self-shielded flux core welding wire

Date 02-08-2001 01:16

Gentlemen,
Do any of you have experience with the different brands of 71T-8 flux core wires? I'm having a difficult time getting dialed in
with the Lincoln brand of wire that I'm currently using. I'm running a Lincoln SA-250 DC generator with Lincoln recommended
Constant Voltage Adapter and Lincoln's LN-25 voltage sensing wire feeder and 5/64 diameter wire. I get involved in a wide variety of materials and out-of-position welds. I used Lincoln's NR-211(71T-11) wire for years and had very good luck with it, but I understand that that wire is no longer suitable for multiple pass on plate heavier than 1/2" nor will it meet Charpy's for
structuals. All I want is a wire that will match 7018 and run decently with my set-up. Or am I asking too much for a smooth (like 71T-11) running 71T-8. Thanks in advance!

By - Date 02-08-2001 04:46

I don't know why it wouldn't be suitable for multiple passes on plate thicker than 1/2". I took my 1" structure test with that wire. Passed the bend tests both vertical and overhead with no problem. You are right, it is a smooth running wire. I guess what I'm saying, is I'm wondering the same thing as you now.

Slagman

By pipewelder_1999 (****)

Date 02-09-2001 04:05

I think that the reason for the restriction is based on some of the elements in the wire building up in the weld metal. I think the elements are denitrifiers ??? or something like that. Its been 9 years since I had any dealings with NR 211. The deposited thickness limitation is different for various diameters.

I'm pretty sure lincoln has all of this information in their documentation. See http://www.lincolnelectric.com/products/wprod/arccons/fcawss.asp. They should also have the information on their other self shielded wires.

There are some that do have much better impact properties. As far as user appeal I don't know.

Gerald Austin
http://www.geocities.com/pipewelder_1999/

By DGXL

Date 03-02-2001 04:57

Lake,
I saw this post last week, and it did get my attention, I'm just slow responding. I recently gave a seminar on welding processes, part of which is the electrodes avaiable on the market that comply with the current SFRS requirements. One of my handouts was the electrodes that meet the mechanical properties that are desired at the present time by the design community.

I guess it is safe to assume you are using Lincoln's NR232. Anyone who ever picked up a gun and squeezed the trigger for the first time with this electrode had to learn a new, or revise their standard technique used for this electrode.

You should only be concerned about compliance with the electrode specification that is required for specific projects. In other words, if the specs. call for E71T-8, that is your cue to use any electrode that meets that specification. Some engineers are spec-ing electrodes by the manufacture instead of the required AWS specification, this limits who the contractor can do business with as far as consumables.

Now, the following electrodes comply with the E71T-8 specification:
Lincoln NR-232
Hobart Fabshield 7018
ESAB Coreshield 8

These are just a few, there are other electrode manufactures that have FCAW consumables that meet this specification. I have found the Hobart wire to be much more user friendly and not as sensitive to changes in electrical parameters. When I was welding in fab shops, I had a lot of problems with the 232 using the technique I had used for years. It is a good wire, you just have to learn the specific technique required to run it.

There are also some good metal cored electrodes avaiable now (gas shielded) that work quite well also:
Lincoln MC-710
McKay Speed Core 6

These electrodes are great, if you get a chance to use them, try em' out in lieu of solid GMAW electrodes.

One more item, I have contacted many electrode manufactures to obtain data sheets on their electrodes that comply with a particular specification, some will not release this information. This is for any welding consumable or equipment maufacture: IF WE DON'T HAVE ANY INFORMATION ON YOUR PRODUCTS, WHY ARE WE GOING TO PURCHASE THEM? I think holding your cards too close to your chest is not a very good marketing tool! ;-(

Don't feel alone with your problem, we all had to go through the same learning curve. The very best of luck-lake!