Manufacturing Processes of Titanium Alloy Bars

The production of titanium alloy bars covers raw material preparation, primary hot working, secondary cold working, surface finishing, heat treatment and final inspection. Titanium features high activity at high temperature, so the whole process requires strict temperature control and anti-oxidation measures. Below is a full elaboration on each procedure.

Titanium alloy raw materials start from vacuum arc remelting (VAR) or electron beam melting to produce qualified titanium ingots, which effectively reduce impurities and gas content (oxygen, hydrogen, nitrogen).

• The ingot is cut into fixed-length cylindrical billets according to production specifications.
• Surface scaling, cracks and inclusions on billets are removed by sawing, grinding and peeling to avoid defects spreading during subsequent forming.
• Pre-inspection: Chemical composition, macrostructure and surface quality testing are carried out to ensure raw material compliance.

Billets are heated in a dedicated heating furnace.

• Heating temperature: Controlled between 850℃ ~ 1150℃, varying with different titanium grades.
• Protection: High-temperature anti-oxidation coating or inert gas protection is adopted to prevent titanium from reacting with oxygen and nitrogen in the air to form brittle oxide layers and gas embrittlement.
• Heating uniformity: Slow heating is required to avoid internal thermal stress and cracking of the billet.

Hot working is the main procedure for bulk forming of titanium alloy bars, including hot rolling, hot forging and hot extrusion. It improves microstructure and mechanical properties through plastic deformation at high temperature.

Heated billet → Multi-pass continuous rolling by rolling mill → Intermediate cooling → Multi-group rolling finishing → Semi-finished rolled bar

1. High production efficiency, suitable for mass production, low comprehensive cost among all hot working methods.
2. Large adjustable size range: conventional diameter 8 mm ~ 120 mm, mainly round bars. Square bars and flat bars can also be produced via special rolls.
3. Deformation is relatively uniform, but the surface has thin oxide scale and slight rolling lines, so the surface finish is moderate.

Conventional industrial titanium bars, general mechanical structural parts, chemical pipeline accessories, and ordinary corrosion-resistant components with no strict requirements on surface precision.

Divided into hammer forging and press forging, including open die forging and closed die forging.

Heated billet → Repeated upsetting & stretching by forging equipment → Forming to target diameter → Air cooling or slow cooling

1. Severe plastic deformation during forging, which fully refines grain structure, eliminates casting defects such as porosity and shrinkage cavity, and greatly improves material compactness, strength and toughness.
2. Excellent performance for large-specification bars: available diameter up to 200 mm and above, the preferred process for large-diameter high-strength bars.
3. Flexible production, suitable for small-batch and customized specifications.
4. Compared with rolling, production efficiency is lower and cost is higher.

Aerospace bearing structural parts, high-load mechanical components, thick-diameter titanium bars for pressure vessels, and key parts requiring high comprehensive mechanical properties.

Uniformly heated billet → Put into extrusion cylinder → Pushed by extrusion ram → Pass through fixed extrusion die → Continuous extruded bar

1. Three-dimensional compressive stress during extrusion, the metal has good fluidity, and the internal microstructure is extremely uniform with stable performance.
2. High dimensional accuracy and smooth original surface; the oxide layer is thin and easy to remove.
3. Main applicable diameter: 15 mm ~ 80 mm, mostly used for medium and small diameter bars, and can also produce special-shaped bars.
4. The process is stable, and the material streamline is continuous, with outstanding fatigue resistance.

High-precision bar blanks, titanium tube billets, aerospace hydraulic system parts, and semi-finished products for deep cold working.

Cold working is carried out at room temperature based on hot-worked semi-finished bars, mainly including cold drawing and cold rolling. No high-temperature oxidation occurs, focusing on improving dimensional tolerance, surface quality and surface hardness.

Hot-worked bar → Pickling & descaling → Surface lubrication → Multi-pass drawing through hard alloy dies → Straightening → Semi-finished cold-drawn bar

1. Ultra-high dimensional precision, strict diameter tolerance, excellent straightness.
2. Mirror-like smooth surface, no obvious lines or pits; surface roughness is far better than hot-worked products.
3. Cold work hardening effect: the surface strength and hardness are increased, while the ductility is slightly reduced.
4. Main applicable size: 8 mm ~ 20 mm small-diameter bars.

