The effect of alloy segregation and delta （δ） ferrite contents on surface cracking of three standard （i.e. AISI 304L, AISI 310S and AISI 321） and two low nickel （i.e. LNi-1 and LNi-0.3） austenitic stainless ste...The effect of alloy segregation and delta （δ） ferrite contents on surface cracking of three standard （i.e. AISI 304L, AISI 310S and AISI 321） and two low nickel （i.e. LNi-1 and LNi-0.3） austenitic stainless steels （ASS） during hot roiling was investigated using optical microscopy （OM）, automatic image analyzer, scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX） and electron probe micro analyzer （EPMA）. It was observed that the amount of 6-ferrite varied among different grades and also distributed heterogeneously across the width of the steel plates. In general, low nickel ASS showed higher amount of 6-ferrite compared to the standard ASS grades. The tendency to surface cracking during hot rolling gradually increased with increasing 6-ferrite content. Interestingly, carbon and nitrogen exerted maximum effect on 6-ferrite formation. The higher carbon and nitrogen content in the steel decreased 6-ferMte content. In addition, the segregation of Cu and Mn plays significant role in low nickel ASS and Ni-Cr in case of standard ASS has profound effect on surface cracking of the steel plates. A possible cause of surface crack formation/origination in steel plates during hot rolling was discussed.展开更多
The radial growth of ＆phase in Fe 0.15 ℃ 0.8 ~ Mn steel during solidification was in-situ observed under a high temperature confocal scanning laser microscope （HTCSLM）. The correlation between radial growth rate o...The radial growth of ＆phase in Fe 0.15 ℃ 0.8 ~ Mn steel during solidification was in-situ observed under a high temperature confocal scanning laser microscope （HTCSLM）. The correlation between radial growth rate of cylindrical solid and time in melt was investigated, and the expression was deduced. The results indicate that the ra- dius of cellular B-phase rapidly enlarges at the beginning, and then the enlargement amplitude gradually declines. The variation of radial growth rate vs time is the same for each cellular δ- phase, and the radial growth rate of c3-phase rapidly declines to about 1.5 μm/s within 10 s at a cooling rate of 2.7 K/min, after that the growth rate slowly falls. The experimental data of the radial growth rate of cellular δ- phase are consistent with the calculation results for Fe 0. 15℃ -0.8%Mn steel .展开更多
文摘The effect of alloy segregation and delta （δ） ferrite contents on surface cracking of three standard （i.e. AISI 304L, AISI 310S and AISI 321） and two low nickel （i.e. LNi-1 and LNi-0.3） austenitic stainless steels （ASS） during hot roiling was investigated using optical microscopy （OM）, automatic image analyzer, scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX） and electron probe micro analyzer （EPMA）. It was observed that the amount of 6-ferrite varied among different grades and also distributed heterogeneously across the width of the steel plates. In general, low nickel ASS showed higher amount of 6-ferrite compared to the standard ASS grades. The tendency to surface cracking during hot rolling gradually increased with increasing 6-ferrite content. Interestingly, carbon and nitrogen exerted maximum effect on 6-ferrite formation. The higher carbon and nitrogen content in the steel decreased 6-ferMte content. In addition, the segregation of Cu and Mn plays significant role in low nickel ASS and Ni-Cr in case of standard ASS has profound effect on surface cracking of the steel plates. A possible cause of surface crack formation/origination in steel plates during hot rolling was discussed.
基金Sponsored by National Natural Science Foundation of China(50874060)Program of Excellent Talents of Liaoning Province in University of China(LR201019)
文摘The radial growth of ＆phase in Fe 0.15 ℃ 0.8 ~ Mn steel during solidification was in-situ observed under a high temperature confocal scanning laser microscope （HTCSLM）. The correlation between radial growth rate of cylindrical solid and time in melt was investigated, and the expression was deduced. The results indicate that the ra- dius of cellular B-phase rapidly enlarges at the beginning, and then the enlargement amplitude gradually declines. The variation of radial growth rate vs time is the same for each cellular δ- phase, and the radial growth rate of c3-phase rapidly declines to about 1.5 μm/s within 10 s at a cooling rate of 2.7 K/min, after that the growth rate slowly falls. The experimental data of the radial growth rate of cellular δ- phase are consistent with the calculation results for Fe 0. 15℃ -0.8%Mn steel .
