The deoxidation behaviors of alloys bearing barium in pipe steel were researched with MgO crucible under argon atmosphere in MoSi2 furnace at 1 873 K.The total oxygen contents of molten steel,the distribution,size and...The deoxidation behaviors of alloys bearing barium in pipe steel were researched with MgO crucible under argon atmosphere in MoSi2 furnace at 1 873 K.The total oxygen contents of molten steel,the distribution,size and morphology of deoxidation products in the steel were surveyed.The metamorphic mechanism for deoxidation products of alloy bearing barium was also discussed.The results show that applying alloy bearing barium to the pipe steel,very low total oxygen contents can be obtained,and deoxidation products,which easily float up from molten steel,can be changed into globular shape and uniformly distributed in steel.The equilibrium time of total oxygen is about 25 min,and the terminal total oxygen contents range from 0.002 0%to 0.002 2% after treating with SiCa wire.The best deoxidizers are SiAlBaCa and SiAlBaCaSr.展开更多
Duplex NiP/TiN coatings consisting of the electroless intermediate layers and the physical vapor deposition(PVD) top layers were fabricated on the AA6061 aluminum alloy in order to enhance the load bearing capacity. T...Duplex NiP/TiN coatings consisting of the electroless intermediate layers and the physical vapor deposition(PVD) top layers were fabricated on the AA6061 aluminum alloy in order to enhance the load bearing capacity. The main objective of this study was to model the load bearing based on the thickness, adhesion and elastic modulus of the coatings. For this purpose, partial least square(PLS) and support vector regression(SVR) approaches were employed.The results showed that both models had an acceptable performance;however, the PLS model outperformed SVR. The correlation coefficients between thickness, adhesion and elastic modulus with load bearing were 0.841, 0.8092 and 0.7657, respectively;so, thickness had the greatest effect on the load bearing capacity. The composition and structure of the samples were evaluated using XRD and SEM. The load capacity of the coated samples was also discussed based on the wear and adhesion evaluations. Dry sliding wear tests, under a load of 2 N and a sliding distance of 100 m,demonstrated the complete destruction of the coated specimens with low load capacity. The samples with high load capacity showed not only a superior tribological performance, but also a remarkable adhesion according to the Rockwell superficial hardness test.展开更多
The influences of lubricating additives on the tribological behavior of lead, tin, copper base bearing alloys-0.45%C steel rubbing pairs under the condition of boundary lubrication were researched. The results show th...The influences of lubricating additives on the tribological behavior of lead, tin, copper base bearing alloys-0.45%C steel rubbing pairs under the condition of boundary lubrication were researched. The results show that because of the difference of physical chemistry performance at bearing alloys and steel, some conventional lubricating additives which is beneficial to steel-steel rubbing pairs is harmful to these bearing alloys-steel rubbing pairs,and the wear volume can be increase by 7 times under the test condition. The measure results of contact resistance during the test process show that the higher the contact resistance at rubbing surface, the better the tribological behavior of tribo-system. Moreover for the lead base and tin base bearing alloys-0.45%C steel rubbed pairs, the thicker the compact oxide layer of steel surface, the larger the friction coefficient and wear volume, which demonstrates that oxidation wear plays an important part in the wear process.展开更多
Two commercial grade aluminum based immiscible bearing alloys were spray-deposited using convergent-divergent type of nozzle. The processing parameters for spray-deposition were adjusted in such a way that most of the...Two commercial grade aluminum based immiscible bearing alloys were spray-deposited using convergent-divergent type of nozzle. The processing parameters for spray-deposition were adjusted in such a way that most of the droplets arrived on the deposition substrate in either liquid or semi-liquid state. The microstructural features of spray-formed and as-cast alloys are compared. In spray-formed alloys equiaxed grains were observed. The cell boundaries and intercellular regions were observed to be decorated with sub-micron sized particles whereas in normal casting the second phase was observed to be segregated along grain boundaries. The morphology and distribution of second phase were observed to have similarity with those in over-spread and atomized powders produced under similar processing conditions. The microstructural features observed with variation in spray conditions are discussed in detail.展开更多
The new preparation method of scandium bearing master alloys, in which scandium oxide was fluorinated by reaction with NH 4HF 2 and then reduced by aluminum magnesium in fused salt containing alkali and alkaline f...The new preparation method of scandium bearing master alloys, in which scandium oxide was fluorinated by reaction with NH 4HF 2 and then reduced by aluminum magnesium in fused salt containing alkali and alkaline fluoride under atmosphere, was studied. The effect of sorts of metallic reductive and technique conditions such as reducing temperature and time on the recovery of Sc was discussed. When the liquid aluminum magnesium was used as the reductive agent, the all recovery exceeds 80% and the concentration of Sc in master alloy prepared exceeds 1.9%. The best reducing reaction temperature and time are 1100 K and 40 min respectively. The newly produced Sc from reduction combines with Al to produce the stable compound Al 3Sc, so the reduction progress is sustained and the recovery of Sc is increased.展开更多
