冷却速率对耐候钢高温力学性能的影响  

Effect of cooling rate on high temperature mechanical properties of weathering steel

作　　者：陈登福[1,2] 宋立伟[1] 董志华[1] 高兴建[1] 王水根[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400030 [2]重庆大学重庆市冶金工程重点实验室,重庆400030

出　　处：《重庆大学学报（自然科学版）》2011年第11期50-55,共6页Journal of Chongqing University

基　　金：国家自然科学基金资助项目(50774105);高等学校博士点科研基金资助项目(20090191110012)

摘　　要：铸坯高温力学性能是铸坯受力过程中决定裂纹产生的关键因素。在Gleeble热/力模拟实验机上模拟测试1.65,5,10℃/s 3个冷却速率下耐候钢Q450NQR1铸坯高温力学性能。在1 050℃,3个冷却速率下试样都出现奥氏体动态再结晶;在850℃,塑性值都达到最低点,断面收缩率接近23%;随着冷却速率的增大,铸坯易产生裂纹的第III塑性区扩大,且向低温段扩展,塑性凹槽变深;增大冷却速率钢的各种强度降低,但增大到一定程度后强度不再降低;小的冷却速率下,奥氏体晶界上很少析出网状或薄膜状铁素体、微合金的化合物被包裹在基体中,利于提高钢的塑性。High temperature mechanical properties are key factors which affect fracture production during deforming process of continuous casting.High temperature properties of weathering steel Q450NQR1 are tested in 3 cooling rates（1.65,5,10 ℃/s） using Gleeble thermo-mechanical simulator.Specimens appear austenite dynamic recrystallization at 1 050 ℃,and the ductility reaches the lowest point and the reduction of area approaches 23% at 850 ℃ in 3 cooling rates.As the cooling rate increases,the low ductility area where cracks are easy to be produced in slabs is enlarged and extended towards low temperature,and the ductility troughs are deepened.The increase of the cooling rate decreases the tensile stress and yield stress,while when the cooling rate increases to some degree,it doesn＇t affect the stress.The low cooling rate decreases the film or network ferrite producing in austenite grain boundary,and the carbonitride of microalloy is enwrapped in matrix,which is helpful to improve the ductility of steel.

关 键 词：冷却速率 耐候钢 Q450NQR1钢 高温力学性能 

分 类 号：TF777.1[冶金工程—钢铁冶金]