316 vs 308 filler material GTAW

[Ben22]

Im looking for examples of practical metalurgical reasons for useing 308 instead of 316 filler for welding 304 to 304 using GTAW.

I know about the moly and nickle being higher in 316, and the carbon being lower in 308.

Besides the lower cost of 308 has anyone in this forward been involved in a decision process between the two filler materials.

 

[EdStainless]

Why not use 304L?
Any "L" grade filler will be low C, less than 0.05% and usually well below that.

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P.E. Metallurgy, consulting work welcomed

 

[DVWE]

308 filler metal was developed specifically for welding 304 to 304 base metals. There is no good reason to use 316 filler metal for welding 304 to 304 base metals, unless you like to spend extra money. The trade off of lower moly and nickel in 308 is higher chromium. Carbon is typically the same between the two (0.08 max)

The devil is in the details; she also wears prada.

 

[EdStainless]

It also depends on if you need residual delta ferrite control.
Look at the FN of these fillers.

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P.E. Metallurgy, consulting work welcomed

 

[sandeepKumar63]

As you mentioned already, the main difference is the Moly. Other point is strength. 316L has lower strength compared to 308L (for stick welding rods as per AWS A5.4). Additional this might be useful: Can you weld 316 with 308

 

[weldstan]

In specific corrosion scenario, 316 is subject to metal dusting whereas 308/304 is not.

 

[kingnero]

And there is a certain acid that will attack the Mo in 316 welds on 304 tubing, so you'll eventually see the 316 welds failing on 304 tubing. Have it somewhere in my notes, but it's from theory, not from practical experience.

 

[Dhurjati Sen]

Nothing would happen to the 316 welds.

But do not try welding 316 piping with 308 filler.

DHURJATI SEN
Kolkata, India