摘要
采用热膨胀法结合硬度测试得到耐候钢未变形和变形奥氏体的连续冷却转变曲线;用光学显微镜和透射电镜分析了冷却速率、变形条件对显微组织的影响。结果表明:变形奥氏体与未变形的相比,铁素体+珠光体相变区向左上方移动,获得铁素体+珠光体的临界冷速增大;变形奥氏体的位错缠结抑制了贝氏体长大,细化了相变后的显微组织;在冷速大于15℃/s时,获得板条状贝氏体,第二相是渗碳体;在冷速5～10℃/s的范围内获得粒状贝氏体,第二相为基体上分布的马氏体/奥氏体岛。
The continuous cooling transformation （CCT） diagrams of austenite non-deformation and deformed at 950 ℃ were constructed by means of a combined dilatometry and Vickers-hardness measurement for a weathering steel. Optical microscope and TEM were employed to investigate the influence of cooling rate, deformation process on the transformation behavior and rnicrostructure. Results show that the deformation promotes the area of ferrite move towards top left comer, leading to the increase of critical cooling rate obtained ferrite plus pearlite. The deformation on austenite stifled the growth of bainitic ferrite by tangled dislocations resulting the refinement of microstructure. Lath-like microstructure observed at the cooling rate above 15 ℃/s mainly is revealed to consist of bainitic-ferrite with cementite. Granular microstructure observed at the cooling rate ranging from 5- 10 ℃/s is characterized to be martensite-ausenite constituent islands.
出处
《机械工程材料》
CAS
CSCD
北大核心
2007年第5期72-75,78,共5页
Materials For Mechanical Engineering
基金
国家二期973计划资助项目(2004CB619101)
关键词
耐候钢
奥氏体转变
连续冷却转变曲线
weathering steel
austenite transformation
continuous cooling transformation curve
