Q355系列及低合金高强度钢板坯凝固特征及其对中板探伤缺陷的影响与工艺改进  

Feature of Slab Solidification and Its Effect on Ultrasonic Inspection Defect of Medium Plate of Q355 Series and HSLA Steel and Process Improvement

作　　者：颜慧成 范佳 张凯 冯俊鹏 巩彦坤 Yan Huicheng;Fan Jia;Zhang Kai;Feng Junpeng;Gong Yankun(Technological Center,Hansteel Company HBIS Group,Handan,056015;The 3rd Steel Plant,Hansteel Company HBIS Group,Handan,056015)

机构地区：[1]河北钢铁集团邯钢公司技术中心 [2]河北钢铁集团邯钢公司第三炼钢厂,邯郸056015

出　　处：《特殊钢》2021年第6期58-60,共3页Special Steel

摘　　要：通过对Q355系钢中板探伤缺陷进行取样分析,结合板坯连铸凝固传热计算,揭示了板坯凝固末端呈现双锥形液芯的凝固特性,双液芯区域由于C、Mn与H富集,成为中板两侧探伤缺陷的根源。通过工艺改进并严格控制,RH真空脱气时间≥20 min,连铸全程保护,结晶器钢液H含量≤2×10^(-6);连铸过热度≤30℃,板坯中心碳偏析优于1.0级;结合执行板坯、中板缓冷处理,中板探伤正品率达到99.6%。With sampling analysis on defects of Q355 series steel medium plate defect by ultrasonic inspection and heat-transferring simulation for slab solidification process,it is disclosed that the biconical liquid core appearing at slab solidifying front and C/Mn/H gathering in this zone are the cause of the medium plate two side ultrasonic inspection defect.Through process improvement and strict control,the RH vacuum degassing time≥20 min,the whole process of continuous casting protecting,and hydrogen content of steel in mold≤2×10^(-6)and superheat of continuous casting less than 30℃,the center carbon segregation of slab is better than 1.0 rating,combining slow cooling of slab and medium plate,the qualification rate of medium plate inspection is 99.6%.

关 键 词：Q355系钢 末端凝固 探伤缺陷 中板 

分 类 号：TG142.1[一般工业技术—材料科学与工程]