Q690低碳微合金钢热变形微观组织演变及加工图  

Microstructure Evolution and Processing Map of Thermal Deformation of Q690 Low Carbon Microalloyed Steel

作　　者：向嵩[1,2] 谭智林[1,2] 

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025 [2]贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《湖南大学学报（自然科学版）》2013年第4期80-86,共7页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(50901022)

摘　　要：利用Gleeble-3800数字控制热/力模拟试验机研究了Q690低碳微合金钢在变形温度850～1150℃,应变速率0.01～30s-1条件下的高温单道次压缩变形行为.建立了基于动态材料模型(DMM)的加工图,结合OM观察变形体微观组织确定了该钢种的高温热变形机制.结果表明:应变量0.7及以下的加工图中包含2个峰区(1 000～1 120℃,0.01～0.37s-1和1 100～1 150℃,3.16～30s-1)和3个加工失稳区(850～900℃,0.01～0.32s-1和850～900℃,10～30s-1以及1 000～1 085℃,1～30s-1).应变量超过0.8的加工图包含2个峰区(1 025～1 100℃,0.01～0.38s-1和1 100～1 150℃,3～30s-1),失稳区为低温(850～900℃,0.01～30s-1)以及应变速率1s-1以上的中低温度(850～1 100℃)范围,在这两个峰区峰值点附近的热变形显微组织为均匀的完全动态再结晶组织,因此,这两个区域均适合Q690钢的热加工变形.The hot deformation behavior of Q690 low carbon microalloyed steel was studied with compression tests on a Gleeble-3 800 simulator in the temperature range from 850 ℃ to 1150 ℃ and true strain rate from 0.01 s-1 to 30 s-1.Based on dynamic materials model（DMM）,the processing map for the Q690 steel was obtained,and the microstructure characteristics were studied with optical microscope.The results have shown that,when the true strain is less than 0.7,there are two efficiency dissipative peak regions（1 000～1 120 ℃,0.01～0.37s-1 and 1 100～1 150 ℃,3.16～30 s-1） and three processing instability regions（850～900 ℃,0.01～0.32s-1 and 850～900 ℃,10～30s-1 and 1 000～1 085 ℃,1～30s-1） in the processing maps.The true strain is more than 0.8,there are two efficiency dissipative peak regions（1 025～1 100℃,0.01～0.38 s-1 and 1 100～1 150 ℃,3～30 s-1）,and the flow instability regions appear at the temperature of 850～900 ℃ and the strain of 0.01～30 s-1,as well as at the temperature of 850～1 100 ℃ and the strain rate of 1～30 s-1.The microstructures of the two peak efficiency regions are uniform,fully dynamic recrystallization grain,so the optimum processing parameters of hot deformation have been achieved.

关 键 词：低碳微合金钢 热变形 动态再结晶 加工图 

分 类 号：TG111.7[金属学及工艺—物理冶金]