The industrial production of titanium and titanium alloys, whether it is remelted consumable electrodes, forged billets, or shaped castings, is mostly obtained through vacuum consumable electrode arc melting. With the development and progress of modern technology, the melting of titanium and titanium alloys, including vacuum consumable electrode arc melting, has successively developed some new advanced technologies. Representative technologies in recent years are as follows:
1. Method for preparing electrodes for vacuum consumable melting of titanium alloys with direct addition of high melting point metals
On the basis of the conventional preparation of electrodes for titanium alloy vacuum consumable arc melting, the method of welding electrodes composed of directly pressed electrode blocks with certain grooves and high melting point metal rods suitable for the groove shape of the electrode blocks can produce high-quality ingots with uniform composition that meet the ratio calculation requirements by selecting appropriate vacuum consumable arc melting processes.
2. The process of resuming arc after interruption of electricity in the vacuum consumable melting process of titanium and titanium alloys
The process of vacuum consumable melting of titanium and titanium alloys involves the following steps: when the melting process is interrupted and the arc is restarted, the melting current is quickly increased to 75% -80% of the normal melting current, while maintaining the current; After the edge of the molten pool reaches the crucible wall, hold for 2-3 minutes, and then quickly increase the melting current to normal melting current. The advantage of this process is that it significantly shortens the total arc starting time, reduces the gap between the cooling volume of the ingot and the crucible wall after shrinkage, and avoids internal shrinkage formed by the cooling and solidification of the ingot. When the melting current reaches 75-80% of the normal melting current, the melting current is maintained for a period of time, which can accurately control the melting speed of the electrode and the solidified molten pool, Avoid the instantaneous generation of a large amount of molten liquid flowing into the gap between the ingot and the crucible wall, or causing cold shut defects.
3. Melting and recovery method of pure titanium block waste
The smelting and recovery method for pure titanium block waste involves using an electron beam cooling bed furnace with six electron guns, loading selected ingredients into the feeder of the electron beam cooling bed furnace for smelting, and then cooling the resulting ingot out of the furnace to obtain the finished product. This method directly uses TA1 recycled material for melting, avoiding waste crushing, electrode block pressing, and electrode welding. Single ingot smelting can melt 9 bar materials with a total weight of about 6.5 tons per day using a single equipment, while double ingot smelting can melt 18 bar materials with a total weight of about 13 tons per day using a single equipment, greatly improving recovery efficiency and speed.
4. Electron beam cold bed melting recovery method for titanium and titanium alloy scrap
The electron beam cold bed melting recovery method for titanium and titanium alloy scrap materials involves weighing pure titanium scrap materials based on the composition of the melted titanium and titanium alloy, or one or two mixtures of pure titanium scrap materials and titanium alloy scrap materials mixed with sponge titanium and pure alloy added elements and/or intermediate alloys. The amount of pure titanium and titanium alloy scrap materials added in the mixture is 10% to 90% by mass percentage; Then, it is pressed into electrode blocks, and the electrode blocks are subjected to an electron beam cold bed melting furnace to obtain titanium or titanium alloy ingots. This method can use up to 100% pure titanium scrap to produce qualified pure titanium ingots, or use up to 90% titanium and titanium alloy scrap to produce qualified titanium alloy ingots; Only one electron beam cooling bed melting is required, no second or third melting is required.
5. Melting method for clean titanium and titanium alloy ingots
The melting method for clean titanium and titanium alloy ingots is as follows: weigh sponge titanium or pure alloy with added elements, intermediate alloy, and sponge titanium, press sponge titanium or mixed pure alloy with added elements, intermediate alloy, and sponge titanium into electrode blocks, weld the pressed electrode blocks into electrodes, and use an electron beam cooling bed furnace to perform one electron beam cooling bed melting of the electrodes to obtain clean Titanium or titanium alloy ingots with uniform chemical composition; The vacuum degree of electron beam cold bed melting is lower than 6 × 10-2Pa, melting speed of 70-150kg/h, melting power of 100-300kw; The addition of pure alloy elements and intermediate alloys accounts for 0-20% of the total weight of titanium alloy ingots. The produced titanium and titanium alloy ingots have uniform chemical composition, better macroscopic structure than vacuum consumable arc melting ingots, and are free of high melting point inclusions such as TiN and WC.
6. Melting method of titanium alloys containing high melting point alloying elements
Industrialized preparation method for titanium alloy ingots containing high melting point alloying elements. By selecting the raw materials of the alloy, using specially assembled electrode blocks, and using conventional vacuum consumable arc melting technology, adjusting the current and voltage of the three melting processes, a titanium alloy ingot with uniform chemical composition and no inclusions containing high melting point alloy elements is prepared. High melting point metals are evenly distributed in the consumable electrode, making the preparation of consumable electrodes convenient and cost-effective. The current and voltage parameters during melting are reasonable. Based on the traditional process route, low-cost pure metal plates are used according to specific consumable electrode assembly methods to replace the addition of expensive intermediate alloys and other pure metals to titanium alloys, Using multiple vacuum consumable arc melting furnaces to obtain titanium alloy ingots with uniform composition and high melting point alloy elements, suitable for industrial applications.
