1、 Welding materials and equipment for pipe fittings

Welding wire selection: Priority should be given to using ERTi-2 welding wire to ensure compatibility with the base material.

Protective gas: Use argon gas with a purity of ≥ 99.995% and a water content of ≤ 50mg/m ³ to continuously protect the melt pool and high-temperature zone.

Welding method: It is recommended to use manual tungsten inert gas welding to adapt to the low thermal conductivity characteristics of titanium materials.

2、 Preparation before welding

Groove processing:

Use an alumina grinding machine to polish the groove and avoid overheating and discoloration of the base material.

The groove shape should be flat, and the inner and outer surfaces within 50mm range should be polished, polished, and cleaned with acetone.

Cleaning management:

If the groove and welding wire are left for more than 2 hours, they need to be cleaned again or sealed with self-adhesive tape for protection.

Operators should wear clean gloves to prevent oil pollution.

3、 Welding Process Specification

Parameter control:

Using small wire energy welding, low current, slow welding reduces the heat affected zone.

Interlayer temperature ≤ 200 ℃, inhibits grain coarsening.

Argon protection measures:

Large pipe diameter: Personnel inside the pipe wear gas masks and hold protective covers to cover the back of the melt pool.

Small tube diameter or fixed port: overall argon protection, seal the tube with soluble paper at a distance of 150-300mm from the groove, fill with argon and exhaust the air.

Operation details:

It is prohibited to initiate an arc on the surface of the welded component. After extinguishing the arc, the welding wire must be removed under argon protection.

Delay argon filling to below 300 ℃ after arc interruption to prevent oxidation.

4、 Quality Inspection and Defect Control

Weld color analysis: Silver white is qualified, blue or yellow indicates oxidation contamination and needs to be repaired.

Non destructive testing: Penetrant testing is performed on the root weld bead, and X-ray testing is performed on the entire weld seam to ensure no cracks or porosity.

Mechanical performance testing: Evaluate the protective effect through acid washing method, verify the tensile strength and plasticity of the weld seam.

5、 Technological Innovation and Structural Optimization

Composite pipe welding technology: adopting patented design of titanium steel composite pipe to improve welding strength and sealing performance.

Improvement of protective device: The all copper protective cover reduces iron ion pollution and is suitable for all position welding requirements.