6013 Welds Question.

**Bluesman** · 12-06-2011, 10:31 AM

I have NEVER had a problem with welds cracking, however in the past 2 days I've had a couple of instances where a weld would be good and I would clean it with grinder and a few minutes later I would hear a "pop" and sure enough there would be a hairline crack. I would reweld it and had to repeat this process a couple times to finally get it to not crack.

Background on project:

These welds are on a 1/4" thick walled tank that I'm putting "patches" in to cover holes that are unnecessary for this project. The patches are being cut to fit out of some of the same material that was a cut-off from the original tank so that thickness and natural curvature match. Welding it up with 6013's and grinding off smooth so that the patch will be seamless so as to not detract from the overall appearance of the final project.

Is the cracking due to the fact that the joints are super tight and with the curve it causes weld stress from contracting and expanding during weld and cool down?

And, will this be a problem later on while I'm "cooking" on this thing because it is being designed to cook with therefore there will be a lot of heating up and cooling down?

---------- Post added at 11:31 AM ---------- Previous post was at 09:47 AM ----------

I just had this happen a couple more times. Got pissed off and got a 6011, tried to fire it up and it kept sticking couldn't get it started so I flipped machine over to AC and it worked... Don't really understand why the 6011 wouldn't fire up without sticking on DC but I guess that is another question and could have something to do with all the grinding I've been doing on this project as it has seemed to "magnetize" the tank to some degree... Strangest damn thing I've experienced in the shop in awhile...Well, except for scorching my titty nipple the other day...

Anyway, after welding with the 6011 and cleaning it up it had a little more "cut" away than the 6013's did so to fill in some of the undercut I ran a 6013 or two over it (kinda like using them 7018 eraser rods) and then ground it off smooth... Seems to still be holding and hasn't cracked yet. I'm beginning to think it had something to do with high humidity and crazy temps we have been experiencing lately if that makes sense. Maybe with extremely high humidity, rainy weather, and extreme fluctuating temps it affected the expansion/contraction of the steel and since it wasn't a "straight" weld but a curved piece inside another curved piece it may not have been able to contract/expand like it should or either I just wasn't getting enough penetration with the 6013's cause that 6011 damn sure "cut" into the metal quite a bit deeper for sure.

**WookieWelding** · 12-06-2011, 11:16 AM

well if you are getting undercut and not letting the rod fill before you move out of the toes on the weld then yah you are going to get cracking from the stress riser you created with the under cut
you patches are something that i would have beveled to a 22.5 deg tacked them in at the corners ground down the tacks and ran a open root pass with 6010 and a cover with 7018 not a real fan of 6013 since its a really shallow penetration rod
or i would have done the same prep and tig welded it out from the beveled open root

what machine where you trying to run the 6011 on dc with

**Bluesman** · 12-06-2011, 11:24 AM

Originally Posted by WookieWelding

well if you are getting undercut and not letting the rod fill before you move out of the toes on the weld then yah you are going to get cracking from the stress riser you created with the under cut
you patches are something that i would have beveled to a 22.5 deg tacked them in at the corners ground down the tacks and ran a open root pass with 6010 and a cover with 7018 not a real fan of 6013 since its a really shallow penetration rod
or i would have done the same prep and tig welded it out from the beveled open root

what machine where you trying to run the 6011 on dc with

So you are saying it was likely a penetration problem?

I didn't get undercut on the entire 6011 weld, just in a spot or two and it was because I had to speed up and didn't have time for the rod to fill because I was afraid it was about to burn through. Puddle was getting too hot and spread out and if I would have stayed in long enough to let rod "fill" it would have burned through and I would have to patch another hole. as it turned out, the little bit of undercut I got from the 6011 was easily filled with the 6013.

**SICFabrications** · 12-06-2011, 06:13 PM

could also be an alloy problem, wookie..... prolly isnt, but could be.... +1 to what wookie said, not a fan of 6013 for this kind of work. 5p root and eraser cap pass (thems bluesman lingo) the 7018 is a rod that "can" join dissimilar metals... maybe not the best, but it "can"

another reason is the elasticity of the 6013 weld.... it shrinks alot as welded...

how long are you waiting for the part to cool before you grind it all the way down? you really should be letting the weld stay on with some reinforcement (letting the weld bead stand proud a little) if you cant, then you REALLY need to choose a more penetrating rod. dont forget about cattails and also NO SHARP CORNERS!

**Bluesman** · 12-06-2011, 07:22 PM

Thanks guys. I do believe it was a penetration problem since once I got pissed and "went deep" trying to knock the bottom outta her I didn't have narry nother crack. LOL

Sic, I wasn't waiting long at all before grinding cause I was rushing trying to make some sign with the youngins in the shop and they were wanting to help so I was keeping busy while I had their intrest.

O, by the way, what the heck is a cat tail? I'm sure you aren't talking about those marsh plants that the feds get pissed about it you tear up to build pond damn or road beds huh?