melting point elements respectively in Fe , Cu , Al , Ni base liquid solutions including totally 34 ternary and quarternary systems was inve...Interaction rule between representative RE and Sn, Sb, Pb, Cu, S, P low melting point elements respectively in Fe , Cu , Al , Ni base liquid solutions including totally 34 ternary and quarternary systems was investigated. For each system some thermodynamic properties were obtained, such as the standard free energies of equilibrium reactions, activity interaction coefficients etc ..展开更多
The influence of the metal pool depth and the local solidification time on the structure of high speed steel ingot produced by electroslag remelting (ESR) process has been studied by measuring the dendritic arm spacin...The influence of the metal pool depth and the local solidification time on the structure of high speed steel ingot produced by electroslag remelting (ESR) process has been studied by measuring the dendritic arm spacing and the size of the carbides. It is shown that the metal pool depth is a factor that influences the uniformity of the ESR ingot structure and not only the dendritic arm spacing, but also the size of the carbides can be influenced by the local solidification time in the solidification process of the ingot. The relationship between the melting rate during ESR process and the local solidification time has been studied. It is shown that there is an optimum melting rate at which the local solidification time is minimum as a result of the combination of the influence of the melt rate on the width of the local mushy zone and on the local solidification rate. The influence of the inoculants on the solidification structure of high speed steel produced by ESR has been studied and it is shown that the size of the grain can be significantly reduced by inoculation process.展开更多
This paper first briefly introduces the history of the development of China valve steel from mainly adopting valve steel from the former Soviet Uinoin in the fifties, manufacturing by herself in the sixties, to introd...This paper first briefly introduces the history of the development of China valve steel from mainly adopting valve steel from the former Soviet Uinoin in the fifties, manufacturing by herself in the sixties, to introducing advanced valve steel from other countries and instituting Chinese valve steel system since the seventies.The demand of valve steel for China internal combustion engine including material specification and quantity required at present is discussed. The principal difficulties being faced with in the development of China valve steel at the moment are put forward. Finally, a detailed discussion is made on the development of China valve steel with suggstions of developing 5Cr8Si2 and MF811 martensitic steels, 21 2N austenitic steel used for gasoline engine, 23 8N austenitic steel used for diesel engine, 21 4NWNb high strength austenitic steel and LF2 and LF4 for valve alloy.[WT5”BZ〗展开更多
A study has been carried out on the effect of continuous cooling with different rate from 1 200 ℃ on the brittleness of vacuum melted,extra-low interstitial Cr18Mo2 ferritic stainless steels.The ductile-brittle trans...A study has been carried out on the effect of continuous cooling with different rate from 1 200 ℃ on the brittleness of vacuum melted,extra-low interstitial Cr18Mo2 ferritic stainless steels.The ductile-brittle transition temperature was found to be the lowest after water cooling and the highest after furnace cooling.The increase of brittleness with cooling rate decrease is attributed to the formation of more nitrides.With the increase of titanium content the ductile- brittle transition temperature increases significantly.A low transition temperature occurred in steel containing0.18%Nb,and further increase of niobium brought about an increase of transition temperature.The transition temperature of ferritic stainless steel was raised severely by the precipitation of nitrides(Cr2N,Cr2Nb2N2and TiN)and oxides(Al2O3)promoting brittle crack initiation.展开更多
According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill t...According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill train.On the basis of improving width range of continuous casting of slab,we obtained a good result of greatly increasing the yield of slab→coil is achieved.展开更多
The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration ...The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration of gold and silver ore deposits in recent years. The minerogenic series of the Daiyunshan-Shiniushan volcanic depression is discussed in this paper based on the analysis of major metallogenic types and factors. According to the study of enormous ore deposits and occurrences in the study area, two minerogenic series have been recognized: 1. Late Jurassic Au-Ag-Pb-Zn minerogenic series related to intermediate-acid, acid volcanic formations; 2. nonmetallic minerogenic series (pyrophyllite, alunite pearlite, andalusite, zeolite, corundum and so on) related to intermediate and acid volcanic formations. The division and study of the minerogenic series have revealed metallogenic and time-space distribution characteristics of the ore deposits in the volcanic belt of the southeast coastal area in China, which are of economic importance for metallogenic prognosis.展开更多
