FCAW Electrodes for Stainless Steel Welding Welding in Shipbuilding Conference May 10-11, 2011 by Stan Ferree

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

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

Self-Shielded Flux Cored Wires  Generates a Limited Protective Shielding Gas CaF 2, CaCO 3, Na 3 AlF 6, K 2 SiF 6, 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 TiO 2, SiO 2, MgO, Al 2 O 3, 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).

Gas-Shielded Flux Cored: Flat Position  Arc Stabilizers K, Na, Li, Ti compounds Controls arc direction, metal transfer and reduces spatter emissions  Slag Formers TiO 2, SiO 2, Fe 3 O 4, 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/25CO 2 or CO 2 gases. Good for joining in the flat, horizontal positions. Easy to use!

Gas-Shielded Flux Cored: All Position  Arc Stabilizers K, Na, Li, Ti compounds Controls arc direction, metal transfer and reduces spatter emissions  Slag Formers TiO 2, SiO 2, ZrO 2, Al 2 O 3, 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/CO 2 or CO 2 gases in all positions. Easy to use!

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/2O 2 or 95Ar/5CO 2 gases. Easy to use!

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

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

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