filler metal 1

[fazel1]

for welding 304 (austenitic stainless) to 409(ferritic stainless) which filler metal is suitable, E308 or E309?
both of these filler metals produce weld metal of austenitic structure base on schaeffler diagram.

 

[metengr]

I would recommend E309 for this dissimilar weld because you want some level of ferrite to avoid hot cracking in the weld deposit. You do realize that the coefficient of expansion is different between the ferritic stainless and austenitic stainless steel. If the weld joint will be subjected to service temperature fluctuations, I would suggest using a nickel-base filler metal. The expansion of the nickel-base filler metal will be between the ferritic and austenitic stainless steels.

 

[fazel1]

there is some degree of ferrite in both of the weld metal which are produced by these two filler metals.

 

[metengr]

The E308 will develop less ferrite to avoid hot cracking in DMW joints because of the lower chromium and nickel contents. The concern is iron dilution that will result in little to no ferrite to prevent hot cracking during welding. The E308 is typically used for austenitic base materials - like 304.