Phase analysis of titanium in steel has been carried out on thirty samples with different Ticontent from 0. 036 %-0. 204% . The various heat treatments for the samples are to anneal at 1050-1200 ℃ for a while ,follo...Phase analysis of titanium in steel has been carried out on thirty samples with different Ticontent from 0. 036 %-0. 204% . The various heat treatments for the samples are to anneal at 1050-1200 ℃ for a while ,followed by cooling at a rate of 1 . 10, 20 ℃/s ,respectively.It is achieved to separate and determine fine particle TiC ,coarse particle Ti_2CS and TiN ex-tracted from steel by controlling the oxidation potential and acidity of solutions.The results of quantrtative analysis of the individual phase show that 0. 09 %- 0. 13 % Ti-contentis enough to eliminate free nitrogen and transform MnS into Yi_2CS in steel effectively. In the case of0. 06 %- 0. 10 % Ti-content combined with annealing at 1050℃. and quick cooling at 20 ℃/s ,a prop-er amount of fine particle TiC can be precipitated and the rate of TiC (fine )/TiC (total )is high ,which arebeneficial to increase strength and toughness of steel. More Ti-content or cooling slowly will preciprtatemore coarse particle TiC which decreaces toughness severely. The proposed methods for quantitativephase analysis of titanium in steel are given in detail.展开更多
The measured results show that the overexpanded supersonic jet velocity produced by low stagnation pressure (0.53 MPa) attenuates quickly, deviates greatly with smaller impact area and large energy loss. According to ...The measured results show that the overexpanded supersonic jet velocity produced by low stagnation pressure (0.53 MPa) attenuates quickly, deviates greatly with smaller impact area and large energy loss. According to the measured results and the analysis of lashing energy of jet on the bath, the technological parameters of nitrogen flow in slag splashing were proposed.展开更多
Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃...Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃. The transpassive dissolution potential of the alloy matrix under above conditions is about 1 140 mV (SCE), at which GCP phase is in passive state and can be isolated from the alloy.[WT5”HZ〗展开更多
The application of the hot-rolled micronlloyed medium-carbon steel is limited due to its lower toughness compared with quenched and tempered steels.A high strength microalloyed medium-carbon steel has been developed t...The application of the hot-rolled micronlloyed medium-carbon steel is limited due to its lower toughness compared with quenched and tempered steels.A high strength microalloyed medium-carbon steel has been developed to meet the increasing demand for eliminating heat treatment.The effects of chemical compositions,hot-deforming temperatures and cooling rates after hot-deforming on mechanical properties of the steel were investigated.Attention was given to the steel toughness above the required value for safety components in application.The basic microstructural variables controlling the properties were discussed.It is demonstrated that toughness and machinability can be improved through the addition of 0.5%Si,0.5%S and 0.01%Ti.Toughness can be further improved by controlling hot-deforming temperature and subsequent cooling rate.展开更多
Thermodynamics of Cu-Ce-O,Cu-Ce-S and Cu-Ce-0-S solutions at 1200℃ were studied by using solid electrolyte cell and chemical equilibrium method.The equilibrium constant of deoxidation,desulfurization and deoxysulfuri...Thermodynamics of Cu-Ce-O,Cu-Ce-S and Cu-Ce-0-S solutions at 1200℃ were studied by using solid electrolyte cell and chemical equilibrium method.The equilibrium constant of deoxidation,desulfurization and deoxysulfurization by Ce,the Gibbs standard reaction free energies of the formation of Ce_2O_3,CeS and Ce_2O_2S in Cu-base solution,activity interaction coefficients of S and Ce,temperature dependence of standard reaction free energy of solution of Ce in Cu,self-interaction coefficients of Ce in liquid Cu have been obtained.The phase precipitation diagram for Cu-CeS-O system has been plotted.The thermodynamic condition of the existence of Ce_2O_3,CeS and Ce_2O_2S in liquid Cu has been determined.It provides the basis for predicting the sequence and the type of equilibrium inclusions of Ce formed in Cu-base solution.展开更多
With specially designed hot rolling test equipment,the surface deterioration process of hot rolling mill rolls can be simulated and representative samples were obtained.Thus a series of micro-analyses can be done onto...With specially designed hot rolling test equipment,the surface deterioration process of hot rolling mill rolls can be simulated and representative samples were obtained.Thus a series of micro-analyses can be done onto the sample's worn surface,including wear loss,worn surface morphology,wear mode,oxidation and other influences from environment conditions.A leading study has been done with a high chromium cast iron to show the rolling test conditions and the methodologies of follow-up investigations for all the above-mentioned micro-analyses.Primary results have shown that high chromium iron roll may undergo complex degrading mechanism,and most of them can be investigated with the help of this research method-展开更多
