Welding Alloy625

[geauxinspect]

I have a pretty basic question I guess... We are going to be doing some welding on a non pressure piece of equipment and it is constructed out of inconel 600. This equipment typically operates between 1400*F and 800*F. We typically use a ENiCrMo3 filler to repair cracking. That is also what the WPS calls out. My question is, would ENiCrMo4 comply or match the chemical properties needed? Thanks in advance!

 

[metengr]

The ENiCrMo4 would be an over matching filler metal in terms of chemical composition to Alloy 625. Can it be welded to Alloy 625, Yes. Is is compatible, it would depend oin the service application. Go to the web site below for additional information for comparing filler metals;

http://www.specialmetalswelding.com/products/electrod/electrod.htm

 

[stanweld]

Due to the Nb content of the ENiCrMo-3, it exhibits superior high temperature strength than does the ENiCrMo-4. NiCrMo-3 will also exhibit less creep ductility due to the same reason.

 

[EdStainless]

One issue is though matching the properties of the base metal. Stronger welds do you no good if they lead to creep failure of the adjacent base metal.

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Plymouth Tube

 

[strider6]

the usual filler metal for Alloy 600 is the Ni 6082 / ERNiCr-3 (Inconel 82). The ENiCrMo-4 is a different nickel alloys (C 276) that is not classified as an high temp nickel alloy.
I'll suggest to use the inconel 82.
I don't know which is you r service but i've found a lot of paper on cracking of alloy 600 and care should be taken in select the correct filler metal.

http://www.specialmetalswelding.com/publica/Special Metals.pdf

http://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/2004/in200408.pdf

S.

http://www.corrosionist.com

 

[weldtek]

The websites listed above are useful, but, if you really want specific recommendations from the experts 800-624-3411.
Of course they prefer you use their products, but, Special Metals offer very good technical support.

 

[geauxinspect]

Well we have a huge issue with cracking inside this piece of equipment! They run this equipment for 6 weeks, and shut it down for 2 days. Going from 1400*F to 90*-110*F... So that alone is not working for us. The company who built the piece used ERNiCrMo3 to construct it. Im in search of a miracle I guess as well as a filler that can handle the operating temp and the cool down rate/routine. The service is a catalyst with a slight hcl content, I'm not sure of the level. Thanks for all of your replies!!

 

[stanweld]

Where is failure occurring? Weld metal? Fusion line? HAZ? Heavy wall to thin wall interface? How many cycles to failure?

 

[geauxinspect]

Fusion Line and HAZ is where we are having our problems... On the hotter side of the equipment.

 

[stanweld]

I recommend that you change the filler metal to ERNiCr-3 or similar Ni-Cr-Fe filler as recommended by strider6; however, the huge delta will limit the number of temperature cycles regardless of filler metal.

 

[geauxinspect]

Well the problems that we are having is from the ERNiCr-3, and it's from when the builders originally built the equipment. The cracks are starting at the haz and one circumferential weld. These cracks are on the side of equip which operates between 1000*F and 1400*F. We have been using a ENiCrMo3 filler and the repairs have been so far successful. BUT we only started to repair them about 6 or 7 months ago. This equipment has been in service for a little over 5 years. So only time will tell if the filler were using is doing what we want it to or not. With all of the experience and knowledge that is shared on this site, I thought I might get some insight on a better filler or some reassurance that im actually using the best one. Again, Thank you for all of your responses. I enjoy reading post on this site!! A ton of knowledge!

 

[weldtek]

With no changes in the process or parameters, it seems unlikely that changing filler will help with problems originating in the HAZ.

 

[geauxinspect]

Well in about 5 years this equipment will have to be replaced. This equipment's projected price to build is close to 1 million bucks... Someone made a comment that if it would have been pwht'd we wouldn't have the problems were having, I dont think that would have helped any at all concidering the cycles. At this point im not sure if anything would...

 

[stanweld]

geauxinspect,
You'll have thermal fatigue problems regardless of whether the tube welds were originally post weld heat treated. Since you've made the repairs with the stronger filler metal, you can only wait to find out when you will need to repair again. Assuming that no change in operating parameters will occur and the current heating and cooling rates will not change, I suspect that the cyclic thermal strains incurred will be more greatly concentrated in the Alloy 600 HAZ or at the fusion line resulting in fewer operating cycles to the next weld repair.

 

[Greekbiker]

I would suggest that you avoid ENiCrMo-3 since the weld metal is succeptible to embtittlement in the temperature range between 650 - 800C (1200-1560F).
A better solution would be a ENiCrFe-3 since it is insucceptible to embrittlement.