A240-321H filler metal

[metaleng123]

Hello all,

Product: Flue Gas Silencer
Design code : Not specified but PQR must be acc. AWS D1.6
Base Material : A240-TP321H
Design temp. : not specified but considering the base metal I'd say between 500 C - 800 C

Question : I'm having trouble chooting a filler metal for this type of steel. My choices are A5.22 E308HT1-1 and A5.9 ER347Si. I know that generaly for welding 321 the go to is 347 because of it's Nb addition, but I'm confused because in all data sheet i read( Lincoln, Bohler, ESAB) ER347Si is regarded as corrosion resistant up to +400 C or simply heat resistant while E308HT1-1 is recommended for service temperatures up to +700 C and for welding 304H, 321H, 347H. What is the right choice here?

Any answer will be much appriciated.

Best regards,

 

[XL83NL]

API RP 577, RP 582 or TR942B provide good background reading on high temp applications using 231H or 347H materials.
Filler metal is not your only concern/point of attention. Things like weld joints design, delta ferrite (FN) etc also matter.
Why is the PQR not acc ASME IX? Id assume that for such applications, the design would follow ASME VIII-1.

Huub
- You never get what you expect, you only get what you inspect.

 

[0707]

TP321H can be welded using E-347H electrodes considering that after welding the weld deposit shall have a FN from 5 min to 11 max before PWHT

 

[metaleng123]

@XL83NL I've looked through API 577 and API 582 and everything points to ER347. We only do the Splitter part of the Flue Gas Silencer, maybe thats why its AWS, but this is a shot in the dark. We're welding plates of 3mm and 5mm thickness, joint designs of II, 1/2V and a2/a3 FW and FN readings are not a requierment for this project even though the temp. is cleary higher than 350 C.

@0707 A5.9 doesen't say anything about ER347H, that was my first thought too. As far as i understand, Aisi 312/321H usually comes with "dual certification" because of it's Carbon %, maybe this is the case for the filler metal too, someone correct me if i'm wrong.FN will most likely be around 8 when using 347 filler.

 

[XL83NL]

Not sure if it’s mentioned already but ER16-8-2 is also a common filler for H-grades, and good low ferrite.

Huub
- You never get what you expect, you only get what you inspect.

 

[gbstanciu]

We have used every time E308H for base material 304H, 321H or 347H

 

[EdStainless]

If the service temp is above 450C use the 347 filler.

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P.E. Metallurgy, consulting work welcomed