Influencing Factors and Process Control of Vacuum Consumable Remelting Arc Stability

The behaviors of interelectrode arc during vacuum arc remelting of high-temperature alloy and special stainless steel were investigated in this paper， and the influence factors such as electrode size， external quality， and gas element content on arc stability were analyzed. The results showed that large deviation of electrode diameter significantly affected the calculation of rod base speed， resulting in abnormal adjustment of arc gap， short circuits， and deviation of droplet frequency. The electrode taper should be controlled to be ≤0.5%. Cracks and shrinkage cavities defect on the electrode interfered with arc stability control， especially radial cracks leading to severe instability of droplets and remelting rates. Gas overflow was significant with high nitrogen in base material， which caused arc deviation， fluctuations in droplet and atmosphere pressure. Therefore， it is advisable to control w［N］≤0.003% during electrode preparation. There were obvious differences in equipment among different furnaces， and appropriate PID parameters should be explored.