The results of the contacting fatigue tests for Cu-22%Pb plain bearing alloy show that the fa- tigue failure behavior of the alloy is related to the distribution of Pb particles.Both the addi- tions of mischmetal and ...The results of the contacting fatigue tests for Cu-22%Pb plain bearing alloy show that the fa- tigue failure behavior of the alloy is related to the distribution of Pb particles.Both the addi- tions of mischmetal and sulphur can refine the Pb particles.However,mischmetal improves and sulphur deteriorates the fatigue property of the alloy.展开更多
The mechanical behavior and indentation creep of Al-20 wt%<span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "=""...The mechanical behavior and indentation creep of Al-20 wt%<span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">Zn bearing al</span><span style="white-space:normal;font-family:;" "="">loy</span><span style="white-space:normal;font-family:" color:#ff0000;"=""> </span><span style="white-space:normal;font-family:;" "="">ha</span><span style="white-space:normal;font-family:宋体;">s</span><span style="white-space:normal;font-family:;" "=""> been modified with adding 0.2 wt%, 0.5 wt%, 1 wt%, 1.5 wt% Sn. T</span><span style="white-space:normal;font-family:;" "="">hese bearing alloys were prepared by melt spinning technique. The scanning electron</span><span style="white-space:normal;font-family:;" "=""> microscopy (SEM) was used to study the morphology of th</span><span style="white-space:normal;font-family:;" "="">e melt spun alloys and x-ray diffractometer (XRD) for the identification of the phases pre</span><span style="white-space:normal;font-family:宋体;">- </span><span style="white-space:normal;font-family:;" "="">sent in these melt-spun bearing alloys. The results show that the structure of Al</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"="">80-x</span></sub><span style="white-space:normal;font-family:;" "="">-Zn</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"="">20</span></sub><span style="white-space:normal;font-family:;" "="">-Sn</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"="">X</span></sub><span style="white-space:normal;font-family:;" "=""> (X = 0.2%, 0.5%, 1%</span><span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">and 1.5%) bearing alloys is characterized by the presence of </span><i style="white-space:normal;"><span style="font-family:;" "="">α</span></i><span style="white-space:normal;font-family:;" "="">-Al of FCC structure and SnZn</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"=""> </span></sub><span style="white-space:normal;font-family:;" "="">intermetallic compound </span><span style="white-space:normal;font-family:;" "="">of anorthic structure. The Al-20Zn-1.5Sn has a smaller crystallite size and gr</span><span style="white-space:normal;font-family:;" "="">ain size as indicated from X-ray and SEM analysis respectively, which lead</span><span style="white-space:normal;font-family:宋体;">ing</span><span style="white-space:normal;font-family:;" "=""> to </span><span style="white-space:normal;font-family:;" "="">the enhancement of the mechanical properties. The mechanical properties an</span><span style="white-space:normal;font-family:;" "="">d indentation creep of these bearing alloys were studied by tensile test machine </span><span style="white-space:normal;font-family:;" "="">and vickers indentation testing at room temperature, respectively. The Al-</span><span style="white-space:normal;font-family:;" "="">20Zn-</span><span style="white-space:normal;font-family:;" "="">1.5Sn has higher hardness value and creep resistance than other alloys. This was attributed to the strengthen effect of Sn as a strong solid solution element in Al-matrix. The stress exponent values in the range 2.4</span><span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">-</span><span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">4.2 indicate that the grain boundary sliding is the possible mechanism during room temperature creep deformation of melt-spun Al-Zn-Sn bearing alloys.</span>展开更多
The deoxidation, desulfurization, dephosphorization, microstructure, and mechanical properties of steels treated by barium-bearing alloys were investigated in laboratory and by industrial tests. The results show that ...The deoxidation, desulfurization, dephosphorization, microstructure, and mechanical properties of steels treated by barium-bearing alloys were investigated in laboratory and by industrial tests. The results show that barium takes part in the deoxidation reaction at the beginning of the experiments, generating oxide and sulfide compound inclusions, which easily float up from the molten steel, leading to the rapid reduction of total oxygen content to a very low level. The desulfurization and dephosphorization capabilities of calcium-bearing alloys increase with the addition of barium. The results of OM and SEM observations and mechanical property tests show that the structure of the steel treated by barium-bearing alloys is refined remarkably, the lamellar thickness of pearlitic structure decreases, and the pearlitic morphology shows clustering distribution. Less barium exists in steel substrate and the enrichment of barium-bearing precipitated phase mostly occurs in grain boundary and phase boundary, which can prevent the movement of grain boundary and dislocation during the heat treatment and the deformation processes. Therefore, the strength and toughness of barium-treated steels are improved by the effect of grain-boundary strengthening and nail-prick dislocation.展开更多
