Patent ID: 11859262
Assignee: GAONA AERO MATERIAL CO., LTD.
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 2:
3. The smelting process according to claim 1, wherein in the step of VIM, the raw material is melted at a temperature of 1300-1550° C. until melting down, refined under electromagnetic stirring at 1350-1550° C. for 15-120 min, cooled for 1-10 h, and demoulded to obtain a VIM ingot; and the VIM process is performed for a plurality of times to obtain the plurality of consumable VIM ingots;
wherein in the step of VAR for the plurality of times, a first VAR and a second VAR comprise the following steps of: performing the first VAR at a steady-state melting rate of 3.5-7.5 kg/min; initiating helium cooling when 800-2000 kg of the primary consumable electrode is melted; decreasing a current and adjusting the melting rate to 3.0-7.0 kg/min when a weight of the remaining primary consumable electrode is 1500-5000 kg; and starting hot topping when the weight of the remaining primary consumable electrode is 200-1000 kg, thereby obtaining a first VAR ingot;
for the second VAR, first polishing the first VAR ingot, and flattening the first VAR ingot at a head and a tail to obtain a secondary consumable electrode;
performing the second VAR at a steady-state melting rate of 4.0-8.5 kg/min; initiating helium cooling when 1000-3000 kg of the secondary consumable electrode is melted; decreasing the current and adjusting the melting rate to 3.0-7.5 kg/min when a weight of the remaining secondary consumable electrode is 2000-5500 kg; and starting hot topping when the weight of the remaining secondary consumable electrode is 250-1500 kg; and
after the second VAR, vacuum cooling for 1-8 h and then starting stress-relief annealing within 2 h, wherein the temperature is raised to 300-750° C., kept constant for 4-32 h for achieving homogeneous temperature distribution, raised to 800-1000° C. at a rate of 5-50° C./h, kept constant for 4-32 h, lowered to 550-750° C. at a rate of 1-35° C./h, and kept constant for 4-32 h, followed by air cooling.