FCAW

1. Flux-Cored Arc Welding (FCAW)
An arc welding process that uses an arc between
a continuous filler metal electrode and the weld
pool with shielding from a flux contained within
the tubular electrode or from an externally
supplied gas and without the application of
pressure

2. Flux-cored arc welding (FCAW)
• Flux-cored arc welding (FCAW) is a semi-automatic or
automatic arc welding process.
• FCAW requires a continuously-fed consumable tubular
electrode containing a flux and a constant voltage or, less
commonly, a constant electric current.
• An externally supplied shielding gas is sometimes used, but
often the flux itself is relied upon to generate the necessary
protection from the atmosphere.
• The process is widely used in construction because of its high
welding speed and portability.
• FCAW overcomes many of the restrictions associated with
SMAW.

3. Schematic Illustration for FCAW Process
Welding Direction

4. Types of FCAW
• Self shielding type - that requires no shielding gas
• Flux core in the tubular consumable electrode
• This core contains more than just flux; it also
contains various ingredients that when exposed to
the high temperatures of welding generate a
shielding gas for protecting the arc
• This type of FCAW is preferable because it is
portable and has excellent penetration into the base
metal. Also, the conditions of air flow do not need to
be considered.

5. • Gas shielding type - uses a shielding gas that must be
supplied by an external supply
• This type was developed primarily for welding steels
• Since it uses both a flux cored electrode and an external
shielding gas, one might say that it is a combination of
gas metal (GMAW) and flux-cored arc welding
• This particular style of FCAW is preferable for welding
thicker and out-of-position metals. The slag created by
the flux is also easier to remove
• However, it cannot be used in a windy environment as the
loss of the shielding gas from air flow will produce visible
porosity on the surface of the weld.

6. GAS SHIELD SELF SHIELD

7. Advantages
• FCAW may be an "all-position" process with the right filler
metals.
• No shielding gas needed making it suitable for outdoor welding
and/or windy conditions.
• A high-deposition rate process.
• Some "high-speed" (e.g., automotive applications).
• Less precleaning of metal required.
• Metallurgical benefits from the flux such as the weld metal being
protected initially from external factors until the slag is chipped
away.
• Low operator skill is required.

8. Disadvantages
• Melted Contact Tip – happens when the electrode
actually contacts the base metal, thereby fusing
the two.
• Irregular wire feed – typically a mechanical
problem.
• Porosity – the gases (specifically those from the
flux-core) don’t escape the welded area before the
metal hardens, leaving holes in the welded metal.
• More costly filler material/wire as compared to
GMAW.

10. FLUX CORED ELECTRODE CONFIGURATIONS
BUTT LAP HEART
Metal Core
Flux

11. FLUX CORED ELECTRODE FORMING OPERATION
Strip steel
Flux Hooper
Flux Fill
“U” – Forming Rolls
Closing Rolls
To drawing operation

12. Functions of the Flux Ingredients

14. SLAG SYSTEMS

15. METHODS OF APPLICATIONS &
POSITION CAPABILITIES
 Semiautomatic
 Automatic
 No manual process possible
 All position welding

16. WELDABLE METALS & ALLOYS
• Best wieldable are
• Low carbon steels
• Low alloy steels
• High and medium carbon steels
• Alloy steels
• Certain grades of stainless steels
• Using spl electrodes
• Cast irons
• Nickel alloys

17. WELDABLE THICKNESS RANGES
# Depends on the type of shielding
# Self shielding = Less penetration
 Max penetration is 6 mm
# Gas shielding = Deep penetration
 Max penetration is 13 mm
# But with edge preparation,
 Both types can go upto 19mm

18. JOINT DESIGN

19. WELDING CURRENT
• Similar to GMAW
• DCEP is most used
• DCEN is sometimes used
• DC – CV is the power source
• Current = 50 A – 750 A
• AC can used with spl flux formulations
• CC power supply is then used

22. • Flux-cored electrodes are produced in
diameters ranging from 0.8 to 3.2 mm
• Electrodes for all-position welding may be
available in 0.8 mm , 0.9 mm , 1.2 mm , 1.4
mm , and 1.6 mm
• Electrodes for flat- and horizontal-position
welding may be available in 1.6 mm, 2.0 mm,
2.4 mm, 2.8 mm and 3.2 mm
• Other diameters may be made available by
agreement between the manufacturer and
the purchaser

23. Shielding Gases
Gas can be Inert, Reactive, or Mixtures of both
Gas flow rate is between 35- 45 CFH
Argon and Carbon Dioxide are the main three
gases used in GMAW
 Carbon Dioxide most used
 Carbon Dioxide + Argon mixture sometimes used

24. DEPOSITION RATES & QUALITY OF WELDS
• High deposition rates
• High quality welds

25. LIMITATIONS & APPLICATIONS
• Only for ferrous alloys
• Removal of slag
• Expensive
• Replacing SMAW, GMAW (CO2 version) and
SAW for thinner materials
• Automotive industry, Pipe industry, Tank
industry, General construction industries