WHAT IS
FRICTION STIR WELDING?

Initially regarded as an experimental process not suited for any practical applications.Invented in 1991 by Wayne Thomas at TWI (The Welding Institute), friction stir welding (FSW) was initially regarded as an experimental process not suited for any practical applications.
Over time, however, it soon became clear that FSW offers numerous benefits in the fabrication of aluminum products that not only rivaled but greatly improved upon traditional fusion welding techniques.
The key difference is that Friction Stir Welding is a solid-state process, which means objects can be joined without reaching the melting point. This innovation in welding technology opened up new doors in fabrication, providing an improved, more efficient, and approach to industrial welding.

FRICTION STIR WELDING VS. CONVENTIONAL WELDING

In Friction Stir Welding, a cylindrical shouldered tool with a profiled pin is rotated and plunged into the joint area between two pieces of sheet or plate material. The frictional heat between the wear resistant welding tool and the workpieces causes the latter to soften without reaching melting point, allowing the tool to traverse along the weld line.
The plasticized material, transferred to the trailing edge of the tool pin, is forged through intimate contact with the tool shoulder and pin profile. On cooling, a solid phase bond is created between the workpieces. This means that FSW can be used to join aluminum sheets and plates without filler wire or shielding gas.

FRICTION
STIR WELDING

Stir Welding 1

TRADITIONAL
FUSION WELDING

Traditional Welding

BENEFITS
OF FRICTION STIR WELDING

  • No need for filler wire or shielding gas
  • Expanded types of welds
  • Improved safety due to the absence of toxic fumes and molten splatter
  • Lower setup costs and less training
  • Great weld appearance and minimal under/over matching
  • Operate in all positions (horizontal, vertical etc.)
  • Use thinner materials with the same joint strength
  • Low environmental impact
  • No cooldown period boosts efficiency and costs

THE PROCESSEXPLAINED

WELDABLE ALLOYS

In Friction Stir Welding, a cylindrical shouldered tool with a profiled pin is rotated and plunged into the joint area between two pieces of sheet or plate material. The frictional heat between the wear resistant welding tool and the workpieces causes the latter to soften without reaching melting point, allowing the tool to traverse along the weld line.

The plasticized material, transferred to the trailing edge of the tool pin, is forged through intimate contact with the tool shoulder and pin profile. On cooling, a solid phase bond is created between the workpieces. This means that FSW can be used to join aluminum sheets and plates without filler wire or shielding gas.

  • STEEL
    STEEL
    • High Strength
    • Pipeline steels (x65, x80, x100)
    • Stainless steel (austenitic, duplex)
    • Automotive (AHSS)
    • Invar
  • COPPER
    • Alloyed elements including Nickel, Zinc, Silicon, Tin
  • NICKEL
    • 200, 600, 625, 718
  • ALUMINIUM
    • 1000, 2000, 3000, 5000, 6000, & 7000
    • Metal matrix composites
  • TITANIUM
    • Commercially pure
    • Alpha Beta

UNIQUE
CHARACTERISTICS

The Friction Stir Weld process involves joint formation below the base material’s melting temperature. The heat generated in the joint area is typically about 80-90% of the material’s melting temperature.

With arc welding, calculating heat input is critically important when preparing welding procedure specifications (WPS) for the production process. With FSW, the traditional components – current and voltage – are not present as the heat input is purely mechanical and thereby replaced by force, friction, and rotation.

Several studies have been conducted to identify the way heat is generated and transferred to the joint area. The quality of an FSW joint is always superior to conventional fusion-welded joints.

IDEAL PARAMETERS

IN PROVIDING PROPER
CONTACT AND ENSURING A HIGH-QUALITY WELD, THE
MOST IMPORTANT CONTROL
FEATURE IS DOWN FORCE.

This guarantees high quality even where tolerance errors in the materials to be joined may arise.

It also enables robust control during higher welding speeds, as the downforce will ensure the generation of frictional heat to soften the material.

When using FSW, the following parameters are controlled: downforce, welding speed, the rotation speed of the welding tool and tilting angle. Only four main parameters need to be mastered, making FSW ideal for mechanized welding

MEGASTIR IS

ALSO THE ONLY FSW SERVICE PROVIDER WITH EXPERTISE TO DESIGN/BUILD TOOLING TO SUPPORT FERROUS AND NON-FERROUS ALLOYS.

THE RIGHT
TOOLS & DESIGN

tool design

Optimizing tool geometry to produce more heat or achieve efficient “stirring” offers two main benefits: improved breaking and mixing of the oxide layer and more efficient heat generation, yielding higher welding speeds and enhanced quality.

UNRIVALED PERFORMANCE

This suggests three alternatives for improving productivity:
  • Increased welding speed compared to conventional processes (GMAW, FCAW, GTAW, SAW,..)
  • Single pass capability on thick applications compared to multi-pass techniques used with competing technologies generates significant cost savings.
  • Superior refined microstructure which is replicates base material providing higher post weld strength and minimized weld distortion.
These benefits, plus others, provide significant cost savings and increased production capacity yielding greater returns for our customers.

MEGASTIR OFFERS TOOLS AND INTELLIGENT TOOL HOLDERS
THAT PROVIDE FULL FUNCTION FRICTION STIR WELDING TECHNOLOGY.

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