FCAW Electrodes for Stainless Steel Welding

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FCAW Electrodes for Stainless Steel Welding

• Welding in Shipbuilding Conference
• May 10-11, 2011
• by Stan Ferree

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Outline of Presentation

• Description of Cored Stainless Steel Wires
• Welding Application Advantages and Limitations
• Welding Fume Considerations
• Latest Technology Developments
• Summary

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Types of Cored Stainless Steel Wires

• Self- Shielded (EXXXT0-3)
• Gas-Shielded, Flux Cored Flat Position
  (EXXXT0-1,4)
• Gas-Shielded, Flux Cored All-Positional
  (EXXXT1-1,4)
• Gas-Shielded, Metal Cored (ECXXX)
• Ferritic, Austenitic, Martensitic, Duplex

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Self-Shielded Flux Cored Wires

• Generates a Limited Protective Shielding Gas
• CaF2, CaCO3, Na3AlF6, K2SiF6, etc.
• Weld metal nitrogen levels higher than
  gas-shielded types
• Arc Stabilizers
• K, Na, Li, Ti compounds
• Controls arc direction, metal transfer and
  reduces spatter emissions
• Slag Formers
• TiO2, SiO2, MgO, Al2O3, MnO, etc.
• For weld pool protection, bead shape, slag
  detachability welder appeal
• Medium to thick slag coverage
• Alloys (Cr, Ni, Mo, etc.), deoxidizers (FeSi,
  FeMn, FeTi, etc.)
• Excellent for overlays. Good for joining.
  Requires more welder skill than gas-shielded
  types (CTWD A/V vs. FN).

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Gas-Shielded Flux Cored Flat Position

• Arc Stabilizers
• K, Na, Li, Ti compounds
• Controls arc direction, metal transfer and
  reduces spatter emissions
• Slag Formers
• TiO2, SiO2, Fe3O4, MnO, Bi or other similar
  compounds.
• For bead shape, slag detachability and welder
  appeal
• Thin slag coverage
• Alloys and deoxidizers
• Excellent bead shape, slag detachability and
  welder appeal with 75Ar/25CO2 or CO2 gases. Good
  for joining in the flat, horizontal positions.
  Easy to use!

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Gas-Shielded Flux Cored All Position

• Arc Stabilizers
• K, Na, Li, Ti compounds
• Controls arc direction, metal transfer and
  reduces spatter emissions
• Slag Formers
• TiO2, SiO2, ZrO2, Al2O3, MgO, Bi or other related
  compounds.
• For bead shape, slag detachability and welder
  appeal
• Medium slag coverage
• Alloys and deoxidizers
• Good bead shape, slag detachability and welder
  appeal with Ar/CO2 or CO2 gases in all positions.
  Easy to use!

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Metal Cored Wires

• Arc Stabilizers
• K, Na, Li, Ti compounds on inside and/or outside
  of wire
• Controls arc direction, metal transfer and
  reduces spatter emissions
• Other Slag Formers
• Very minimal may contain small additions of
  fluoride compounds
• For bead flow and bridging gaps
• Only very small slag islands like solid wires
• Alloys and deoxidizers
• Good arc stability at low currents, tolerant to
  gaps in thin gauge materials, use with 98Ar/2O2
  or 95Ar/5CO2 gases. Easy to use!

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Advantages - Cored Stainless Steel Wires

• Easier to use than SMAW and GMAW electrodes
• Excellent welder appeal
• Available in custom alloys
• Higher weld metal deposition rates and lower
  overall production costs
• Sometimes more forgiving to joint tolerances or
  gaps

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Limitations - Cored Stainless Steel Wires

• Cost of cored wire vs. SMAW and GMAW electrodes
  need to educate Purchasing and Upper Management
• More difficult to control ferrite with
  self-shielded types
• Removal and disposal of slag vs. GMAW electrodes
• Fume emission rates and Cr(VI) levels are usually
  higher than GMAW electrodes
• Requires shielding gas (on most types), wire
  feeders and related equipment vs. SMAW electrodes

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Latest Technology Developments

• Reducing Cr(VI) emission rates of slag containing
  stainless steel cored wires
• Evaluating arc stabilizers (Li for std. Na and K)
• Flux and metallic modifications to the core
  ingredients
• Shielding gas modifications
• Custom alloys for nuclear and other energy
  related applications, as well as the auto
  industry
• Super austenitic alloys, high nickel alloys, and
  special ferritic grades