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<p>The GH4706 high-temperature nickel-based alloy has received widespread attention in aerospace, nuclear energy, petrochemicals, and other industries due to its exceptional mechanical properties and low cost. However, ingot defects occur during secondary refining via electroslag remelting process because of the insufficient technical maturity. A two-dimensional transient multi-physics model of the ESR process for GH4706 and a freckle prediction model are established based on the density inversion theory. The effects of current and melting rate on the macrosegregation of the key element titanium and on the freckle formation prediction are investigated. The results indicate that reducing the remelting current and melting rate appropriately can decrease the depth of the molten pool and stabilize the solidification front, thereby improving the solidification behavior of the ingot. Freckles are more likely to form in the region from the central axis to half the radius of ingots. The molten pool depth and the Rayleigh number increase, the maximum Rayleigh number shifts closer to the central axis, and the freckle defect worsens as the current and melting rate increase. The maximum positive segregation index rises from 0.36 to 0.542 as the remelting current increases from 2000 to 4000 A. The maximum positive segregation index increases from 0.39 to 0.578 as the melting rate increases from 0.5 to 1.1 kg/min. Appropriately reducing the remelting current and melting rate can effectively suppress freckle formation.</p>

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Mathematical and Numerical Predictions of Multi-physics Field and Freckle Formation Prediction During Electroslag Remelting Process

  • 期刊论文

  • 发表日期：

    2026年7月14日

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  • Fang Wang,
  • Chongming Ma,
  • Zhongqiu Liu,
  • Xuechi Huang,
  • Baokuan Li

摘要

The GH4706 high-temperature nickel-based alloy has received widespread attention in aerospace, nuclear energy, petrochemicals, and other industries due to its exceptional mechanical properties and low cost. However, ingot defects occur during secondary refining via electroslag remelting process because of the insufficient technical maturity. A two-dimensional transient multi-physics model of the ESR process for GH4706 and a freckle prediction model are established based on the density inversion theory. The effects of current and melting rate on the macrosegregation of the key element titanium and on the freckle formation prediction are investigated. The results indicate that reducing the remelting current and melting rate appropriately can decrease the depth of the molten pool and stabilize the solidification front, thereby improving the solidification behavior of the ingot. Freckles are more likely to form in the region from the central axis to half the radius of ingots. The molten pool depth and the Rayleigh number increase, the maximum Rayleigh number shifts closer to the central axis, and the freckle defect worsens as the current and melting rate increase. The maximum positive segregation index rises from 0.36 to 0.542 as the remelting current increases from 2000 to 4000 A. The maximum positive segregation index increases from 0.39 to 0.578 as the melting rate increases from 0.5 to 1.1 kg/min. Appropriately reducing the remelting current and melting rate can effectively suppress freckle formation.