By technological experiments on bottom pulverized coal injection in a 10 t converter,the metallurgical reaction of continuous coal-oxygen injected into molten steel was studied.An assumption of direct burning of coal ...By technological experiments on bottom pulverized coal injection in a 10 t converter,the metallurgical reaction of continuous coal-oxygen injected into molten steel was studied.An assumption of direct burning of coal in molten steel is proposed and the result that low carbon steel can also be produced with coal injection is explained.The formulae for decarburization of melting bath were given.The apparent desulphurization rate constant is measured and activation energy of dephosphorization calculated.The influence of coal injection on nitrogen pick-up is studied too.展开更多
By using a reformed laboratory rolling mill,hot wear test under near service conditions has been carried out to examine the wear mechanisms of high chromium iron roll.Each time after being rolled up to a given cycle,t...By using a reformed laboratory rolling mill,hot wear test under near service conditions has been carried out to examine the wear mechanisms of high chromium iron roll.Each time after being rolled up to a given cycle,the worn morphology of roll surface was examined under SEM and occasionally by AES.Based on rolling conditions and lasting of in-service time,various wear characteristics have been identified distinctly.It involves abrasive wear and oxidation wear for matrix phase,fatigue wear,polishing wear and grain pull-out wear for carbides,smear adhesive wear,chemical wear,and in extreme case,plasticity-dominated wear.At the same time,wear type is also discussed compatibly in terms of abrasive wear,fatigue wear,as well as chemical wear according to conventional classification.And only in an extreme situation,i.e.rolling without cooling water,adhesive wear may partially be involved.At anytime under specified conditions,there are always several wear mechanisms occurring simultaneously,but usually only one of them can be identified as the dominant mode.And finally a wear mechanism figure can be depicted to qualitatively describe the relationship among them.展开更多
The metallurgical properties of cold bound pellet were tested and analysed, and the behaviour and characters of reduction in the shaft were further investigated on the basis of analysis. The experimental results indic...The metallurgical properties of cold bound pellet were tested and analysed, and the behaviour and characters of reduction in the shaft were further investigated on the basis of analysis. The experimental results indicated that the metallurgical properties of cold bound pellet could satisfy the demands of the shaft direct reduction. The reduction of ferrous oxide with gas was taken as the domination. The reduction ratio of ferrous oxide with fixed carbon increased with the raising of temperature, and most part of the carbon remained in metallized pellet. The shaft could be smoothly operated to obtain rather higher constant utilization.展开更多
Corrosion behavior of four oxide dispersion strengthened(ODS) ferritic alloys exposed in thermal convective liquid sodium loop for 4 000 h was examined.Surface observation results reveal that coral-like surfaces with ...Corrosion behavior of four oxide dispersion strengthened(ODS) ferritic alloys exposed in thermal convective liquid sodium loop for 4 000 h was examined.Surface observation results reveal that coral-like surfaces with deposit initially formed on surfaces of all exposed specimens.In tested alloy S2,χ-phase precipitated in specimen center,and a depleted χ- phase zone formed near the specimen surface.There is a transition area between the surface and center.In the other tested alloys,no notable change on microstructure was observed.Grain boundary attack was not found in any of the tested specimens.Tensile test results indicate that sodium corrosion of the four ODS ferritic alloys for 3 000 h had no notable effect on their tensile properties.展开更多
文摘A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of median filter is used to estimate the weld background. After the weld background is subtracted from the original image, an adaptite threshold segmentation algorithm is proposed to obtain the binary image, and then the morphological close and open operation, labeling algorithm and fids＇e alarm eliminating algorithm are applied to pracess the binary image to obtain the defect, ct detection result. At last, a fast realization procedure jbr proposed method is developed. The proposed method is tested in real-time X-ray image,s obtairted in different X-ray imaging sutems. Experiment results show that the proposed method is effective to detect low contrast weld dejects with few .false alarms and is adaptive to various types of real-time X-ray imaging systems.
