钛合金铸锭尾部冶金质量影响因素研究

Influence of start-up arc on metallurgical quality of titanium ingot’s back-end in VAR process

摘要:

本文采用数值模拟方法，通过从熔炼起弧阶段的能量输入（以及散热）的角度分析影响铸锭尾部冶金质量的关键因素，对第三次熔炼的起弧工艺参数进行研究，并通过实验进行了验证。结果表明，电流起弧后随着熔炼的进行，铸锭表面温度逐渐升高，在熔炼至铸锭30mm高度处，表面温度达到最高。通过选择合适时机提升起弧电流大小，加快电流上升速度，可以使熔池表面温度明显上升。Φ720mm规格TC17钛合金第三次熔炼起弧电流增大4kA，1min快速升至大电流，大电流保持时间延长6min，能够实现熔池快速健全，达到稳定熔池时熔炼的金属重量减少约一半，数值模拟和实验结果的一致性吻合良好。

Abstract:

In this paper, the numerical simulation method is used to analyze the key factors affecting the metallurgical quality of the ingot back-end from the perspective of energy input ( and heat dissipation ) at the start-up stage during VAR process. The start up stage process parameters of the third smelting process are studied and verified by experiments. The results show that the surface temperature of the ingot gradually increases with the remelting time during the start-up stage, and the surface temperature reaches the highest at the height of 30 mm ingot. By controling the appropriate time to increase the arc current and accelerate the current rise rate, the surface temperature of the molten pool can be significantly increased. The arc current of Φ720mm TC17 titanium alloy increases by 4kA in the third remelting, and rapidly rises to a large current in 1min, then the holding time of the large current is extended by 6min, which can accelerat to bulid the molten pool, and the weight of the molten metal is reduced by about half. The numerical simulation and experimental results are in good agreement.