How To Choose Vacuum Melting Equipment For High-End Titanium Alloy Processing?

Titanium features high chemical activity. When melted at high temperatures, it readily reacts with oxygen, nitrogen, hydrogen and carbon to form brittle phases. This degrades the material's ductility and fatigue performance, impairs non-destructive testing results, and restricts the yield and service reliability of  high-end titanium products. Vacuum melting serves as the critical primary process for titanium alloy production. Melting equipment determines ingot purity as well as compositional and microstructural stability, forming the fundamental guarantee for high-end titanium alloy processing.

1. VAR

A mainstream process for aerospace-grade titanium ingots. The consumable electrode is melted by electric arc under vacuum or low-pressure argon atmosphere, and solidified in a water-cooled copper crucible.

Advantages: Effective degassing, high ingot density and favorable non-destructive testing performance; suitable for mass production of large-size round ingots such as Gr5 and TA15.

Disadvantages: Narrow compositional adjustment range, poor capability for special-shaped billets, and difficulties in trace-element control.

2. VIM

Melting is realized via electromagnetic eddy-current heating in ceramic crucibles.

Advantages: Sufficient electromagnetic stirring and uniform composition; applicable to small-batch production of special titanium alloys and master alloys with multiple grades.

Disadvantages: Ceramic crucibles tend to introduce inclusions. It is rarely used for producing finished ingots independently, and mostly serves to prepare master-alloy electrodes for VAR or EB processes.

3. EBCHM

Raw materials are melted by high-energy electron beams. Melt overflows for forming after impurity removal in a water-cooled cold hearth, where impurities can be trapped.

Advantages: Superior impurity-removal capacity. Sponge titanium and recycled scrap can be directly used. Hard-alpha defects and segregation are well controlled. Flat ingots can be manufactured to suit large aerospace thick-plate components.

Disadvantages: High equipment investment and energy consumption, low production speed; not cost-effective for small-batch production.

High-end triple-process route: VIM for master-alloy preparation → EB cold-hearth refining → VAR remelting. Multi-stage purification balances compositional accuracy, inclusion control and microstructural stability, and is adopted for high-end aerospace titanium alloys.

1. Ultimate Vacuum Degree and Pressure Rise Rate

Titanium readily absorbs gas. For high-end furnaces, the ultimate vacuum shall be ≤ 1×10⁻³ Pa. The pressure rise rate reflects cavity sealing performance. Poor sealing causes excessive oxygen and nitrogen content and material embrittlement. Stringent requirements are imposed for medical implants and Class-1 aerospace forgings.

2. Stable Heat-Source Control

The arc-stabilized power supply for VAR and beam-flow control for EB are core technologies. Fluctuations in electric arc or electron beam flow trigger segregation, porosity and shrinkage cavities. High-end equipment supports closed-loop real-time power regulation.

3. Water-Cooling Reliability

Copper crucibles, cold hearths and other components sustain severe thermal shock. Monitoring of flow rate, temperature and pressure difference as well as water-leakage alarm functions are required. Cooling failures not only lead to scrapped ingots but may also induce violent reactions between molten titanium and water, posing extremely high safety risks.

4. Recycled-Material Processing Capacity

Titanium processing generates chips, residual electrodes and other scraps. Equipment equipped with pre-treatment and continuous feeding systems cuts raw-material costs. EB cold-hearth melting delivers optimal adaptability to recycled scraps.

5. On-line Monitoring and Data Traceability

Full-process traceability is mandatory for aerospace titanium materials. High-end equipment automatically stores process data including molten-pool images, temperature, vacuum level and power for quality audit purposes.

6. Degassing and Impurity-Removal Capacity

Excess oxygen, nitrogen, hydrogen, hard-alpha phases and high-melting-point inclusions may trigger fatigue fracture of aerospace components. This constitutes the most critical performance gap between ordinary industrial-grade titanium and high-end aerospace-grade titanium.

1. General-Purpose Industrial-Grade Titanium

Select VAR vacuum arc remelting furnaces with moderate vacuum performance and standard arc-stabilized power supplies, fed with sponge-titanium electrodes. It delivers high throughput at low cost. EB cold-hearth melting is not recommended due to long payback periods.

2. Medical-Implant-Grade Titanium

VAR furnaces are the primary choice, prioritizing well-sealed furnace bodies and high-precision arc-stabilization systems. VIM pre-fabrication of master alloys is an option with sufficient budget. Vacuum performance, furnace cleanliness and batch isolation are critical; impurity control takes precedence over production capacity.

3. High-Purity Aerospace-Grade Titanium

EBCHM or dual-mode EB + VAR remelting is adopted. High-performance electron guns, stable beam-flow control, cold-hearth refining and full-process data traceability are required. Qualified recycled scraps can be admixed. This is the baseline requirement for admission into aerospace supply chains.

4. R&D of New Titanium Alloys and Titanium-Matrix Composites

Combine small-scale VIM vacuum induction furnaces with small-scale VAR remelting furnaces. Flexible batching, electromagnetic stirring and adjustable atmosphere support formula iteration and small-batch trial melting. Note that VIM cannot independently produce high-purity ingots and is only used for master-alloy preparation.

Ruihang supply optimal quality raw materials for your precision components production. If you have any purchasing needs, please feel free to contact us via email: Sam.Rui@bjrh-titanium.com