Question about Flux Core

By mcphilly Date 06-12-2009 04:27

Hello , I was wonder if someone on here could tell me why it is that flux core wires do not like to run smooth over 7018 . I work as a union Iron worker mainly running coreshield 8 or 232 .....5/64 wire........It has puzzled me for years and I thought I would see if any of you on here could give me an answer ?

We recently started running the Hobart XLR wire and I have to say that it is a very smooth running wire , has anybody used that stuff I guess its pretty new ?

thanks

By dmilesdot (**)

Date 06-12-2009 11:59

If you are asking about running the self sheilding flux core over smaw or vice versa it has to do with the aluminum that is added to the flux core. Its a real incompatable situation with the quality of the completed weld in question.
Dave

By aevald

Date 06-12-2009 17:56

Hello David, do you by chance have a source or resource that could explain that any further? I know that question has been a topic on the forum before and I have also been told that it isn't "OKAY" to run E6010 over E7018 weld deposits, yet it is okay to run E7018 over E6010. On another occasion where these topics came up, there were concerns by a number of folks with repair type situations on equipment or other items or possible remodels in structural situations where there might be compatibility issues with mixing processes from the old to the new. If you have anything you can shed on this I would appreciate hearing about it. Best regards, Allan

By dmilesdot (**)

Date 06-12-2009 18:23

Aevald, my response was more about running self shielded FCAW over SMAW or vice versa as I took this to be the question. My information comes from the "Fabricators and Erectors guide to Welded Steel Construction" written by Omer Blodgett, Scott Funderburk and others. There is a really good explaination under Intermixing of Weld Deposits.
It explains about aluminum pick up by other processes when run over the self shielded FCAW. It seems that the FCAW process uses aluminum as a de oxidizer, while SMAW typically uses manganese-silicon and the two are not compatable. If you were to google the title in parentheses above Im sure you could find the whole article.
Dave

By aevald

Date 06-12-2009 18:43

Thanks Dave

By jeffery19677 Date 07-14-2009 03:45

I'm not Dave, but here's my two cents. The 6010 and 7018 rod , I am told, is the esentially the same steel. The difference is that the 6010 flux allows the steel to cool faster. That makes it harder and more brittle, Whereas the 7018 flux lets the steel cool a little more slowly and makes it softer, allowing it to "give" a little when stressed.
If you put the more brittle metal(6010) over the softer metal,(7018) the difference in the rate of cooling would cause internal stresses of the weld as a whole.
Just my theory.
Jeff

By mcphilly Date 06-13-2009 04:42

thanks guys