摘要
采用DIL 805A动态热膨胀相变仪研究了SA508 Gr.4N钢贝氏体的TTT曲线和等温相变动力学。结果表明:试验钢的等温贝氏体相变动力学符合Johnson-Mehl型方程,最大相变速率随等温温度的升高而减小。试验钢的贝氏体转变温度区间为360~450℃,最大贝氏体转变量随等温温度的升高而降低。结合热膨胀曲线和室温下的组织分析表明,SA508 Gr.4N钢贝氏体转变不完全,等温结束后未转变的奥氏体在冷却过程中转变为M-A岛。在等温温度高于450℃保温6 h的过程中无珠光体和铁素体相变发生,当等温温度低于M_(s)点时先发生马氏体相变,随后在等温过程中发生贝氏体转变。
The TTT curves and isothermal transformation kinetics of bainite in SA508 Gr.4N steel were studied by DIL 805A dynamic thermal expansion transformation instrument.The results show that the isothermal bainite transformation kinetics of the experimental steel conforms to the Johnson-Mehl equation,and the maximum transformation rate decreases with the increase of isothermal temperature.The bainite transformation temperature range of the experimental steel is 360-450℃,and the maximum bainite transformation decreases with the increase of isothermal temperature.Combined with the thermal expansion curve and the microstructure analysis at room temperature,the bainite transformation of the SA508 Gr.4N steel is incomplete,and the untransformed austenite changes to M-A island during cooling.No pearlite and ferrite transformation occurs during isothermal at temperature higher than 450℃for 6 h.When the isothermal temperature is lower than M_(s) point,martensite transformation occurs first,and then bainite transformation occurs in the isothermal process.
作者
陆书萌
万莉
卜恒勇
李绍宏
李萌蘖
熊茹
郑善举
LU Shu-meng;WAN Li;BU Heng-yong;LI Shao-hong;LI Meng-nie;XIONG Ru;ZHENG Shan-ju(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;State Key Laboratory for Nuclear Fuel and Materials,Nuclear Power Institute of China,Chengdu 610213,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2022年第3期120-127,共8页
Transactions of Materials and Heat Treatment
基金
反应堆燃料及材料重点试验室开发基金(STRFML-2020-03)
云南省基础研究计划项目(202101AU070152)。
