Flux-cored arc welding is an arc welding process that uses a tubular, powder-filled wire. This flux-cored wire serves both as the electrode and filler material. Depending on the wire type, the process can be carried out with or without external shielding gas. The powder filling creates a protective atmosphere and a slag layer when melted, which stabilises the weld pool.
Principle of Operation
In flux-cored arc welding, a continuously fed wire is melted. The integrated flux generates shielding gas and slag, which shields the weld pool from external influences.
There are two variants:
Self-shielded flux-cored wire (FCAW-S)
• No external shielding gas required
• Very resistant to wind
• Ideal for assembly and outdoor use
Gas-shielded flux-cored wire (FCAW-G)
• Powder filling + additional shielding gas
• Higher weld quality and reduced spatter formation
• Better process control
Areas of Application
• Steel and plant construction
• Shipbuilding
• Repair and maintenance work
• Outdoor and assembly use
• Welding thicker materials
Advantages
• High deposition rate
• Stable arc control
• Can be used partly without shielding gas
• Good gap bridging capability
• Robust and process-reliable in outdoor environments
Disadvantages
• Slag formation and necessary post-processing
• Higher spatter formation than solid wire welding
• Increased fume and emission generation
• Higher wire costs
Similarities and Differences to Electrode Welding (MMA)
Similarities
• Both processes produce slag
• Protection is provided by integrated flux
• Very robust against wind and environmental influences
• Well suited for construction site work
Differences
Wire or Electrode Feed
• Flux-cored wire: continuous wire feed
• MMA: stick electrodes, requiring regular replacement
Productivity
• Flux-cored wire: high deposition rate, long uninterrupted welds
• MMA: lower productivity, more interruptions
Process Stability and Handling
• Flux-cored wire: stable arc, easier to control
• MMA: more operator-dependent
Weld Quality and Repeatability
• Flux-cored wire: consistent weld geometries, more reproducible
• MMA: variable, dependent on electrode and technique
Typical Use Profiles
• Flux-cored wire: preferred for higher demands on speed and quality
• MMA: ideal under extreme conditions, hard-to-reach areas, or contaminated surfaces
Relation to Flux Welding
Flux-cored arc welding belongs to the group of so-called flux welding processes. Flux welding refers to processes in which a flux is used to protect the weld pool and improve arc stability. This flux can appear in various forms, for example as powder filling inside the wire, as coating on a stick electrode, or as loose granules.
In flux-cored arc welding, the flux is located inside the wire. When melted, this creates:
• a protective gas atmosphere (in self-shielded flux-cored wire),
• a slag layer to stabilise the weld pool,
• a cleaned, metallurgically adapted weld pool.
This protective and cleaning effect corresponds to the basic principle of all flux processes.
Classification of the main flux welding processes:
• Flux-cored arc welding (FCAW): flux inside the wire, continuous wire feed.
• Manual metal arc welding (MMA): flux as coating on a stick electrode.
• Submerged arc welding (SAW): thick layer of loose flux granules.
Flux-cored arc welding combines the robustness of flux-based processes with the productivity of continuous wire feed. This results in a welding process that is both flexible and powerful, especially suitable for assembly and outdoor applications.
Distinction from other processes
Flux-cored arc welding vs. MIG/MAG Welding
• MIG/MAG uses solid wire and external shielding gas
• Flux-cored wire uses an integrated flux system
• Different weld pool behaviour and penetration
Flux-cored arc welding vs. MIG Brazing
• MIG brazing is a brazing process with low heat input
• Base material is not melted
• Flux-cored arc welding produces a full weld with metallurgical fusion
Red by Lorch welding machines suitable for flux-cored arc welding:
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