文摘Electroslag remelting (ESR) process using consumable electrode deoxidized with Ca-Si and Fe-Si instead of Al, and acid slag (CaF_2SiO_2Al_2O_3CaO) instead of universal slag ANF_6(CaF_2. 70 %+A1_2O_3.30 %) could change brittle inclusion (alumina) to ductile inclusion (silicate) in remelted steel. Fatigue life of bearing steel could be increased significantly in this way.
文摘The partially stabilized ZrO2 (PSZ) particles were introduced into TiB2 ceramics to improve its density and mechanical properties. The results show that the addition of PSZ is very effective not only in bettering the sinterability but also in enhancing the flexural strength and fracture toughness of TiB2.
基金Supported by Country Innovative Fund Project(05C26112200399)
文摘The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms of the inner railway radius, wheelbase, gauge, girder length of the doable railway suspended vehicle for automatic transportation in the welding product line. The mutual-restriction among the design variables is discussed and the selective ranges of the variables are confirmed. The result shows that the stability of the doable railway suspended vehicle for automatic transportation in the welding product line depends on parameters of the inner railway radius, wheelbase, gauge, girder length. The optimal results of the optimal objective and design variables have research significance for the virtual prototype of the doable suspension railway automation vehicle. The optimal results are input into the simulation model iteratively and the simulation results are fed back to the physical prototype. The veracity and reliability of peoformance forecast are improved so that the manufacture cost of the doable suspension railway automation vehicle is reduced significantly.
基金Project Sponsored by the National Natural Science Foundation
文摘Interaction rule between representative RE and Sn, Sb, Pb, Cu, S, P low melting point elements respectively in Fe , Cu , Al , Ni base liquid solutions including totally 34 ternary and quarternary systems was investigated. For each system some thermodynamic properties were obtained, such as the standard free energies of equilibrium reactions, activity interaction coefficients etc ..
文摘The influence of the metal pool depth and the local solidification time on the structure of high speed steel ingot produced by electroslag remelting (ESR) process has been studied by measuring the dendritic arm spacing and the size of the carbides. It is shown that the metal pool depth is a factor that influences the uniformity of the ESR ingot structure and not only the dendritic arm spacing, but also the size of the carbides can be influenced by the local solidification time in the solidification process of the ingot. The relationship between the melting rate during ESR process and the local solidification time has been studied. It is shown that there is an optimum melting rate at which the local solidification time is minimum as a result of the combination of the influence of the melt rate on the width of the local mushy zone and on the local solidification rate. The influence of the inoculants on the solidification structure of high speed steel produced by ESR has been studied and it is shown that the size of the grain can be significantly reduced by inoculation process.
