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Up Topic Welding Industry / Technical Discussions / CVN self shielding FCAW electrodes
- - By jwright650 (*****) Date 03-25-2003 19:08
Can someone recommend a FCAW self shielded wire that has excellent impact toughness that would be considered "prequalified"? Esab or Lincoln are brands I'd like to stay with. ASTM A36 and ASTM A572 Gr 50, ASTM A992 are the base metals.
John Wright
Parent - - By DGXL (***) Date 03-26-2003 04:19

I was training 2 guys today with FCAW-S using ESAB Coreshield 8. One guy is seasoned, the other a newbie. They will both test next Tuesday on their 6G's per D1.1. This shop now has a pallet of NR 232 collecting dust in the back.

I'm sure this is all second hand news to you;
I highly recommend the Coreshield 8, easy to run, high Charpy numbers compared to that of Lincoln wire. My next recommendation is the Hobart Fabshield 7018. Not as friendly as the ESAB, but easier for your guys to run than the Lincoln. I'm not sure, but the previous ESAB (Coreshield 6) which ran pretty good too may be extinct, have not inquired about this with Hobart. The ESAB Charpy's will surprise you.

I can still run the NR 232, but I find it difficult to train with when the welders are relatively new at the trade. A few welders I know can actually make this wire talk to them. They really know the feel of this wire on those 3G's/3F's. Most of my clients don't want to fight with the electrode and their looking for user friendly electrodes.
Parent - - By jwright650 (*****) Date 03-26-2003 12:50
I was eyeballing the Coreshield 8Ni1 (E71T-8-Ni1). But in D1.1:2002,Table 3.1 Group II materials, A5.29 has a note 3 that says it is not considered prequalified. Or am I reading this note incorrectly?

Read the note and let me know what your opinion is.

I had heard that the ESAB wire does have better charpy numbers and when submitted to the EOR, it carries better weight when submitted, during the approval process. We do use the Dual Shield 111-AC (3/32") and Dual Shield Arc 71 (1/16") in the shop, but they are 100% CO2 wires.

Thanks for your input,
John Wright
Parent - - By DGXL (***) Date 03-27-2003 15:56
Did a little research on the classification you noted above.
I interprete the D1.1 code (Table 3.1, note 3) as follows:

The electrode you specified is prequalified.

Electrodes with AWS classification of E7XT8-Ni1-B3, B3L, B4, etc. are not prequalified. If you have a copy of A5.29, Table 4 denotes some of these listed in Table 3.1 of the D1.1 as having supplemental designators. An example of non-prequalified SMAW electrode would be: E7018-B2L. Without the additional BXX designators listed in D1.1, Table 3.1, note 3, your electrode would be prequalified and acceptable for use as such.

This note 3 does not prohibit any A5.5, A5.23, A5.28 or A5.29 electrodes from being prequalified, only those with the BXX supplemental designators.

FYI: All of the above AWS specifications listed are for Low-Alloy steel electrodes. All electrodes with the BXX designators require PWHT.
Parent - - By jwright650 (*****) Date 03-27-2003 16:19
Thanks DGXL,
I'll inform the erector that he can submit the ESAB E71T-8-Ni1 to the EOR. He (the erector) wanted to make sure the wire would be acceptable "before" submitting it for approval.

I was alittle shy to recommend a A5.29 wire, I had an EOR shoot the erector down on the wire he was using because the specs for the job only listed A5.1 and A5.20 as electrode specs to use.

I appreciate the leg work,
John Wright
Parent - - By jwright650 (*****) Date 03-28-2003 12:44
I received typical analysis sheets today from ESAB on the Coreshield 8 and the Coreshield 8Ni1. I did notice the Coreshield 8 is a AWS A5.20 spec wire, instead of the AWS A5.29 spec on the Coreshield 8Ni1. Boy, the CVN numbers really jump when you use the Coreshield 8ni1.(@-20F the Coreshield 8 showed 44 ft.lbs. and the Coreshield 8ni1 showed 120 ft.lbs.) That's a good bit of difference. You were right, I was surprised at the CVN numbers!
Have a great day,
John Wright
(wonder if jerry is monitoring this post?)
Parent - - By DGXL (***) Date 03-29-2003 05:11
I've found these numbers to be minimal. Typically, the Charpy's exceed (by quite a bit) what ESAB advertises. The addition of Ni to most of the FCAW electrodes really enhances notch-toughness.
Parent - By GRoberts (***) Date 03-31-2003 15:54
I guess everyones experience is different. I am normally using gas shielded electrodes, but I the data in the catalog almost always exceeds what we get. The electrode manufacturers have a specific way they are required to test (i.e. one or two passes per layer for layer 1, 2 or three passes per layer for layer two and up, 10-17 total passes for .052 through 5/64 wire, etc.) so the electrode perfoms well under these welding circumstanses, but is not guaranteed to perform as well under others. Some of the filler metal companies also have their technique down so that the two layer passes overlap in the middle and their charpys deliberatly include the maximum amount of grain refined weld metal. But once you get it out of the lab, and the test conditions are not very similar to those in the AWS specs, the CVNs (in my experience) drop off.

The addition of nickel is especially beneficial to self shielded electrodes since there are two main ways to improve charpy results. One way is to get really clean metal, and the other way is to add beneficial alloying elements. Since self shielded FCAW by the nature of the process cannot produce very clean weld metal (lots of oxide and nitride inclusions), the easiest way to do it is with the beneficial alloying elements.
Parent - - By DGXL (***) Date 04-09-2003 19:10
Both of the above welders passed today - finally. The lab tested the plates in the wrong direction the first time, and then had to retest. Whew!
Parent - - By jwright650 (*****) Date 04-10-2003 11:12
The Coreshield 8 did OK then. I talked to the erector about the Coreshield 8 and the Coreshield 8Ni1, he was glad to hear that you have had success with the Coreshield 8 already and was looking forward to trying the Coreshield 8Ni1.
Thanks for your input,
John Wright
Parent - - By DGXL (***) Date 04-10-2003 15:04
The guys I talked about previously - one an experienced welder, the other was taking his his very first welding perfomance test, on a 6G(!) and passed. They had me trainging the same 2 guys last year on NR-232, but the newbie could not seem to get it right. Then we tried the Hobart 7018, still no-go. We sectioned the welds in the shop to verify soundness before spending their $$ at a test lab.

Practice had a lot to do with it, but switching electrodes made an immediate and noticable difference. I have been pushing the ESAB electrodes for a few years now and a number of my clients have made the switch. Only new to the forum I guess. I love success stories.
Parent - - By jwright650 (*****) Date 04-10-2003 15:23
The new guy tested on 6G and passed? That's great, experienced welders have trouble with that test. If the new guy passed that test, he should catch on good and make a difference in your work force.
John Wright
Parent - By DGXL (***) Date 04-10-2003 15:33
This guy works for my client. But, his net worth by his employer just increased ten-fold. He went from helper to Class A welder overnight.

I love success stories.
Up Topic Welding Industry / Technical Discussions / CVN self shielding FCAW electrodes

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