In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which ...In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as well.Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and stops.Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the paper.The tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/Babbitt.The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction regime.Analysis of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific conditions.More specifically,the DLC/steel bearing was demonstrating superior performance,i.e.lower friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.展开更多
基金Item Sponsored by National Natural Science Foundation of China(50174012)Baoshan Iron and Steel Group Co
文摘The deoxidation behaviors of alloys bearing barium in pipe steel were researched with MgO crucible under argon atmosphere in MoSi2 furnace at 1 873 K.The total oxygen contents of molten steel,the distribution,size and morphology of deoxidation products in the steel were surveyed.The metamorphic mechanism for deoxidation products of alloy bearing barium was also discussed.The results show that applying alloy bearing barium to the pipe steel,very low total oxygen contents can be obtained,and deoxidation products,which easily float up from molten steel,can be changed into globular shape and uniformly distributed in steel.The equilibrium time of total oxygen is about 25 min,and the terminal total oxygen contents range from 0.002 0%to 0.002 2% after treating with SiCa wire.The best deoxidizers are SiAlBaCa and SiAlBaCaSr.
文摘Duplex NiP/TiN coatings consisting of the electroless intermediate layers and the physical vapor deposition(PVD) top layers were fabricated on the AA6061 aluminum alloy in order to enhance the load bearing capacity. The main objective of this study was to model the load bearing based on the thickness, adhesion and elastic modulus of the coatings. For this purpose, partial least square(PLS) and support vector regression(SVR) approaches were employed.The results showed that both models had an acceptable performance;however, the PLS model outperformed SVR. The correlation coefficients between thickness, adhesion and elastic modulus with load bearing were 0.841, 0.8092 and 0.7657, respectively;so, thickness had the greatest effect on the load bearing capacity. The composition and structure of the samples were evaluated using XRD and SEM. The load capacity of the coated samples was also discussed based on the wear and adhesion evaluations. Dry sliding wear tests, under a load of 2 N and a sliding distance of 100 m,demonstrated the complete destruction of the coated specimens with low load capacity. The samples with high load capacity showed not only a superior tribological performance, but also a remarkable adhesion according to the Rockwell superficial hardness test.
文摘The influences of lubricating additives on the tribological behavior of lead, tin, copper base bearing alloys-0.45%C steel rubbing pairs under the condition of boundary lubrication were researched. The results show that because of the difference of physical chemistry performance at bearing alloys and steel, some conventional lubricating additives which is beneficial to steel-steel rubbing pairs is harmful to these bearing alloys-steel rubbing pairs,and the wear volume can be increase by 7 times under the test condition. The measure results of contact resistance during the test process show that the higher the contact resistance at rubbing surface, the better the tribological behavior of tribo-system. Moreover for the lead base and tin base bearing alloys-0.45%C steel rubbed pairs, the thicker the compact oxide layer of steel surface, the larger the friction coefficient and wear volume, which demonstrates that oxidation wear plays an important part in the wear process.
文摘Two commercial grade aluminum based immiscible bearing alloys were spray-deposited using convergent-divergent type of nozzle. The processing parameters for spray-deposition were adjusted in such a way that most of the droplets arrived on the deposition substrate in either liquid or semi-liquid state. The microstructural features of spray-formed and as-cast alloys are compared. In spray-formed alloys equiaxed grains were observed. The cell boundaries and intercellular regions were observed to be decorated with sub-micron sized particles whereas in normal casting the second phase was observed to be segregated along grain boundaries. The morphology and distribution of second phase were observed to have similarity with those in over-spread and atomized powders produced under similar processing conditions. The microstructural features observed with variation in spray conditions are discussed in detail.
文摘The new preparation method of scandium bearing master alloys, in which scandium oxide was fluorinated by reaction with NH 4HF 2 and then reduced by aluminum magnesium in fused salt containing alkali and alkaline fluoride under atmosphere, was studied. The effect of sorts of metallic reductive and technique conditions such as reducing temperature and time on the recovery of Sc was discussed. When the liquid aluminum magnesium was used as the reductive agent, the all recovery exceeds 80% and the concentration of Sc in master alloy prepared exceeds 1.9%. The best reducing reaction temperature and time are 1100 K and 40 min respectively. The newly produced Sc from reduction combines with Al to produce the stable compound Al 3Sc, so the reduction progress is sustained and the recovery of Sc is increased.