文摘This paper first briefly introduces the history of the development of China valve steel from mainly adopting valve steel from the former Soviet Uinoin in the fifties, manufacturing by herself in the sixties, to introducing advanced valve steel from other countries and instituting Chinese valve steel system since the seventies.The demand of valve steel for China internal combustion engine including material specification and quantity required at present is discussed. The principal difficulties being faced with in the development of China valve steel at the moment are put forward. Finally, a detailed discussion is made on the development of China valve steel with suggstions of developing 5Cr8Si2 and MF811 martensitic steels, 21 2N austenitic steel used for gasoline engine, 23 8N austenitic steel used for diesel engine, 21 4NWNb high strength austenitic steel and LF2 and LF4 for valve alloy.[WT5”BZ〗
文摘A study has been carried out on the effect of continuous cooling with different rate from 1 200 ℃ on the brittleness of vacuum melted,extra-low interstitial Cr18Mo2 ferritic stainless steels.The ductile-brittle transition temperature was found to be the lowest after water cooling and the highest after furnace cooling.The increase of brittleness with cooling rate decrease is attributed to the formation of more nitrides.With the increase of titanium content the ductile- brittle transition temperature increases significantly.A low transition temperature occurred in steel containing0.18%Nb,and further increase of niobium brought about an increase of transition temperature.The transition temperature of ferritic stainless steel was raised severely by the precipitation of nitrides(Cr2N,Cr2Nb2N2and TiN)and oxides(Al2O3)promoting brittle crack initiation.
文摘According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill train.On the basis of improving width range of continuous casting of slab,we obtained a good result of greatly increasing the yield of slab→coil is achieved.
文摘The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration of gold and silver ore deposits in recent years. The minerogenic series of the Daiyunshan-Shiniushan volcanic depression is discussed in this paper based on the analysis of major metallogenic types and factors. According to the study of enormous ore deposits and occurrences in the study area, two minerogenic series have been recognized: 1. Late Jurassic Au-Ag-Pb-Zn minerogenic series related to intermediate-acid, acid volcanic formations; 2. nonmetallic minerogenic series (pyrophyllite, alunite pearlite, andalusite, zeolite, corundum and so on) related to intermediate and acid volcanic formations. The division and study of the minerogenic series have revealed metallogenic and time-space distribution characteristics of the ore deposits in the volcanic belt of the southeast coastal area in China, which are of economic importance for metallogenic prognosis.
文摘Phase analysis of titanium in steel has been carried out on thirty samples with different Ticontent from 0. 036 %-0. 204% . The various heat treatments for the samples are to anneal at 1050-1200 ℃ for a while ,followed by cooling at a rate of 1 . 10, 20 ℃/s ,respectively.It is achieved to separate and determine fine particle TiC ,coarse particle Ti_2CS and TiN ex-tracted from steel by controlling the oxidation potential and acidity of solutions.The results of quantrtative analysis of the individual phase show that 0. 09 %- 0. 13 % Ti-contentis enough to eliminate free nitrogen and transform MnS into Yi_2CS in steel effectively. In the case of0. 06 %- 0. 10 % Ti-content combined with annealing at 1050℃. and quick cooling at 20 ℃/s ,a prop-er amount of fine particle TiC can be precipitated and the rate of TiC (fine )/TiC (total )is high ,which arebeneficial to increase strength and toughness of steel. More Ti-content or cooling slowly will preciprtatemore coarse particle TiC which decreaces toughness severely. The proposed methods for quantitativephase analysis of titanium in steel are given in detail.
文摘The measured results show that the overexpanded supersonic jet velocity produced by low stagnation pressure (0.53 MPa) attenuates quickly, deviates greatly with smaller impact area and large energy loss. According to the measured results and the analysis of lashing energy of jet on the bath, the technological parameters of nitrogen flow in slag splashing were proposed.
文摘Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃. The transpassive dissolution potential of the alloy matrix under above conditions is about 1 140 mV (SCE), at which GCP phase is in passive state and can be isolated from the alloy.[WT5”HZ〗
文摘The application of the hot-rolled micronlloyed medium-carbon steel is limited due to its lower toughness compared with quenched and tempered steels.A high strength microalloyed medium-carbon steel has been developed to meet the increasing demand for eliminating heat treatment.The effects of chemical compositions,hot-deforming temperatures and cooling rates after hot-deforming on mechanical properties of the steel were investigated.Attention was given to the steel toughness above the required value for safety components in application.The basic microstructural variables controlling the properties were discussed.It is demonstrated that toughness and machinability can be improved through the addition of 0.5%Si,0.5%S and 0.01%Ti.Toughness can be further improved by controlling hot-deforming temperature and subsequent cooling rate.
