welding IN 718 to 304 stainless

By Lawrence (*****)

Date 02-11-2009 07:58

For what you describe I"ve seen 347 and Hastelloy W,,,,,, Nothing production, just light fixturing etc.

By Fredspoppy (**)

Date 02-11-2009 14:27

Either Alloy 625 or 82 are the best for the combination you described.

By aevald

Date 02-11-2009 19:37

Hello Zeek, from an un-informed one, is there any possibility that silicon-bronze applied with GTAW could work? I'm looking to learn here as well. Best regards, Allan

By Metarinka (****)

Date 02-12-2009 20:09

We had success using silicone-bronze via GTA on 304L to several grades of inconel.

however nothing structure most for sheet metal applications

By Superflux (****)

Date 02-12-2009 23:39

Not sure about the alloys of Si-bronze available, but I have had hot-short cracking problems (due to the copper content?) using Si-bronze to 304. It was the same filler sculpturers use for their artwork.

By Metarinka (****)

Date 02-13-2009 03:02 Edited 02-15-2009 02:22

I can't speak to your experience but our facility has been using 304L for years in 304L repairs

*edit* I meant to say using silicone bronze to repair 304L

while 304L can successfully be welded with 304L filler their is documented evidence regarding corrosion resistance and cracking due to the low level of ferrite

By Superflux (****)

Date 02-13-2009 04:29 Edited 02-13-2009 20:25

Metarinka,
I am curious as to the particular alloy of Si-bronze you use. Please advise.
I tried to reinvent that wheel with poor results, ie. that wheel got really square looking!
As stated earlier, I was using an artistic grade of Si-bronze and was doing some personal R&D when the hot short problem arose.
Further research into the issue indicated that Chrome and Copper do NOT play well with each other.

By Metarinka (****)

Date 02-15-2009 02:27

it will be a few days until I can answer that as I never specified the repairs with Si-bronze and so I couldn't tell you what specific alloy was used, but I've never heard of any resulting welding issues or hot cracking.

for the record we are talking about welding repairs as well as "bridging" and buttering in gaps with wide fit up. For sheet metal from 22-14 ga. In general these parts don't carry a significant load. I don't think we've had any hot cracking issues primarily as this is a brazed joint and there should be very little if any penatration into the base material.

By Fredspoppy (**)

Date 02-13-2009 13:32

From an engineering/metallurgy standpoint the following general rules apply, when joining dissimilar materials:

(1) within the same family, you can use fillers to match the lower alloy/chemistry, e.g. 90ksi tensile strength carbon/low alloy steel to 70ksi carbon/low alloy steel ,E7018 is acceptable.
(2a) across alloys, you need to use fillers compatible with the higher alloy/chemistry, e.g. any carbon/low alloy steel to stainless steel, choice of correct stainless filler is necessary, e.g. E309 or E310 is acceptable. Depending on application/use of the dissimilar weld joint, a choice of a nickel based filler may be necessary, e.g. alloy 182 or 625 are recommended.
(2b) across stainless steel to high alloys (nickel based), e.g., 304(L)ss to alloy 718, the choice of a compatible nickel based alloy is recommended, that would be alloy 182 or 625.

The above are examples of SMAW fillers. Many filler choices "may work", but, in general, you are best served following the historical recommendations for filler selections in dissimilar base metal joint welding.

By teach Date 02-12-2009 00:37

I have done these welds in the past for mock up for R&D parts and tooling I have found that INCO 625 works best. Usualy 718 requires a post heat treatment for stress reliving when in production. As long as it is not a production part you should be fine