Abstract: The tested H section steel Q235 (/% : 0.06C, 0.30Si, 1.60Mn, 0.010P, 0.003S, 0.025Mo, 0.40Ni, 0.017Ti, 0.15Cu) is produced by 80 t LD-LF-feeding silicon-calcium wire-28 t tundish-430 mm x 300 mm x 85 mm H section CC bloom-hot rolling process. Due to the longitudinal crack easily occurred on surface of H section steel bloom, based on real process parameters of through type double submerged nozzle for H section casting bloom, a mathematical model is established and the calculation of distribution of flow field and temperature field in mold is carried out by using fluid finite element simulation software CFD. It is obtained that with using through type double submerged nozzle the impact depth in pool is large that is unfavorable to inclusions floating off； and the liquid surface can't get enough heat supply led to bloom shell more earlier solidification and unfavorable to slag melting. The results of numerical simulation show that as casting by using modified three side nozzle, the unfavorable factors with using through nozzle are avoided, the distribution of flow field and temperature field is reasonable, and the possibility of bleeding trouble and occurrence of crack decreases.

Key words: Steel Q235, H Section Steel Continuous Casting, Quality Defects, Numerical Simulation, Submerged Nozzle, Structure Optimization

摘要： 研究的H型钢Q235(/%:0.06c，0.30si，1.60Mn，0.010P，0.003S，0.025Mo，0.40Ni，0.017Ti，0.15Cu)由80 t LD-LF-喂硅钙线-28 t中间包-430 mm×300 mm×85 mm H型连铸一热轧工艺生产。由于H型铸坯易产生纵裂纹缺陷,根据H型连铸坯采用直通型浸入式双水口浇铸的实际工艺参数建立数学模型,采用流体有限元软件CFD进行结晶器流场和温度场分布汁算,得出直通型双水口浇铸时,熔池冲击深度大,不利夹杂上浮;液面得不到足够热量补充,导致坯壳过早凝固,不利于化渣。数值模拟结果表明,改用三侧孔水口进行浇铸,避免了直通型水口的不利因素,流场和温度场分布合理,可降低漏钢事故和裂纹发生的机率。

关键词: Q235钢, H型连铸坯, 质量缺陷, 数值模拟, 浸入式水口, 结构优化