DTA, thermal expansion, XRD, and SEM were used to evaluate the effect of quenching temperature on the mechanical properties and microstructure of a novel sintered steel Fe-6Co-1Ni-5Cr-5Mo-1C. Lattice parameters and th...DTA, thermal expansion, XRD, and SEM were used to evaluate the effect of quenching temperature on the mechanical properties and microstructure of a novel sintered steel Fe-6Co-1Ni-5Cr-5Mo-1C. Lattice parameters and the mass fraction of carbon dissolved in the matrix of the steel quenched were investigated. It is discovered that the hardness of the steel increases with quenching temperature in the range of 840-900℃ and remains constant in the range of 900 to 1100℃. It decreases rapidly when the temperature is higher than 1100℃. The mass fraction of carbon dissolved in the matrix of the steel quenched at 840℃ is 0.38, but when the quenching temperature is increased to 1150℃, it increases to 0.98. The carbides formed during sintering are still present at grain boundaries and in the matrix of the steel quenched at low quenching temperatures, such as 840℃. When the quenching temperature is increased to 1150℃, most of the carbides at grain boundaries are dissolved with just a small amount of spherical M23C6 existing in the matrix of the quenched steel.展开更多
The microstructures and impact absorbed energies at various temperatures were investigated for steel strips hot rolled to thickness reductions of 95.5%, 96.0%, 96.5%, 97.0%, and 97.5%. Results indicate that grain refi...The microstructures and impact absorbed energies at various temperatures were investigated for steel strips hot rolled to thickness reductions of 95.5%, 96.0%, 96.5%, 97.0%, and 97.5%. Results indicate that grain refinement can be realized with an increase in hot rolling reduction. Besides, finer precipitates can be achieved with an increase in hot rolling reduction from 95.5%to 97.0%. The impact absorbed energy decreases with a decrease in testing temperature for steel strips hot rolled to 95.5%, 96.0%, and 96.5%reductions in thickness. However, in the case of steel strips hot rolled to 97.0%and 97.5%reductions in thickness, the impact absorbed energy remained almost constant with a decrease in testing temperature.展开更多
The effect of adding 0.5mass% Cu on ductility and magnetic properties of Fe-6.5Si（mass%）alloy was investigated.The alloys with and without 0.5mass% Cu addition were warm rolled into thin sheets of thickness no more ...The effect of adding 0.5mass% Cu on ductility and magnetic properties of Fe-6.5Si（mass%）alloy was investigated.The alloys with and without 0.5mass% Cu addition were warm rolled into thin sheets of thickness no more than 0.3mm at temperature below 600 ℃.It was found that the alloy with 0.5mass% Cu addition was more easily warm rolled than Cu-free alloy.Tensile tests were carried out to further investigate this phenomenon,which confirmed that the ductility of the alloy with 0.5mass% Cu addition was significantly higher than that of Cu-free alloy at 550 ℃.Based on the results of transmission electron microscopy analysis,the ductility increase of the alloy with 0.5mass% Cu addition was attributed to the effect of Cu on the promotion of dynamic recovery and suppression of long-range order in the alloy during warm rolling process.It was also observed that the iron loss was lower and inductance was higher for the alloy with 0.5 mass% Cu addition.Thus,it can be concluded that adding a suitably small amount of Cu would not only increase the ductility of Fe-6.5Si alloy at warm rolling temperatures but also improve its magnetic properties.展开更多
文摘DTA, thermal expansion, XRD, and SEM were used to evaluate the effect of quenching temperature on the mechanical properties and microstructure of a novel sintered steel Fe-6Co-1Ni-5Cr-5Mo-1C. Lattice parameters and the mass fraction of carbon dissolved in the matrix of the steel quenched were investigated. It is discovered that the hardness of the steel increases with quenching temperature in the range of 840-900℃ and remains constant in the range of 900 to 1100℃. It decreases rapidly when the temperature is higher than 1100℃. The mass fraction of carbon dissolved in the matrix of the steel quenched at 840℃ is 0.38, but when the quenching temperature is increased to 1150℃, it increases to 0.98. The carbides formed during sintering are still present at grain boundaries and in the matrix of the steel quenched at low quenching temperatures, such as 840℃. When the quenching temperature is increased to 1150℃, most of the carbides at grain boundaries are dissolved with just a small amount of spherical M23C6 existing in the matrix of the quenched steel.
文摘The microstructures and impact absorbed energies at various temperatures were investigated for steel strips hot rolled to thickness reductions of 95.5%, 96.0%, 96.5%, 97.0%, and 97.5%. Results indicate that grain refinement can be realized with an increase in hot rolling reduction. Besides, finer precipitates can be achieved with an increase in hot rolling reduction from 95.5%to 97.0%. The impact absorbed energy decreases with a decrease in testing temperature for steel strips hot rolled to 95.5%, 96.0%, and 96.5%reductions in thickness. However, in the case of steel strips hot rolled to 97.0%and 97.5%reductions in thickness, the impact absorbed energy remained almost constant with a decrease in testing temperature.
基金Item Sponsored by Natural Science Foundation of Hubei Province of China(2008CDA040)
文摘The effect of adding 0.5mass% Cu on ductility and magnetic properties of Fe-6.5Si（mass%）alloy was investigated.The alloys with and without 0.5mass% Cu addition were warm rolled into thin sheets of thickness no more than 0.3mm at temperature below 600 ℃.It was found that the alloy with 0.5mass% Cu addition was more easily warm rolled than Cu-free alloy.Tensile tests were carried out to further investigate this phenomenon,which confirmed that the ductility of the alloy with 0.5mass% Cu addition was significantly higher than that of Cu-free alloy at 550 ℃.Based on the results of transmission electron microscopy analysis,the ductility increase of the alloy with 0.5mass% Cu addition was attributed to the effect of Cu on the promotion of dynamic recovery and suppression of long-range order in the alloy during warm rolling process.It was also observed that the iron loss was lower and inductance was higher for the alloy with 0.5 mass% Cu addition.Thus,it can be concluded that adding a suitably small amount of Cu would not only increase the ductility of Fe-6.5Si alloy at warm rolling temperatures but also improve its magnetic properties.
