904L Stainless steel - Super Austenitic Or Nickel alloy. Superior corrosion resistance providing they are welded carefully with low heat input (less than 1 kJ/mm recommended) and fast travel speeds with no weaving... Each run of weld should not be started until the metal temperature falls below 100°C... It is unlikely that a uniform distribution of alloy will be achieved throughout the weld (segregation), therefore this material should either be welded with an over-alloyed consumable such as 904L, or a 625, or solution annealed after welding, if maximum corrosion resistance is required...
Due to it's stable austenitic structure, this type of stainless steel is some what more sensitive to hot cracking in connection with welding and generally welding should be performed using a low heat input...
On delivery, sheet, plate and other processed products have a homogeneous austenitic structure with an even distribution of alloying elements in the material... Solidification after partial remelting, e.g. by welding, causes redistribution of certain elements such as molybdenum, chromium and nickel... These variations, segregation, remain in the cast structure of the weld and
can impair the corrosion resistance in certain environments... Segregation tendency is less evident in 904L and this steel is
normally welded using a filler of the same composition as the base material and it can even be welded without filler...
Here's an interesting .pdf covering the welding of stainless steels:
https://www.nickelinstitute.org/~/media/Files/TechnicalLiterature/GuidelinesfortheWeldedFabricationofNickelStainlessSteelsforCorrosionResistantService_11007_.ashxAnd the Avesta Welding Manual:
http://www.kskct.cz/images/materialy/en/avesta.pdfEdit: This welding manual and guide along with an app is from is from Sandvik:
http://smt.sandvik.com/en/products/welding-products/welding-handbook/welding-handbook/http://smt.sandvik.com/en/products/welding-products/welding-guide/There's more but again, I'm tired and gotta get ready for dialysis today so, y'all have a great day!!!
Respectfully,
Henry