Welding guide

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Technical center

Welding stainless steels and nickel alloys is all about cleanliness and choosing the right filler metal. These guidelines are intended as a step-by-step aid to the successful welding of stainless steels and nickel alloys.

  1. Selection of Filler Metal Alloy for Welding Process
  2. Selection of Welding Parameters of the Welding Process
  3. Proper Joint Preparation
  4. Post-Weld cleaning
  5. Special Considerations for Nickel and Superaustenitic alloys
  6. Special Considerastions for Duples Stainless Steels
  7. Welding of Ferritic steels
  8. Weld Overlay
  9. Gas Selection

Selection of Filler Metal Alloy for Welding Process

When both base metals are the same, use the base metal alloy as a guide. For example, if joining 316L to 316L, use 316L filler metal. Past experience may show preferential corrosion in the weld, in which case, moving up in alloy content may be required. Careful consideration regarding how far to move up is necessary, so as not to over-alloy causing galvanic corrosion.

For dissimilar joint welding (example; Stainless Steel to Carbon Steel)

Consideration: Failure can occur as a result of low alloy mixtures if the incorrect filler metal is selected, or if dilution rates are too high. The most common failure mode is cracking but weld embrittlement is also possible.

Proper alloy selection and welding technique are therefore crucial for a successful weld:

  • DO NOT use low alloy electrodes to join low alloy to stainless steel. Brittle welds will result in this practice.
  • DO NOT use lower alloyed stainless steel filler wire to join low alloy to stainless steel. Brittle welds will result in this practice due to martensite formation.
  • DO USE over-alloyed grades such as 309 and 312 types, which are designed specifically for this purpose.

For dissimilar stainless to stainless or nickel to nickel joints see the dissimilar materials joining guide. Generally, best practice is to use the filler metal designed for the higher alloyed of the two. For example, if joining 304L to 316L base metals, use 316L filler metal.

When joining stainless steel to nickel base alloys always use nickel base filler metals.

  • DO NOT use stainless steel filler metals for joining stainless steel to nickel base alloys as there is a very high risk for centerline cracking. This is due to dilution out of the nickel side of the joint. Higher nickel in the stainless weld deposit creates an imbalance in the composition increasing the sensitivity to cracking.