317L Overlay Welding Redux 3

[Guest102023]

https://www.eng-tips.com/viewthread.cfm?qid=191359

I've been pondering options for the butter layer for an ultimately 316(L) corrosion-resistant weld overlay to achieve:
[ul]
[li]full 316 Cr-Ni-Mo chemistry in the 2nd layer (getting carbon down to 'L' range is very unlikely);[/li]
[li]achieving a reasonable ferrite number in the 2nd layer of say 4~10FN;[/li]
[li]using GMAW-machine with oscillation or SAW-twin wire (2 x 3/32"Ø side by side; DCSP);[/li]
[li]A516-70 steel substrate[/li]
[/ul]

Minimum 2% Mo is impossible in the 2nd layer without including Mo in the butter layer (especially considering 316L products are typically around 2.2% Mo, so 309L+316L doesn't get you to 2% min. Mo, at least not with conventional weld processes).

317L is not industry standard and it is not one I have used before, but looking at the nominal composition it should be a good candidate. If you take 309L and replace 3.5% of the Cr with Mo you get composition that is surprisingly similar to 317L, and you guarantee 2% min. Mo in layer 2. I'm also considering the difficulty in sourcing 309MoL.

Any thoughts or experiences with using 317L directly on steel?



"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[Guest102023]

EdS,

I am aware there are modified compositions available from Europe specially tailored for overlay. They recognize that 309L was formulated for dissimilar joints and not overlay buttering; that was an afterthought.

In N America I have never seen an 316/L MTR with Mo over 2.3% in ANY product form.


"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[EdStainless]

We used to make SS tube for a customer out of 2.5% min Mo strip, and he welded into assemblies with S31682 that he bought here in the US.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

ESAB has a few wire options at ~3% Mo.

https://esab.com/us/nam_en/products...w/stainless-steel-wires/exaton-19-12-3-lsimo/

 

[Guest102023]

EdS,

Didn't say it isn't possible, I'm just saying they don't give it away.
In 304/L, Cr and Ni are usually much closer to their respective minima.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[kingnero]

Are those the only available welding processes? Can't you work on a lower dilution, giving you more options afterwards?

Especially since you said

Schaeffler says I should be safe at up to around 25%, which I can get with those weld processes.

If you are willing to give up on productivity, you can get much lower than 25% using GMAW, thus giving you a wider array of filler metals to choose from. If you are able to change processes, the problem should entirely dissapear obviously.

 

[Guest102023]

kingnero,

These are proven processes, so try to work with me here; my question was not about process selection.
GMAW with oscillation and SAW-twin wire are high deposition rate and very good quality. What GMAW gives up in productivity it gains in lowest consumable cost. Much depends on the quantity and the part configuration of course.
When doing overlay I also want K.I.S.S., repeatability and fuss-free reliability.


"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[kingnero]

OK, it was just a question...

 

[EdStainless]

Yes Brim, when we buy std 316L strip every heat is 2.00-2.05% Mo.
But it is easier to get high Mo and Cr in 316 than find 317.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Guest102023]

That’s true I’m sure. 317 seems almost like a niche alloy

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[TugboatEng]

ESAB sells 317/317L wire. 3.6% Mo.

https://esab.com/us/nam_en/products...-gmaw/stainless-steel-wires/exaton-19-13-4-l/