Effect of Precipitates on Austenite Grain Growth Behavior in a Low-Carbon Nb-V Microalloyed Steel

2017 ◽  
Vol 898 ◽  
pp. 783-790 ◽  
Author(s):  
Li Chong Zhang ◽  
Xin Li Wen ◽  
Ya Zheng Liu
Keyword(s):  
Grain Growth ◽  
Microalloyed Steel ◽  
Growth Models ◽  
Energy Dispersive Spectrometer ◽  
Growth Behavior ◽  
Low Carbon ◽  
Dissolution Temperature ◽  
Austenite Grain ◽  
Grain Growth Behavior ◽  
Austenite Grain Growth

The effect of precipitates on austenite grain growth behavior in a Nb-V microalloyed steel was investigated. The precipitates were identified by selected area electron diffraction (SAED) and energy dispersive spectrometer (EDS) analysis. Because of pinning effect of NbC and/or VC on austenite grain boundaries, grains grew slowly at 850oC-1000oC. However, when temperature reached 1050 oC, abnormal grain growth was observed, which was attributed to dissolution of NbC particles. The NbC precipitates dissolved significantly at 1150 oC. However, grain sizes were still very small. Thus, austenite grains grew rapidly at 1050-1150 oC. The fully dissolution temperature of this steel was 1150-1250oC. Finally, the relationship between grain coarsening temperature (TGC) and fully dissolution temperature (TDISS) could be illustrated as follows: 100 oC≤TDISS -TGC≤200 oC. When heating temperatures were 850-1050 oC and 1050-1250 oC, grain growth activation energies (Q) were 59945 J/mol and 135813 J/mol, respectively. The different grain growth models were mainly caused by the gradual dissolution of NbC particles.

scholarly journals Effect of Cold-Deformation on Austenite Grain Growth Behavior in Solution-Treated Low Alloy Steel

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1004 ◽  
Author(s):  
Xianguang Zhang ◽  
Kiyotaka Matsuura ◽  
Munekazu Ohno
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Grain Growth ◽  
Cold Deformation ◽  
Growth Behavior ◽  
Low Alloy Steel ◽  
Solution Treated ◽  
Austenite Grain ◽  
Grain Growth Behavior ◽  
Austenite Grain Growth

The occurrence of abnormal grain growth (AGG) of austenite during annealing is a serious problem in steels with carbide and/or nitride particles, which should be avoided from a viewpoint of mechanical properties. The effects of cold deformation prior to annealing on the occurrence of AGG have been investigated. It was found that the temperature range of the occurrence of AGG is shifted toward a low temperature region by cold deformation, and that the shift increases with the increase of the reduction ratio. The lowered AGG occurrence temperature is attributed to the fine and near-equilibrium AlN particles that are precipitated in the cold-deformed steel, which is readily dissolved during annealing. In contrast, coarse and non-equilibrium AlN particles precipitated in the undeformed steel, which is resistant to dissolution during annealing.

scholarly journals Austenite Grain Growth Behavior of AISI 4140 Alloy Steel

2013 ◽  
Vol 5 ◽  
pp. 762890 ◽  
Author(s):  
Lin Wang ◽  
Dongsheng Qian ◽  
Jun Guo ◽  
Yan Pan
Keyword(s):  
Grain Growth ◽  
Alloy Steel ◽  
Growth Behavior ◽  
Austenite Grain ◽  
Aisi 4140 ◽  
Grain Growth Behavior ◽  
Austenite Grain Growth

Effects of Rare Earths on Austenite Grain Growth Behavior in X80 Pipeline Steel

2010 ◽  
Vol 163-167 ◽  
pp. 61-65 ◽  
Author(s):  
Cheng Jun Liu ◽  
Hong Liang Liu ◽  
Mao Fa Jiang
Keyword(s):  
Grain Growth ◽  
Rare Earths ◽  
Pipeline Steel ◽  
Growth Index ◽  
Growth Behavior ◽  
Vacuum Induction Furnace ◽  
X80 Pipeline Steel ◽  
Austenite Grain ◽  
Grain Growth Behavior ◽  
Austenite Grain Growth

Accorded with the criteria the X80 pipeline steels with RE additions have been prepared with a vacuum induction furnace. The effect of rare earths (RE) on austenite grain growth behavior in pipeline steel has been discussed in this work. After hot rolled, the effect of RE on austenite grain growth behavior have been studied by the thermal simulator, scanning electron microscopy and metallographic microscope. The results indicate that RE additions inhibit the abnormal growth of austenite grain, trace RE could significantly influence the austenite grain growth behavior, and obtain fine grain size in X80 pipeline steel. For instance, the activation energy of grain growth reduced from 475 kJ/mol to 425 kJ/mol with addition of 0.0220 wt.% RE according with no deliberate RE additions, but the grain growth index increased from 3.5 to 4.5.

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