文摘The results of the contacting fatigue tests for Cu-22%Pb plain bearing alloy show that the fa- tigue failure behavior of the alloy is related to the distribution of Pb particles.Both the addi- tions of mischmetal and sulphur can refine the Pb particles.However,mischmetal improves and sulphur deteriorates the fatigue property of the alloy.
文摘The mechanical behavior and indentation creep of Al-20 wt%<span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">Zn bearing al</span><span style="white-space:normal;font-family:;" "="">loy</span><span style="white-space:normal;font-family:" color:#ff0000;"=""> </span><span style="white-space:normal;font-family:;" "="">ha</span><span style="white-space:normal;font-family:宋体;">s</span><span style="white-space:normal;font-family:;" "=""> been modified with adding 0.2 wt%, 0.5 wt%, 1 wt%, 1.5 wt% Sn. T</span><span style="white-space:normal;font-family:;" "="">hese bearing alloys were prepared by melt spinning technique. The scanning electron</span><span style="white-space:normal;font-family:;" "=""> microscopy (SEM) was used to study the morphology of th</span><span style="white-space:normal;font-family:;" "="">e melt spun alloys and x-ray diffractometer (XRD) for the identification of the phases pre</span><span style="white-space:normal;font-family:宋体;">- </span><span style="white-space:normal;font-family:;" "="">sent in these melt-spun bearing alloys. The results show that the structure of Al</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"="">80-x</span></sub><span style="white-space:normal;font-family:;" "="">-Zn</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"="">20</span></sub><span style="white-space:normal;font-family:;" "="">-Sn</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"="">X</span></sub><span style="white-space:normal;font-family:;" "=""> (X = 0.2%, 0.5%, 1%</span><span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">and 1.5%) bearing alloys is characterized by the presence of </span><i style="white-space:normal;"><span style="font-family:;" "="">α</span></i><span style="white-space:normal;font-family:;" "="">-Al of FCC structure and SnZn</span><sub style="white-space:normal;"><span style="font-family:" vertical-align:sub;"=""> </span></sub><span style="white-space:normal;font-family:;" "="">intermetallic compound </span><span style="white-space:normal;font-family:;" "="">of anorthic structure. The Al-20Zn-1.5Sn has a smaller crystallite size and gr</span><span style="white-space:normal;font-family:;" "="">ain size as indicated from X-ray and SEM analysis respectively, which lead</span><span style="white-space:normal;font-family:宋体;">ing</span><span style="white-space:normal;font-family:;" "=""> to </span><span style="white-space:normal;font-family:;" "="">the enhancement of the mechanical properties. The mechanical properties an</span><span style="white-space:normal;font-family:;" "="">d indentation creep of these bearing alloys were studied by tensile test machine </span><span style="white-space:normal;font-family:;" "="">and vickers indentation testing at room temperature, respectively. The Al-</span><span style="white-space:normal;font-family:;" "="">20Zn-</span><span style="white-space:normal;font-family:;" "="">1.5Sn has higher hardness value and creep resistance than other alloys. This was attributed to the strengthen effect of Sn as a strong solid solution element in Al-matrix. The stress exponent values in the range 2.4</span><span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">-</span><span style="white-space:normal;font-family:宋体;"> </span><span style="white-space:normal;font-family:;" "="">4.2 indicate that the grain boundary sliding is the possible mechanism during room temperature creep deformation of melt-spun Al-Zn-Sn bearing alloys.</span>
基金the National Natural Science Foundation of China and Baosteel Group Corporation(No.50174012)
文摘The deoxidation, desulfurization, dephosphorization, microstructure, and mechanical properties of steels treated by barium-bearing alloys were investigated in laboratory and by industrial tests. The results show that barium takes part in the deoxidation reaction at the beginning of the experiments, generating oxide and sulfide compound inclusions, which easily float up from the molten steel, leading to the rapid reduction of total oxygen content to a very low level. The desulfurization and dephosphorization capabilities of calcium-bearing alloys increase with the addition of barium. The results of OM and SEM observations and mechanical property tests show that the structure of the steel treated by barium-bearing alloys is refined remarkably, the lamellar thickness of pearlitic structure decreases, and the pearlitic morphology shows clustering distribution. Less barium exists in steel substrate and the enrichment of barium-bearing precipitated phase mostly occurs in grain boundary and phase boundary, which can prevent the movement of grain boundary and dislocation during the heat treatment and the deformation processes. Therefore, the strength and toughness of barium-treated steels are improved by the effect of grain-boundary strengthening and nail-prick dislocation.
文摘In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as well.Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and stops.Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the paper.The tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/Babbitt.The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction regime.Analysis of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific conditions.More specifically,the DLC/steel bearing was demonstrating superior performance,i.e.lower friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.