Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Welding Fundamentals / Lincoln UltraCore 71A85
- - By Travis Collins (**) Date 09-24-2009 16:35
Does anyone have any advice on the best way to run this wire? We are having trouble with hot cracks in the weld root. It is a thirty degree groove angle with a 3/16" root opening. The process is fcaw. In the flat postion, 29 volts, 300 amps, with a travel speed of 11" per/min, and preheat of 150. Any suggestions would be appreciated.

                                                Thanks
Parent - - By 3.2 Inspector (***) Date 09-24-2009 16:48
Is the groove 30 degree or is it 2*30 = 60 degrees?
If it is only a 30 degree grove, it sounds like solidification cracking.

3.2
Parent - By Travis Collins (**) Date 09-24-2009 18:21
this is a single bevel joint
Parent - - By aevald (*****) Date 09-24-2009 16:52
Hello Travis, what does the base material consist of and what thicknesses are we talking about? Is this something other than A-36? If so, it could be that your preheat needs to be elevated a bit more. Recently worked with A709 50 material and needed to go to 200/250 on the preheats to get away from similar cracking issues. A bit more for your consideration. Best regards, Allan
Parent - - By Travis Collins (**) Date 09-24-2009 18:26
the beam is a grade 992, the bace plate is grade A36. We tried uping the preheat on one pass and it still cracked, although not as bad. At 150 degree it cracked end to end. With 300 degree preheat it was more of a segregated crack. The beam flange thickness is 1" and plate thickness is 1 3/4".
Parent - By aevald (*****) Date 09-24-2009 18:37
Hello again Travis, I believe 3.2 hit on an item that certainly has a lot to do with whether cracking can become an issue or not. If you have a depth-to-width ratio that is too great you could see centerline solidification cracking, similarly, if you are pushing the beads(could result in a troughed bead profile) or lacking sufficient wire speed(amp-to-volt ratios), you might see cracking. I can't recall the specific post, but there was an article included by someone on here that talked of bead profiles, it had to do with SMAW, but could have been speaking of FCAW just as readily. In the article they spoke of how the operators had run troughed profile beads and experienced cracking, by changing the bead profiles to a convex shape the cracking issues were resolved. I would imagine others on here have a better grasp of the post that I am thinking of and could steer you there to consider it. Best regards, Allan
Parent - By strother (***) Date 10-01-2009 12:01
I just got of the phone with welding supplier about this same wire . I am having problems with heat tracks in weld . I don't know if it would apply to your problem but they told me to back down voltage and wire speed Lincoln recomends 24.5 volts  325- 375 wire speed. This wire runs hot, you may be getting too much heat at the crater I've seen that cause cracking. I'm just a welder not an engineer so this is just my opinion based on my experience.
Up Topic Welding Industry / Welding Fundamentals / Lincoln UltraCore 71A85

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill