The corrosion resistance of titanium equipment depends on ensuring welding quality and avoiding weld defects.

Key Considerations in Titanium Welding

1.Core Challenge:

Titanium welding is less about bonding technology and more about contamination prevention.

Strict pre-weld cleaning of grooves and adjacent areas is essential.

2.Inert Gas Shielding:

Use argon gas (purity ≥99.99%) to protect both the front and back sides of the weld and the heat-affected zone.

Without proper shielding, titanium’s high reactivity at elevated temperatures leads to oxygen, nitrogen, hydrogen, or carbon absorption, causing cracks, pores, and other defects.

3.Leak Detection Holes:

For titanium-clad or lined vessels, install leak detection holes to:

Enable argon backside shielding during welding.

Inspect weld integrity post-welding.

Monitor leaks during operation.

Case Studies of Welding-Related Failures

1.Yueyang Petrochemical’s Titanium-Lined Oxidation Tower:

Failure due to lack of leak detection holes, preventing argon backside shielding.

Result: Leakage and corrosion-induced perforation.

2.Shanghai Petrochemical (SPC) PTA Adsorption Tower:

Constructed with Grade 2 titanium-clad plate.

After 7 years of service (2005), titanium circumferential weld cracks at the bottom caused leaks due to welding defects.

3.Baosteel’s Coal Desulfurization High-Pressure Reactor:

A multi-layer rolled plate titanium-lined vessel experienced repeated leaks and perforations.

Root Cause: Weld defects exposed by internal fluid erosion, allowing sulfuric acid and thiocyanic acid to penetrate the titanium-steel interface, triggering galvanic corrosion.

Solution: Implemented groove gouging and repair for critical erosion zones, multi-layer welding for overlapping titanium cover plates, and rigorous non-destructive testing to eliminate defects.

Key Takeaway:

Most titanium equipment failures stem from poor welding quality. Strict adherence to shielding protocols, leak detection design, and post-weld inspection is critical for long-term reliability.