知识与财富的链接
以超级贝氏体钢Fe-0.40C-2.2Mn-1.5Si为对象,通过热模拟试验、扫描电镜、X射线衍射分析和拉伸试验等方法,研究等温转变温度和保温时间对试验钢的贝氏体相变、微观组织和力学性能的影响。结果表明,随着等温转变温度的降低,钢的显微组织中贝氏体形貌从颗粒状贝氏体转变为板条状贝氏体,其强度逐渐提高,但伸长率和强塑积先增大后减小;随着保温时间的增加,钢的抗拉强度逐渐降低,而伸长率和强塑积逐渐增大,因此可通过适当延长相变时间来改善钢的综合力学性能;在350℃下保温90min时,试验钢显微组织中残余奥氏体体积分数最大,且具有最大强塑积。
The effects of isothermal temperature and holding time on bainitic transformation, microstructure and properties of a super bainitic steel Fe-0.40C-2.2Mn-1.5Si were studied by thermal simulating test, SEM, XRD and tensile tests. The results show that with the decrease of isothermal temperature, microstructure of the steel changes from granular bainite to lath-like bainite, and its strength gradually improves while its elongation and product of strength and elongation (PSE) first increase and then decrease. In addition, with the extension of isothermal holding time, the tensile strength decreases whereas the elongation and PSE increase. So the comprehensive mechanical properties of the bainitic steel can be improved by prolonging the transformation time properly. The steel sample transformed at 350 °C for 90 min has the maximum volume fraction of retained austenite and the optimum PSE.