Precision machinery parts, standard fasteners, medical implant blanks, instrument parts and other products with strict requirements on size and surface.

Similar to cold drawing in principle, adopting roller group for rolling forming.

• Features: More uniform cross-section deformation, better roundness, suitable for thin and small bars.
• Matching use: Often combined with cold drawing to further optimize surface and size.

Note: Before cold working, hot-worked bars must undergo pickling & descaling (mixed acid solution cleaning) to completely remove high-temperature oxide scale, otherwise the die will be worn and the surface will be scratched.

After forming, a series of finishing treatments are conducted to meet different industry standards and customer requirements.

Hot-forged and hot-rolled bars with thick surface oxide layers or defects are processed by lathe turning.

• Function: Remove surface defects, oxide layers and decarburized layers, achieve precise outer diameter and smooth surface.
• Grade orientation: Widely used for aerospace-grade and medical-grade titanium bars with high quality requirements.

Secondary surface treatment after turning or cold working, including rough polishing and fine polishing.

• Effect: Surface roughness Ra ≤ 1.6 μm or even lower, achieving high-gloss surface.
• Application: Medical implanted bars, food-grade equipment parts, high-end electronic components.

Bars will produce slight bending deformation during hot rolling, forging, drawing and cooling.

• Equipment: Multi-roller straightening machine or hydraulic straightening press.
• Purpose: Ensure the overall straightness of the bar, which is a necessary procedure for finished products.

Cut the long continuous bars into fixed lengths according to orders, and remove burrs at the ends by grinding to ensure neat end faces.

Heat treatment is used to adjust microstructure, optimize mechanical properties and eliminate residual stress, which is an essential link for titanium alloy bars. Common types are as follows:

• Process: Heat to 600℃ ~ 800℃, hold temperature and then cool slowly.
• Function: Eliminate residual stress generated during hot/cold working, restore material ductility and machinability, stabilize microstructure.
• Applicable: All pure titanium, α titanium alloys and general α+β titanium alloys.

• Process: High-temperature solution treatment followed by low-temperature aging strengthening.
• Function: Significantly improve tensile strength, yield strength and hardness.
• Applicable: Heat-treatable reinforced α+β titanium alloys (such as TC4) and β titanium alloys, mostly used for high-strength aerospace parts.

Low-temperature short-time heat treatment, specially for cold-worked bars, to eliminate cold working stress while retaining cold work hardening effect.

All finished bars must pass full inspection before delivery:

1. Dimensional inspection: Diameter, length, straightness, roundness.
2. Surface inspection: No cracks, scratches, inclusions and other defects.
3. Performance inspection: Mechanical properties, metallographic structure, hardness test.
4. Non-destructive testing: Ultrasonic testing, eddy current testing to detect internal tiny defects.
5. Packaging: Moisture-proof and anti-collision packaging, mark grade, specification, heat treatment state, batch number and standards.

Titanium Alloy Ingot → Cutting into Billets → Surface Cleaning & Inspection → High-temperature Protected Heating
→ Primary Hot Working (Hot Rolling / Hot Forging / Hot Extrusion) → Cooling → Pickling & Descaling
→ Secondary Cold Working (Cold Drawing / Cold Rolling, optional) → Heat Treatment (Annealing / STA)
→ Straightening → Fixed-length Cutting → Turning / Polishing (optional) → End Deburring
→ Full Quality Inspection → Labeling & Packaging → Finished Products

We support customized production of various grades and specifications of titanium alloy bars, including ASTM/UNS standard grades such as UNS R56320 Gr9, TC4 Gr5, pure titanium Gr1/Gr2. We can customize processing technology, precision tolerance and surface treatment according to your actual usage scenarios, industry standards and drawing requirements, with complete quality inspection reports and stable supply. Feel free to contact us for technical parameters, quotation and sample support.

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