In modern shipbuilding, offshore engineering, rail transit, industrial modules, and lightweight structural manufacturing, the demand for welded aluminum panels continues to rise. These applications require materials with high strength, excellent toughness, superior corrosion resistance, stable deformation behavior at low temperatures, high production efficiency, and consistent quality.

As one of the most advanced solid-state joining technologies available today, Friction Stir Welding (FSW) is rapidly becoming the preferred solution for manufacturing high-performance welded panels.

What Are Friction Stir Welded (FSW) Panels?

1.Basic Principle of FSW

Friction stir welding (FSW) is a solid-state welding technique: a rotating tool (welding head) is pressed between two aluminum alloy plates, and the metal is softened (but not melted) under pressure and frictional heat. Then, through stirring and pressing by the tool, the two metals are mixed at the joint to form a high-strength bond. The entire process requires no filler, produces no molten pool, and generates no spatter or welding fumes.

2.Definition of FSW Panels (Stiffened / Welded Panels)

The term "FSW panel" generally refers to a composite panel formed by welding multiple extruded profiles (aluminum alloy ribs) and panel sheets together using FSW welding, creating a "panel + rib stiffener" structure. This structure combines lightweight, high rigidity, and integrity, making it ideal for ship hulls, decks, bulkheads, modular wall panels, etc.

3. DNV-GL Certification

DNV-GL is an internationally renowned classification society whose certification standards cover ship materials, welding processes, and structural safety. DNV-GL-certified FSW panels mean that they can be directly applied to ship structures that comply with international classification codes, including critical components such as the hull, decks, bulkheads, and structural modules, ensuring the safety and reliability of the vessel in the marine environment.

4. FSW Panel Materials

Marine applications typically require aluminum alloys with excellent seawater corrosion resistance and high strength. Common alloys include:

• 5000 series: 5083, 5086 (preferred for marine environments)

• 6000 series: 6061, 6082 (good structural strength and weldability)

Technical Advantages of FSW Panels for Marine Applications

1. Excellent Fatigue Resistance

The solid-state welding characteristics of FSW ensure that the weld is almost identical to the base material, achieving a fatigue strength of 80%-95% of the base material, significantly improving the hull's load-bearing capacity and fatigue life. This is particularly crucial for ship structures subjected to wave impacts, hull vibrations, and load fluctuations.

2. Extremely Low Distortion

Traditional fusion welding processes easily lead to plate warping, deformation, and residual stress. FSW, however, only produces a narrow heat-affected zone, causing almost no deformation, ensuring the flatness and dimensional stability of large panels such as decks, bulkheads, and superstructures.

3. Superior Corrosion Resistance

FSW panels primarily use 5000 series marine aluminum alloys (such as 5083 and 5086). Combined with solid-state welding technology, the weld's corrosion resistance is identical to the base material, allowing for long-term use in seawater environments without additional protective treatment.

4. Lightweight for Enhanced Vessel Performance

Aluminum alloy FSW panels can reduce hull weight by approximately 30%-40% compared to steel structures, increasing cargo capacity and reducing fuel consumption while maintaining strength and rigidity. This provides an ideal solution for modern high-speed vessels, patrol boats, and yachts.

5. High Efficiency and Low Cost

FSW enables automated welding and mass production, reducing manual welding and post-processing, improving production efficiency, and lowering material waste and maintenance costs. This is particularly important for projects with tight shipbuilding schedules.

Applications of Marine-grade FSW Ribbed Aluminum Panels

Hull plating/deck/bullspan/bulge plating: FSW-welded aluminum alloy sheets are widely used in the decks and hull structures of vessels such as high-speed boats, ferries, yachts, destroyers, and patrol boats.

Superstructure/hull/modular structure: Marine-grade ribbed aluminum sheets can be used for multi-section building modules, superstructures, and compartment assembly, thereby improving construction efficiency and reducing on-site welding.

Offshore platforms/offshore modules: FSW panels can also be used for oil and gas platforms, offshore structural hulls, and living quarters modules to reduce structural weight, improve corrosion resistance, and simplify installation.