FCAW Electrodes for Stainless Steel Welding

FCAW Electrodes for Stainless Steel Welding

Welding in Shipbuilding Conference

May 10-11, 2011

by Stan Ferree

Outline of PresentationOutline 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 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 WiresSelf-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).

Gas-Shielded Flux Cored: Flat PositionGas-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!

Gas-Shielded Flux Cored: All PositionGas-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!

Metal Cored WiresMetal 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!

Advantages - Cored Stainless Steel WiresAdvantages - 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 WiresLimitations - 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

Estimated Costs for 6mm V-Up Fillet

$0

$10

$20

$30

$40

$50

$60

$70

$80

$90

$100

$/lb

. Wel

d

Flux Cored GMAW SMAW

$28/lb

$39/lb

$88/lb.

Fume Generation Rate vs. Current

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

100 150 200 250 300 350

Current (A)

FG

R (

g/m

in)

Shield Bright Xtra (CO2)

Shield Bright (75Ar/25CO2)

Arcaloy MC (98Ar/O2)

Arcaloy GMAW (98Ar/2O2)

Core-Bright (Self-Shielded)

%Cr(VI) in Fumes vs. %Cr in Weld

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

16 18 20 22 24 26 28 30

% Cr in Weld

%C

r(V

I)

Shield Bright Xtra (CO2)

Shield Bright (75Ar/25CO2)

Arcaloy MC (98Ar/O2)

Arcaloy GMAW (98Ar/2O2)

Core-Bright (Self-Shielded)

Shield Bright 309L Xtra Cr(VI) vs. Current

75% Ar/25% CO2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

150 170 190 210 230 250 270

Current (A)

% C

r(V

I)

SMAW EXXX-16 Stainless %Cr(VI) in Fumes vs. %Cr in Weld

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

10 12 14 16 18 20 22 24 26 28 30

% Cr in Weld

%C

r(V

I) in

Fu

mes

All Types SMAW Stainless %Cr(VI) in Fumes vs. %Cr in Weld

0.00.51.01.52.02.53.03.54.04.55.05.56.0

10 12 14 16 18 20 22 24 26 28 30

% Cr in Weld

%C

r(V

I) in

Fu

mes

3/32" Core-Bright 309L Cr(VI) GR vs. CO2 and 1/16" Shield Bright 309L Xtra

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

Cr(

VI)

GR

(g

/min

)

NONE CO2 (30 CFH) CO2 (70 CFH) SB 309L (40 CFH)

Shield Bright 309L Cr(VI) GR vs. Gas

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0040

0.0045

Cr(

VI)

GR

(g

/min

)

75Ar/25CO2 90He/7.5Ar/2.5CO2 Tri-Mix

Latest Technology DevelopmentsLatest 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