Q345C宽厚板坯边角部横裂纹的控制  

Q345C CONTROL OF TRANSVERSE CRACKS IN THE CORNERS OF WIDE AND THICK SLABS

作　　者：李杰 张彩东 张瑞忠 刘崇 刘小军 鲁会杰 Li Jie;Zhang Caidong;Zhang Ruizhong;Liu Chong;Liu Xiaojun;Lu Huijie(HBIS Material Technology Research Institute,Shijiazhuang 050023,Hebei;HBIS Group Wusteel Company,Pingdingshan 462500,Henan)

机构地区：[1]河钢材料技术研究院,河北石家庄050023 [2]河钢集团舞钢公司,河南平顶山462500

出　　处：《河北冶金》2023年第7期11-15,共5页Hebei Metallurgy

摘　　要：研究了宽厚板坯边角部横裂纹的形成机理。通过高温拉伸试验得到了Q345C钢第三脆性区间为700~900℃。分析了AlN析出对钢的高温塑性的影响:在氮含量一定的条件下,随着钢中[Al]的增加,AlN的析出总量未变,但是其析出温度升高,恶化了钢的高温塑性。理论计算并研究了连铸主要工艺参数对铸坯边角部温度的影响规律,高拉速、低二冷强度及高过热度有利于铸坯边角部温度的提高。在钢中[N]为40~60 ppm时,[Al]控制在0.030%以内可降低板坯的高温裂纹敏感性;同时将拉速由0.75 m/min提高到0.80 m/min,二冷比水量由0.38 L/kg降低到0.30 L/kg,可提高板坯边角部在弯曲区和矫直区的温度,Q345C钢的边角部横裂纹缺陷率可控制在0.5%内。The formation mechanism of transverse cracks at the corners of wide and thick slabs was studied.Through the high temperature tensile test,the third brittle range of Q345C steel is 700~900°C.The effect of AlN precipitation on the high-temperature plasticity of steel was analyzed:under the condition of certain nitrogen content,with the increase of[Al]in steel,the total amount of AlN precipitation remained unchanged,but the precipitation temperature increased,which deteriorated the high-temperature plasticity of steel.The influence of the main process parameters of continuous casting on the temperature of the corner of the casting billet was calculated and studied,and the high tensile speed,low secondary cooling strength and high superheat were conducive to the increase of the temperature of the corner of the casting billet.When[N]in steel is 40~60 ppm,[Al]control within 0.030%can reduce the high temperature crack sensitivity of the slab;at the same time,the tensile speed is increased from 0.75 m/min to 0.80 m/min,the water volume of secondary cooling ratio is reduced from 0.38 L/kg to 0.30 L/kg,the temperature of the corner of the slab in the bending area and straightening area is increased,and the defect rate of cross cracks in the corners of Q345C steel can be controlled within 0.5%.

关 键 词：宽厚板坯 ALN 高温塑性 边角部 横裂纹 

分 类 号：TG142.1[一般工业技术—材料科学与工程]