Macsteel VRN STEEL

STAINLESS STEEL WELDING
FILLER METALS SUGGESTED FOR WELDING STAINLESS STEELS

AUSTENITIC STAINLESS STEELS

304

As-welded or fully annealed

308

Type 308 weld metal is also referred to a 18-8 and 19-9 composition. Actual weld analysis requirements are 0.08% max C, 19.0% min Cr and 9.0 min Ni. Type 310 weld metal may be used, but the pickup of silicon from the base metal may result in weld hot cracking.

301
304L

As-welded
As-welded or stress-
relieved

309L
347
308L

309
309S

As-welded

309

310
310S

As-welded

309
310

316
316L

316Ti

317L

As-welded or fully
annealed
As-welded or stress-
relieved
As-welded or after
stabilizing and stress-
relieving heat treatment
As-welded or stress relieved

316
310
316Nb
316L
316Nb

317Nb

Welds made with types 316, 316L, 317Nb, and 318 electrodes may occasionally display poor corrosion resistance in the "as-welded" condition.
In such cases, corrosion resistance of the weld metal may be restored by the following heat treatments:
1) For types 316 and 317L base metal, full
     anneal at 1065 - 1120^oC.
2) For types 316L and 317L base metal,
     870^oC stress relief.
3) For 316Nb base metal, 870 - 900^oC
     stabilizing treatment.

321

As-welding or after stabilizing and stress relieving heat treatment

347

Type 321 covered electrodes are not regularly manufactured because titanium is not readily recovered during deposition.

   FERRITIC STAINLESS STEEL

430

Annealed
As-welded

430
308
309
310

Annealing employed to improve weld joint ductility. Weld metal is soft and ductile, but base metal heat-affected zones have limited ductility.

Welding Guidelines
1.    Pre-weld cleaning stainless steel plate with organic solvent or cloth is required.
2.    Avoid mild steel contamination.
3.    Minimise heat input during welding by correct selection of welding parameters and technique.
4.    Post-weld cleaning and passivation is important to ensure optimum corrosion resistance and
       aesthetic appearance.
       (i)      Remove scale from entire weld area, either mechanically or chemically.
       (ii)     Mechanical cleaning - Use dedicated discs, iron-free abrasive, e.g. silica sand.
       (iii)    Chemical cleaning - Pickle weld with HNO₃ + HF formulation followed by thorough washing
                 with clean cold water.
       (iv)     Exersise care during pickling to prevent localised corrosion of the heat-affected zone.
       (v)      Passivation of the entire fabrication may be required in marginal applications or to remove
                  mild steel contamination.