GH4033合金粗轧加热过程晶粒长大模型

Grain growth model of GH4033 alloy in reheating process

以GH4033合金锻坯为研究对象,在850~1200℃的温度范围内,借助激光共聚焦高温显微镜研究了加热温度和保温时间对GH4033合金锻坯晶粒尺寸变化的影响,推导并验证了具有普适意义的适合GH4033合金锻坯粗轧加热过程的晶粒长大模型。研究结果表明:随加热时间的延长,在850~1050℃加热时,晶粒尺寸变化不显著,且呈线性长大;1100~1200℃加热时,晶粒尺寸呈抛物线性长大,加热时间低于30 min时,晶粒尺寸随温度升高急剧长大,30 min后晶粒尺寸变化不显著,45 min后出现混晶现象。用于热加工的锻坯,加热温度低于1100℃时,有利于细化晶粒;加热温度高于1100℃时,保证坯料断面均温时间处于30~45 min可有效避免混晶。

GH4033 alloy forged slab was used as experimental material, and the effects of reheating temperature and holding time on grain growth of the alloy were investigated by the confocal laser scanning microscopy. A universal model was developed and verified for the grain growth of the GH4033 alloy forged slab in reheating process. The results show that with the increasing of holding time, the grain size exhibits no remarkable change and presents a linear trend when reheated at temperature range from 850 ℃ to 1100 ℃. A parabolic trend of the grain growth is observed as reheating temperature is from 1100 ℃ to 1200 ℃ , and the grain size sharply grows as the holding time is within 30 min and slowly grows as that is more than 30 min, even the mixed grain appears as the holding time is more than 45 min. For the reheated forged billet, it is beneficial to the grain refinement as the reheating temperature is not more than 1100 ℃. If the reheating temperature is more than 1100 ℃ , it is effective to avoid mixed grain as the holding time between 30-45 min to ensure uniform temperature of the billet.