基金supported by the National Natural Science Foundation of China
文摘Thermodynamics of Cu-Ce-O,Cu-Ce-S and Cu-Ce-0-S solutions at 1200℃ were studied by using solid electrolyte cell and chemical equilibrium method.The equilibrium constant of deoxidation,desulfurization and deoxysulfurization by Ce,the Gibbs standard reaction free energies of the formation of Ce_2O_3,CeS and Ce_2O_2S in Cu-base solution,activity interaction coefficients of S and Ce,temperature dependence of standard reaction free energy of solution of Ce in Cu,self-interaction coefficients of Ce in liquid Cu have been obtained.The phase precipitation diagram for Cu-CeS-O system has been plotted.The thermodynamic condition of the existence of Ce_2O_3,CeS and Ce_2O_2S in liquid Cu has been determined.It provides the basis for predicting the sequence and the type of equilibrium inclusions of Ce formed in Cu-base solution.
文摘With specially designed hot rolling test equipment,the surface deterioration process of hot rolling mill rolls can be simulated and representative samples were obtained.Thus a series of micro-analyses can be done onto the sample's worn surface,including wear loss,worn surface morphology,wear mode,oxidation and other influences from environment conditions.A leading study has been done with a high chromium cast iron to show the rolling test conditions and the methodologies of follow-up investigations for all the above-mentioned micro-analyses.Primary results have shown that high chromium iron roll may undergo complex degrading mechanism,and most of them can be investigated with the help of this research method-
文摘By technological experiments on bottom pulverized coal injection in a 10 t converter,the metallurgical reaction of continuous coal-oxygen injected into molten steel was studied.An assumption of direct burning of coal in molten steel is proposed and the result that low carbon steel can also be produced with coal injection is explained.The formulae for decarburization of melting bath were given.The apparent desulphurization rate constant is measured and activation energy of dephosphorization calculated.The influence of coal injection on nitrogen pick-up is studied too.
文摘By using a reformed laboratory rolling mill,hot wear test under near service conditions has been carried out to examine the wear mechanisms of high chromium iron roll.Each time after being rolled up to a given cycle,the worn morphology of roll surface was examined under SEM and occasionally by AES.Based on rolling conditions and lasting of in-service time,various wear characteristics have been identified distinctly.It involves abrasive wear and oxidation wear for matrix phase,fatigue wear,polishing wear and grain pull-out wear for carbides,smear adhesive wear,chemical wear,and in extreme case,plasticity-dominated wear.At the same time,wear type is also discussed compatibly in terms of abrasive wear,fatigue wear,as well as chemical wear according to conventional classification.And only in an extreme situation,i.e.rolling without cooling water,adhesive wear may partially be involved.At anytime under specified conditions,there are always several wear mechanisms occurring simultaneously,but usually only one of them can be identified as the dominant mode.And finally a wear mechanism figure can be depicted to qualitatively describe the relationship among them.
文摘The metallurgical properties of cold bound pellet were tested and analysed, and the behaviour and characters of reduction in the shaft were further investigated on the basis of analysis. The experimental results indicated that the metallurgical properties of cold bound pellet could satisfy the demands of the shaft direct reduction. The reduction of ferrous oxide with gas was taken as the domination. The reduction ratio of ferrous oxide with fixed carbon increased with the raising of temperature, and most part of the carbon remained in metallized pellet. The shaft could be smoothly operated to obtain rather higher constant utilization.
文摘Corrosion behavior of four oxide dispersion strengthened(ODS) ferritic alloys exposed in thermal convective liquid sodium loop for 4 000 h was examined.Surface observation results reveal that coral-like surfaces with deposit initially formed on surfaces of all exposed specimens.In tested alloy S2,χ-phase precipitated in specimen center,and a depleted χ- phase zone formed near the specimen surface.There is a transition area between the surface and center.In the other tested alloys,no notable change on microstructure was observed.Grain boundary attack was not found in any of the tested specimens.Tensile test results indicate that sodium corrosion of the four ODS ferritic alloys for 3 000 h had no notable effect on their tensile properties.
