Application of TIG Welding in Shipbuilding Industry

Technical Advantages of TIG welding

Fundamental Principles
TIG welding utilizes inert gases (argon or helium) as shielding media. Its core mechanism involves generating a high-temperature arc between a non-consumable tungsten electrode and workpiece to melt base metal and filler material, while the argon shield prevents atmospheric contamination. This method proves particularly effective for non-ferrous metals and alloys including stainless steel, aluminum, copper, and titanium.

Technical Superiority
• Precision Control: Low heat input enables aesthetic weld profiles, suitable for thin plates (0.5-6mm) and complex structures.
• Slag-free Operation: Shielding gas eliminates oxygen/nitrogen intrusion, minimizing defects like porosity and cracks.
• Material Versatility: Capable of welding high-demand materials such as stainless steel, aluminum alloys (especially 5083 aluminum alloy commonly used in ships), and titanium alloys.
• Full-position Welding Capability: Adaptable to confined spaces and challenging positions (vertical/overhead) in hull construction.

Key Applications in Shipbuilding

Thin-plate Hull Welding
Modern vessels extensively employ thin steel plates (4-8mm) and aluminum alloys to reduce weight and enhance fuel efficiency. Compared to conventional methods prone to plate distortion, TIG welding's low heat input significantly minimizes Heat-Affected Zone (HAZ) and prevents warpage.

Seam Welding for Piping Systems & Pressure Vessels
Critical components like fuel lines, hydraulic piping, and LNG fuel tanks demand exceptional sealing integrity and corrosion resistance. TIG welding achieves backside fusion without internal oxidation through single-side welding techniques. Pulsed TIG welding, with its controlled current pulsation for molten pool management, proves particularly effective for duplex stainless steel piping in all-position welding.

Dissimilar Metal Welding for Critical Structures
Components such as rudder shafts and propeller brackets require joining stainless steel with carbon steel. Conventional methods risk brittle phase formation. TIG welding enables high-strength dissimilar metal joints through precise penetration control and interpass temperature management using ER309L filler wires. The combined process of TIG root pass with submerged arc welding for cover layers can increase service life by approximately 30%.

Propeller Repair Welding
As the primary propulsion component of ocean-going vessels, propellers directly determine ship performance. Subjected to tremendous torque and marine corrosion, propeller materials (typically manganese brass or aluminum bronze) must exhibit superior mechanical properties and corrosion resistance. However, casting defects and selective leaching (zinc in brass/aluminum in bronze) often degrade material performance, leading to corrosion fatigue cracks or stress corrosion cracking. Current repair protocols for large marine propellers predominantly employ TIG welding for crack remediation.