Welding of SS 321 and SS 304

[Eabrar]

We are fabricating a tube bundle with SS 321 weld overlay on tubesheet and SS 304 tubes. The recomended wire is of ER-308 in welding standards. My question is that what if I use ER-321 wire instead of ER-308.

Is there any recomendations for this or ER-308 is only recomended due to its lower cost and ER-321 can also be used.

 

[sayee1]

ER321, ER347, ER308 are all applicable for this application if you are talking of tube to tubesheet weld with GTAW process.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!

 

[unclesyd]

Our standard is ER347 in welding 321 to 304 or mostly 304L.
We have had no problems with either base or weld metal with this procedure in a very corrosive service, (HNO3 + Organics @ 120°C).

All welding on 321 is with 347 wire/electrodes due to metallurgical concerns.

 

[sayee1]

Unclesyd,
Just a minor comment. The use of ER321 is restricted to GTAW welding, though I would say it is the first time I am seeing someone refer to using this wire. ER321 cannot be used for SAW because of the problems in transferring Ti across the arc(In SAW using ER321, the recovery of Ti in the weld pool is thus very low). Thus if it were SAW process, I would straight away reject the use of ER321 and call for ER347 which is Nb stabilized. However I could not find any reference in any of my sources restricting the use of ER321 for GTAW welding. In fact refer ASME Section II C and it does classify ER321 and recommends that this wire not be used for SAW.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!

 

[unclesyd]

sayeeprasadr,
I should have qualified my statement a little further. My comments should have been restricted to GTAW, GMAW, or SMAW. The majority of our's and other's welding procedures for 321 SS were developed in the 40's and 50's for use in HNO3 production. The overall consensus was to stay with 347 SS filler metal due to concerns about the loss of Ti as you mention. Other welding and metallurgical concerns entered into the equation but the Ti problem was the driving force due to severe corrosion problems when using 321 SS fillers for HNO3 service.

A majority of the equipment and tanks, exoskeleton, built at that time for our HNO3 service in the early 1950s' are still in service.

We had a lot of fun as the wet end of the our HNO3 plants (4) were constructed of 430 SS and 321 SS.

In the same time frame I worked on developing a Twin Arc A.C. SAW Welding Machine, one of the first. We weren’t able to suscessfully weld 321 SS at the time I left the project for the reasons you state.

 

[marc1000]

Eabrar,

Watch out with just replacing ER-308 with ER-321. Er-308 is slightly more overmatching in Cr than ER-321. So watch out that your welding procedure is OK and you do not loose too much corrosion resistance on your tubesheets because of dilution (I suppose the tubesheet baseplate is C-steel).

 

[Nate101]

ER349 is our prefered for welding 300 series, when the customer allows either. We've seen cracking in 347 in a few rare occations, when using ER347.

 

[PAN]

Nate101,
I know only the different UNS No. for both.
- ER347 (UNS No. S34780)
- ER349 (UNS No. S63197)

In AWS A5.9-1993, there is no information about ER349. Please advise me about the different between ER347 and ER349.

Do you know the reason of cracking in using ER347? Why ER349 can eliminate cracking (compare to ER347)?

 

[metengr]

There is no AWS recognized filler metal classified as ER349.

 

[Nate101]

Sorry I haven’t responded sooner. I took a break from this forum. Metengr is right, but some of our customers allow 349 per AMS5782. According to our welders, they said they have had cracks in the puddle at the end of their joints if they pull the weld rod out too fast. No real proof that what they’re telling me is correct other than all of our welders agree. Nothing in our customer specs saying why the alternative either and they have laid off there welding engineers. As I get a chance I’ll keep digging.

 

[Rich2001]

Nate101, To prevent this crater crack the welders need to use a cracker fill routine. A typical crater fill routine so like this

At the end of the weld-

1. Break the arc.

2. Watch the puddle, it will change to a dull orange (1 or 2 seconds)

3. Re-initate an arc adding a pinch of filler.

(Stop, Wait, Touch)

 

[PAN]

How about the use of ER347Si instead of ER347? Please comment.

 

[PIPERAT]

what is the best tig wire to use if you are welding a335-p9 to 316lss? i think it would be 316 tig wire.

 

[metengr]

You can use ER316 SS, but I would go with a nickel-base filler metal like Inconel 82 (A 5.14 ERNiCr-3).

 

[Nate101]

Rich2001,
They're pretty careful with the ER347, our customers don't allow any cracks in the weld, period. Our welders methods are similar to what you list. 349 seems to solve a little of these problems. We don't have a copy of AWS A5.9, I wish we did, then maybe I could explain the use of 349.
Thanks,
Nathan