17 Current Range (Amps) Unionmelt Performance Flux Group Up To 600 600-800 800-1100 1100-1750 Over 1750 420 Special Good Good N/R N/R N/R 55 Purpose 40 x 150 40 x 150 40 x 150 N/R N/R 85 12 x 200 12 x 200 12 x 200 32 x D N/R 851 12 x 200 12 x 200 12 x 200 32 x D N/R 685 12 x 150 12 x 150 12 x 150 N/R N/R 695 20 x 200 20 x 200 20 x 200 N/R N/R 289 Good Good Good N/R N/R NOTE:  Except for heavy fillet welds, when two or more sizes are listed, the first-mentioned size is preferred. For heavy fillets and plug welds, a fine mesh size is preferred even with low currents. This tends to promote quieter welding action, smoother and wider weld surfaces, less undercutting, and reduced penetration. Finer sizes also produce better weld edge wetting in multipass welds and are used even when low welding currents are employed. N/R — Not Recommended Standard Sizes and Current Ranges of Unionmelt Submerged Arc Fluxes (cont’d.) Rules of Thumb for Flux Selection n Use only neutral fluxes for multipass welds more than 1 inch thick. n Active fluxes are best for limited pass welding, especially over rust and mill scale. n When welding at currents greater than 1000 amps, fused fluxes perform better than bonded fluxes. n Active fluxes should not be used if a weldment has a maximum allowed hardness, especially if the concern is stress corrosion cracking.
Covered
Electrodes
Stainless
Steel
Products
Solid Wire
& Rod
Products
ESAB
TIG & MIG
Wires
Cored
Wire
Products
Submerged
Arc
Products
Hard-
surfacing
Products
Calculations
Filler Metals
ASTM
Steels
Conversion
Tables
Unionmelt
Submerged Arc
Spoolarc
Submerged Arc