高强韧抗震建筑钢Q550GJ的工艺与断裂机理研究

发布时间：2018-04-25 10:55

  本文选题：高强韧抗震建筑钢 + CCT曲线　； 参考：《武汉科技大学》2016年硕士论文

【摘要】：本文研究了Q550GJ高强韧抗震建筑钢,采用低碳并添加了适量的Mo、Cr,Ni合金元素和Nb、Ti微合金元素设计,通过TMCP工艺得到贝氏体+铁素体的双相组织,获得高的强度、良好的韧性和较低的屈强比。通过Gleeble-1500热模拟试验,力学性能试验,OM和SEM组织观察以及CT观察孔洞萌生生长试验,得到如下重要结果:Q550GJ的CCT曲线表明,当冷却速度介于0.1~5℃/S时得到铁素体、珠光体和贝氏体,当冷却速度介于5~50℃/S时得到铁素体,贝氏体和马氏体,为控轧控冷工艺提供有效的依据。控冷工艺的开冷和终冷温度对试验钢组织和屈强比有重要影响:开冷温度越低,铁素体量越多,贝氏体量越少,降低强度和屈强比;终冷温度越低,贝氏体组织细化,M/A岛量有所增加,提高强度和屈强比。采用适当的开冷温度和终冷温度配合工艺,可以获得高强韧和较低屈强比性能的抗震建筑钢。CT观察孔洞萌生生长试验探明了Q550GJ高强韧建筑钢的韧性断裂机制为裂纹和夹杂物导致的单个大孔洞逐步缓慢连接,最后与大量M/A岛导致的小孔洞汇合连接而发的生韧性断裂。
[Abstract]:In this paper, Q550GJ high strength and toughness aseismic building steel is studied. The design of low carbon and appropriate amount of Mo-Cr-Ni alloy element and Nb-Ti microalloyed element is used. The bainitic ferrite dual phase structure is obtained by TMCP process, and the high strength is obtained. Good toughness and low yield ratio. By means of Gleeble-1500 thermal simulation test, mechanical properties test, OM and SEM microstructure observation and CT observation, the following important results are obtained: 1: Q550GJ CCT curve shows that ferrite, pearlite and bainite can be obtained when cooling rate is between 0.1 鈩，

本文编号：1801019