Porosity on cap with 7018 Excalibur

[Boilermech]

Ok I was at welding school the other night and done my tig root hot pass and 7018 cap then cut it and bent it and it passed. Ever since then though I kept getting porosity on the cap. My rods were not stored in an oven and are a couple months old. I bought a oven that gets to around 250deg. Can I just put my rods in there and them be ok or do I need to bake them? Here are some pics. Running 3/32 rods at around 90 to 95 amps. I think I might be moving to fast also. I am keeping a really tight arc though (REALLY TIGHT). Is there such a thing as to tight of arc? The first pics are from the un heated rods and the last two are from ones stored in oven at school. Had one area of porosity still and some undercut.






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[geezer]

250 - 300 degrees is for storage, to recondition them you need 500 - 800 degrees for 1 or 2 hours depending on how wet/ damp they are, time to pull out the old grilled cheese electric cooker for those rods

[rake]

Overheating the joint can also cause porosity. To me it looks like you may be running a little too hot.
Those pics look like you were shaking like a hooker in church! Welding pipe is not a race.
Let the joint cool down between passes.

I put old rods on a clean baking sheet and bake them for a couple hours at 450F.
Then into my trusty home made rod warmer. Once the moisture is out of them
it don't take much to keep it out.

[performance]

Yes, you should rebake them. Use your home oven if you need to. A damp rod could possibly cause this issue, but I don't think so because you have one pass that looks better.

A couple of things I see.
1) You could have left the top pass or two off.
2) Too long of an arc length, usually caused by trying to make a rod angle adjustment as you are coming around the pipe. This will almost always cause porosity.

[DVA]

Yes, you should rebake them. Use your home oven if you need to. A damp rod could possibly cause this issue, but I don't think so because you have one pass that looks better.

A couple of things I see.
1) You could have left the top pass or two off.
2) Too long of an arc length, usually caused by trying to make a rod angle adjustment as you are coming around the pipe. This will almost always cause porosity.

First if the rods were wet, look at the instructions on the rods. Many say they need to go to 600 deg F, but moisture on 7018 is more to prevent hydrogen cracking from what I remember.

Starts, stops, and long arcing will be the biggest issue for porosity. It is best to grind or file the starts and stops out. Also, you need to watch your start and stops to ensure they are staggered so large clumps of porosity do not build up.

If you notice that you are long arcing, I would just assume that there is porosity and grind it out.

Also watch your slag as it looks like it can be cleaned off better and if previous passes had slag left behind this could also show up in a bend test.

[Boilermech]

Forgot to mention I am moving the rod in a small u shape on my way around the pipe. Should I just make a strait stringer or is moving it a little ok? This is 2" sch 80 in the 6g position.

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[geezer]

Forgot to mention I am moving the rod in a small u shape on my way around the pipe. Should I just make a strait stringer or is moving it a little ok? This is 2" sch 80 in the 6g position.

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Weaving is OK, but no vertical down, this rod has vertical down as a no, no.

[performance]

a Z may be a better motion. In some applications, they run vert down with this rod.

[geezer]

a Z may be a better motion. In some applications, they run vert down with this rod.

I could tell you a story about vertical down with 7018 which would make you laugh,,vertical down with 7018 gives you a seeping tree sap look on your beads and requires much grinding to clean up the weld,,many many years ago,took me 2 days to weld 48 inches of weld,,lots of grinding,,dam near wore out a new grinder trying to pretty it up,,,but that's another story,,funny when I look back on it...learned to read rod data sheets for their applications,,,since then..

[performance]

I've used vert down many times with 7018 for some fab applications. It makes a nice weld...no weeping sap look. You have to be aware of the slag and watch it to keep it from rolling under, but other wise, despite the lower penetration, the weld looks smooth and as nice as if it were laid in 1G. It may be the amps or arc gap, or possibly the brand that caused the issue. Again, it's not for every situation...but it is used regularly.

[geezer]

I've used vert down many times with 7018 for some fab applications. It makes a nice weld...no weeping sap look. You have to be aware of the slag and watch it to keep it from rolling under, but other wise, despite the lower penetration, the weld looks smooth and as nice as if it were laid in 1G. It may be the amps or arc gap, or possibly the brand that caused the issue. Again, it's not for every situation...but it is used regularly.

Not saying it cannot be done,,depends on the skill of the welder,,back in those days I had neither the skill nor the knowledge,,,would have saved me a lot of grinding if I used a diffent rod or vertical up,,,point is,,there are reasons why things go bad,,,knowing that a rod can only be used for different positions never dawned on me,,,and maybe a few others can learn from reading the rod data sheets,,,I hate grinding,,,but live and learn as they say..

[Mr120]

Grinding sucks and my welding ignorance doesn't help. Reading threads like this is helpful.

[Boilermech]

Ok. If I go and buy some brand new 7018 Excalibur rods then should I just throw them strait into my Keen rod oven or do I need to bake them first. Also can I use them right after I open them or do they need to be warmed up first? Thanks

[Rambozo]

Ok. If I go and buy some brand new 7018 Excalibur rods then should I just throw them strait into my Keen rod oven or do I need to bake them first. Also can I use them right after I open them or do they need to be warmed up first? Thanks

It all depends on how they are packaged. If a vacuum sealed can or retort pouch they can go right into a storage oven. However, if cardboard or plastic packaging, they will need to be baked first for code work. All this is listed on the datasheet for the rods along with the hours at what temp to bake and storage requirements.