期刊
MATERIALS CHARACTERIZATION
卷 149, 期 -, 页码 165-183出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.matchar.2019.01.029
关键词
Induction hardening; Heating rate; Cementite dissolution; Prior austenite grain size; Dilatometry
类别
资金
- European Commission [675715]
- Marie Curie Actions (MSCA) [675715] Funding Source: Marie Curie Actions (MSCA)
The induction hardening behavior of a new, hot-rolled 0.4 wt% carbon steel with the two different starting microstructures of upper and lower bainite has been simulated using a Gleeble 3800. The effect of heating rate in the range 1-500 degrees C/s on austenite grain size distribution has been rationalized. Dilatometry together with Scanning Electron Microscopy combined with Electron Backscatter Diffraction analyses and thermodynamic simulations provide insight into the austenite formation mechanisms that operate at different heating rates. Two main mechanisms of austenite formation during re-austenitization were identified: diffusional and diffusionless (massive). At conventional (1-5 degrees C/s) and fast (10-50 degrees C/s) heating rates the austenite formation mechanism and kinetics are controlled by diffusion, whereas at ultrafast heating rates (100-500 degrees C/s) the formation of austenite starts by diffusion control, but is later overtaken by a massive transformation mechanism. Comprehensive thermodynamic descriptions of the influence of cementite on austenite formation are discussed. The finest austenite grain size and the highest final hardness are achieved with a lower bainite starting microstructure processed with a heating rate of 50 degrees C/s to an austenitization temperature of 850 degrees C followed by cooling at 60 degrees C/s.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据