Q235小方坯连铸过程中凝固特性的研究

Research on solidification of Q235 billet in continuous casting process

分析了Q235凝固时的结晶特性,柱状晶容易生长.数值计算了小方坯连铸机在2.6 m/min拉速、不同二冷配水下铸坯的温度场和凝固前沿温度梯度.在弱水冷却时,铸坯坯壳凝固前沿温度梯度比较小,得到细小的柱状晶和少量等轴晶.连铸坯中间裂纹主要与二冷水相关,合适的二冷配水可降低或消除中间裂纹.

The crystal characteristic in Q235 solidifying was analysed and it is found that the eolummar crystals develop easily. Billet temperature field and temperature gradient in the front of solidifying shell were computed under the condition of 2.5 m/min casting speed for different secondary water strategy. Temperature gradient is rather small at the head of shell during soft water cooling; the thinner columnar crystals and a small amount of the equiaxed grain ean be obtained. Midway eraek is severely influenced by the seeondary cooling water and the suitable soft rate of the soft secondary cooling water can either reduce or eliminate the midwav crack.