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
The ultra-fast cooling technology of large section bars and the microstrueture for different cooling patterns were studied by optical microscope, transmission electron microscope and energy spectrometer. The results i...The ultra-fast cooling technology of large section bars and the microstrueture for different cooling patterns were studied by optical microscope, transmission electron microscope and energy spectrometer. The results indicated that the large section bars were passed through the zone of secondary carbide precipitation quickly by ultra-fast cooling technology （UFC） at instantaneous cooling rate of about 200 ℃/s and the finishing cooling temperature was higher than Ms. The lamellar spacing of pearlite decreased and the microhardness increased with decreasing the rereddening temperature. The precipitation of network carbide was restrained when re-reddening temperature was 690 ℃. And fine laminated pearlite was obtained through transformation of pseudopearlition that induced the reduction of the diameter of pearlite grain and refinement of the lamellar spacing of pearlite, so ideal microstructures of promoting spheroidizing annealing were obtained.展开更多
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.
基金Sponsored by National Natural Science Foundation of China(50334010)
文摘The ultra-fast cooling technology of large section bars and the microstrueture for different cooling patterns were studied by optical microscope, transmission electron microscope and energy spectrometer. The results indicated that the large section bars were passed through the zone of secondary carbide precipitation quickly by ultra-fast cooling technology （UFC） at instantaneous cooling rate of about 200 ℃/s and the finishing cooling temperature was higher than Ms. The lamellar spacing of pearlite decreased and the microhardness increased with decreasing the rereddening temperature. The precipitation of network carbide was restrained when re-reddening temperature was 690 ℃. And fine laminated pearlite was obtained through transformation of pseudopearlition that induced the reduction of the diameter of pearlite grain and refinement of the lamellar spacing of pearlite, so ideal microstructures of promoting spheroidizing annealing were obtained.
