微合金化钢连铸坯角部横裂纹形成机制  

Formation Mechanism of Transverse Corner Crack on Micro-Alloyed Steel Slab

作　　者：王明林[1] 杨春政[2] 陶红标[1] 张慧[1] 刘建华[2] 吴夜明[1] 

机构地区：[1]钢铁研究总院连铸技术国家工程研究中心,北京100081 [2]首钢京唐钢铁联合有限责任公司,河北唐山063200

出　　处：《钢铁》2012年第10期27-33,39,共8页Iron and Steel

基　　金：国家科技支撑计划资助项目(2006BAE03A04)

摘　　要：为研究微合金钢连铸坯角部横裂纹缺陷形成机制问题,从理论上研究了连铸过程第二相粒子的析出行为,并在板坯连铸生产中进行"卧坯"试验。研究结果表明:X65管线钢中碳氮化钛、碳氮化铌、氮化铝的开始析出温度分别为1 508、1 123、1 165℃,析出峰值温度分别为1 360、870和840℃;"卧坯"试验发现结晶器内及垂直段无裂纹,在距弯月面3 270mm处,即对应于弯曲开始后710mm开始出现多处外弧横裂纹,而弧形段内无内弧裂纹,在弯曲段铸坯角部温度处于钢的第Ⅲ脆性区,同时外弧受拉应力,这是造成外弧角横裂产生的主要原因。In order to research the formation mechanism of transverse corner crack on micro-alloyed steel slab, the precipitation behaviors of the second phase particles during the continuous casting process were investigated, and the industrial trial of stagnant slab were carried out. The calculation results show that the beginning precipitation temperature of titanium carbonitride, niobium carbonitride, aluminum nitride in X65 pipeline steel are 1508, 1123, 1 165 ℃ respectively. And the precipitation peak temperatures are 1 360, 870, 840 ℃. Results of stagnant slab test show that no crack appeared in mold and vertical segments. But at 3 270 mm away from the meniscus, that is 710 mm after bending, transverse crack begins to appear at outer arc surface. No crack in inner arc surface appears. The slab corner temperature at bending part is in the steel brittle temperature zone and under the tensile stress at the same time, which is the main cause for the appearance of transverse corner crack at outer arc surface.

关 键 词：板坯 角横裂 第二相析出 高温延展性 

分 类 号：TF777[冶金工程—钢铁冶金]