How To Ensure Precision in Titanium Tube Processing?

The processing quality of titanium tubes directly Influences the performance stability and service life of products. It is easy to react with gases such as oxygen, nitrogen, and hydrogen in high-temperature environments because of the strong chemical activity of titanium metal.It can form brittle compounds, which significantly reduce material performance.

 

 

 

(I) Billets Selection and Pretreatment

• Billets Selection

Types: Rolled, extruded, or forged blanks.

Key Inspection Items:

Chemical Composition: Control impurities like oxygen, nitrogen, and hydrogen strictly in order to avoid hydrogen and oxygen embrittlement.

Surface Quality: Inspect for defects like cracks, inclusions, and scratches.

 

• Pretreatment

Surface Cleaning: Remove oxide scale by mechanical grinding or pickling with hydrofluoric acid-nitric acid mixed acid; wipe off oil stains with alcohol or acetone; rinse with clean water and dry after pickling to prevent corrosion caused by residual acid.

 

Stress Relief Annealing: Temperature ranges control and the holding time is adjusted according to the blank size. Air cooling or furnace cooling is adopted to eliminate internal stress from rolling/extrusion and avoid processing deformation.

 

(II) Equipment and Tool Preparation

• Processing Equipment

Select high-precision, high-rigidity CNC lathes, CNC milling machines, and special pipe processing machines with good stability to prevent substandard surface roughness and dimensional accuracy caused by processing vibration.

 

• Processing Tools

Cutting Tools: Use cemented carbide or diamond tools with sharp cutting edges to avoid plastic deformation, surface oxidation, or cracks of materials caused by tool blunting; clean oil stains and iron chips before use.

 

Fixtures/Gauges: Need to be cleaned. The parts in contact with titanium materials shall be made of inert metal materials such as copper and aluminum to prevent iron ion contamination.

 

 

(I) Optimization of Cutting Parameters

Cutting Speed: A core control parameter. Because of the poor thermal conductivity of titanium, excessively high speed will cause high temperature at the cutting edge, accelerating tool wear and surface oxidation of titanium; excessively low speed is prone to cause plastic deformation and work hardening of materials. When processing with cemented carbide tools, the speed is controlled. That shall be adjusted according to the pipe diameter, wall thickness, and tool material.

 

Feed Rate: Should be moderate. Excessively high feed rate may increase cutting force, leading to pipe deformation and poor surface roughness; excessively low feed rate will prolong processing time and aggravate friction between tools and workpieces, causing surface oxidation.

 

Cutting Depth: Reasonably distribute according to the blank allowance. Avoid excessively large single cutting depth. It is recommended to adopt the method of multiple small cutting depths to reduce processing stress and surface damage.

 

(II) Cooling and Lubrication

Core Purpose: Reduce cutting temperature, reduce tool wear, prevent material oxidation, and improve processing surface quality.

 

Requirements for Cooling and Lubricating Agents:

Should have good lubricity, cooling performance, and chemical stability, and not react with titanium materials.

Prioritize the use of cutting oils containing special additives such as sulfurized lard and extreme pressure cutting oil; prohibit the use of coolants containing chlorine and fluorine to avoid corrosion of titanium materials or generation of toxic gases.

 

Usage Specifications: Ensure that the cooling oil fully covers the cutting area and takes away heat in a timely manner; avoid mixing of moisture and impurities into the cooling oil to prevent contamination of the titanium tube surface.

 

(III) Dimensional and Surface Quality Control

Dimensional Accuracy Control

Control the outer diameter, inner diameter, wall thickness, and geometric tolerances strictly, like roundness and straightness.

Inspect with high-precision gauges regularly, like micrometers, internal dial gauges, and projectors during processing.

For the processing of thin-walled titanium tubes, adopt mandrel support and reasonable clamping methods to reduce the impact of clamping force.

 

Surface Quality Control

The surface roughness Ra is 0.8-3.2μm.

No cracks, scratches, depressions, oxide scales, and other defects.

If the roughness does not meet the requirements, polish with soft materials such as wool wheels and polishing cloths combined with special polishing pastes.

 

 

(I) Processing Quality Inspection

Dimensional Inspection

Outer diameter, inner diameter, wall thickness, length, and geometric tolerances , like roundness, straightness, and perpendicularity.

High-precision gauges, like micrometers, internal dial gauges, vernier calipers, projectors, and coordinate measuring machines.

 

Surface Quality Inspection

Visual inspection, magnifying glass inspection, or surface roughness tester inspection.

The surface roughness meets the requirements, and there shall be no cracks, scratches, depressions, oxide scales, or other defects.

 

We are specialized in R&D, production and sales of titanium and titanium alloy products including bars,plates,tubes,profile and forgings. For more details,please contact us via the email: Sam.Rui@bjrh-titanium.com.