Vacuum heat treatment of Ti6Al4V

Ti-6Al-4V (also known as Ti64 or Grade 5 titanium) is an α-β two-phase titanium alloy with extremely high chemical reactivity. At high temperatures, it readily absorbs oxygen, nitrogen, and hydrogen, causing surface contamination, hydrogen embrittlement, and decreased plasticity. Annealing must be performed in a high-vacuum environment; nitrogen cooling is not permitted, and only high-purity argon is allowed.

I. Why Use SIMUWU Vacuum Annealing Furnaces for Ti64?

1. High-vacuum sealed chamber, eliminating surface oxidation and oxygen-rich α-layer: The high-vacuum annealing furnace maintains a stable working vacuum ≤ 5×10⁻³ Pa, suppressing oxygen and nitrogen absorption by the titanium alloy. The annealed workpiece is bright and free of oxidation color, eliminating the need for subsequent sandblasting and pickling; meeting the surface quality requirements of aerospace, medical, and chemical titanium parts.

2. Precise zoned temperature control, excellent furnace temperature uniformity: Full-furnace radiant heating, with temperature deviation controllable within ±5℃, avoids localized overheating and grain coarsening, ensuring uniform microstructure and mechanical properties of the Ti64 throughout the furnace.

3. Effective vacuum dehydrogenation, eliminating the risk of hydrogen embrittlement: Hydrogen is extracted from the material under vacuum and high-temperature conditions, keeping the hydrogen content within safe limits and addressing the issue of hydrogen embrittlement and fracture in forged and welded Ti64.

4. Controllable cooling system, supporting vacuum furnace cooling/forced high-purity argon cooling: Utilizes 99.999% high-purity argon for cooling; nitrogen is strictly prohibited. The cooling rate can be matched to product requirements, and the α/β phase ratio can be stably controlled.

5. Adaptable to various workpiece shapes: Can process in batches of bars, plates, forgings, machined parts, welded assemblies, and additively manufactured Ti64.

II. Vacuum Heat Treatment Process

1. 1. Eliminate processing stress, homogenize microstructure, improve plasticity, and obtain stable comprehensive mechanical properties.
2. 2. Vacuum degree: ≤5×10⁻³ Pa during the isothermal stage
3. 3. Heating: Room temperature → 760~780℃, heating rate 3~8℃/min (reduce rate for thick and large parts to prevent deformation)
4. 4. Holding: 760~780℃, holding time according to wall thickness: <10mm: 60~90min; 10~30mm: 90~150min; >30mm: extend appropriately
5. 5. Two cooling methods are available:
   ① Slow cooling (for low-deformation precision parts): Vacuum furnace cooling to below 300℃, then remove from furnace;
   ② Rapid cooling (for efficiency): After holding, use high-purity argon circulating gas to cool to below 250℃ before removing from furnace.

The following are the specific technical parameters of the SIMUWU high-vacuum titanium alloy annealing furnace RVA-8812:

Should you have any technical questions or requests, please feel free to contact kevin.liu@vacfurnace.com at any time; we are dedicated to serving you.