大扁锭凝固过程模拟及缩孔优化

Solidification simulation and shrinkage optimization of big flat ingots

  • 摘要: 对某钢厂28.7t钢锭凝固过程进行测温,并用有限元方法模拟该钢锭凝固过程温度场和凝固场分布.结果表明:温度模拟值与现场测量值吻合很好,证明模拟具有较高的准确性和可靠性;凝固初期,钢锭底部和保温冒与钢锭模连接处凝固较快;52min时,绝热板与钢锭间已形成一定气隙;前3h,钢锭侧面凝固顺序由模壁向钢锭中心平行推进;凝固后期较凝固前期凝固速度快;热电偶测得,保温冒中心凝固时间为428min,钢锭本体中心顶部凝固时间为365min,冒部全凝时间大于本体全凝时间的15%,有利于控制一次缩孔只存在于冒部.通过模拟将浇注温度由1543℃降低到1533℃,不但不影响保温帽钢液对本体的补缩作用,还可以使缩孔减小6mm,有利于提高钢锭质量.

     

    Abstract: The temperature of a steel ingot of 28.7 t was measured during solidification and the temperature field and solidification process of the steel ingot were simulated by a finite element method. It is shown that the simulated values of the temperature field agree well with the measured data, indicating that this simulation is accurate and reliable. At the initial stage of solidification, the bottom of the steel ingot and the connection zone between the ingot mold and the insulating riser solidify faster. At 52 min, an air gap forms between the steel ingot and the adiabatic plate. At the first 3 h, the steel ingot solidifies parallelly from the mold wall to the center. The later stage of solidification is faster than the early stage. The solidification time is 428 rain in the center of the insulating riser and the final solidification time is 365 min in the center of the ingot body. The former is 15% longer than the later, which is benefit to control shrinkage cavities in the insulating riser only. Based on the simulation, the pouring temperature reduces from 1543℃ to 1533℃, which does not affect steel feeding but also can reduce 6 mm of the depth of shrinkage. This method can improve the quality of steel ingots.

     

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