摘要
针对HQ785试验钢,采用Gleeble-1500热模拟试验机进行了单向外加拉/压应力下的等温相变实验,等温温度分别是425℃和475℃,所加应力依次为20、40和60 MPa,通过光学显微镜和透射电镜对相变后的显微组织进行了观察与分析。结果表明,外加应力作用下的等温相变组织是粒状贝氏体,外加应力使无明显晶界的显微组织转变为晶界清晰的细小晶粒;粒状贝氏体中贝氏体铁素体的亚单元,随着外加拉应力的增加逐渐由条片向块状变化,随着外加压应力的增加逐渐由块状向条片变化。
Isothermal transformation tests of HQ785 steel were carried out on a Gleeble-1500 thermo-mechanical simulator at 425 ℃ and 475 ℃ under uniaxial tension/compression stresses of 20 MPa,40 MPa and 60 MPa,respectively.Microstructure of the steel after phase transformation was observed and analyzed by OM and TEM.The results show that the isothermal transformation microstructure is granular bainite under the external stress,the external stresses vary the transformation microstructure from no distinct grain boundary to fine grains with clear grain boundary.External stresses make the sub-units shape of granular bainitic ferrite change,the lath sub-units change to blocky sub-units with the external tensile stress increasing and the block-shaped sub-units change to lath sub-units with the external compression stress increasing for the HQ785 steel during isothermal bainitic transformation.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2011年第7期67-72,共6页
Transactions of Materials and Heat Treatment
