[Kentweld]

The slag wont come off as usual, you can forget raking it, and takes a long time to get off with a chisel & Hammer...

I'm welding on a 3mm plate, fillet weld, mill scale is not removed

I've welded alot with these electrodes, and the sweetspot is about 78 amps. Normally, it's no problem at all removing the slag.

IMG_0443.JPG (82.59 KiB) Viewed 1394 times

Here is a bead with 80 amps

IMG_0444.JPG (100.09 KiB) Viewed 1394 times

Tried with 70 amps, and you can see i've been hammering the slag quite alot.

IMG_0442.JPG (119.94 KiB) Viewed 1394 times

First i suspected some moisture in the electrodes, no visual signs, but they have been stored in the garage, inside my toolbox. I then put them in the oven, 200* for 1 hour. Almost fresh out of the oven i tried a new bead, SAME RESULT

Could it be to much heat input? Wrong technique? Some defect in the welding machine? (Almost brand new)

Tomorrow i'm removing all of the mill scale, but i doubt that it could do so much harm...

[AKweldshop]

Do you have some 7018 to try?

I never liked the way 7016 ran.

[Kentweld]

No i just got 7016 rods. 2,5 and 3,2... Never had a problem with them before, but never tried on 3mm steel before..

Could the reason be to much heat into the parent metal? I also have a MIG welder, but i'm low on gas for the moment

I'll find some thicker scrap metal tomorrow, if it goes well that would rule out the 7016's and the machine

[TRACKRANGER]

Hi Kentweld

I have to tell you that the question about using 7018's instead was asked by a totally committed and dyed-in-the-wool 7018 welder. Is there any other rod? Heck no!

However, definitely try AKweldshop's suggestion and use some 7018's and see if that's what makes the difference

Could you have a bad batch of 7016's?

More importantly, have they been kept really dry (in a rod oven)? If not, can you get them in an oven for a day or two and then try them again?

Trev

[Braehill]

Kentweld,
I've only ever welded with a 7016 in an open root uphill progression and the slag came off fairly easy until I got to the 12:00 position. Try it in a vertical up weld and see how it does. I covered it with 8018 fill and cap and it was definitely a nicer root to cover than a 6010 in my opinion. It being a Lo-Hy rod makes moisture it's enemy, so storage is key.

It was made for root pass work if I was informed correctly. There are times when having too much reinforcement on the back side of the weld is not desirable and they have a lower deposition rate than a 7018 but still have the 70k tensile strength making them the best choice.

I know I didn't offer much help there other than drier is better.

Len

[Kentweld]

Thanks for taking the time to reply guys!


Trev:

I did not get the chance to try with 7018, since the project had to be finished today.
I've been storing them in the garage, outside temperatures, but not directly exposed to water or anything. All though, we have pretty moist air here in Norway, so for further storaging, they will be kept inside the house.

Len:

Good info about the rods properties anyways! I've only welded with 7018 two times, when i practiced on the 6G.


Back to the problem.
After keeping the rods inside all night, I did a fillet weld on a 8mm thick angle iron. The result was normal, easy to chip off the slag.

I then removed the mill scale and turned it down to 60 amps (3mm plate). Way better result!

60amps, no mill scale

IMG_0448.JPG (61.01 KiB) Viewed 1324 times

Afterwards i left the mill scale on, still 60 amps. Slag didn't budge. and some nasty arc strikes

60 amps, with mill scale

IMG_0449.JPG (99.05 KiB) Viewed 1324 times

This time i removed the mill scale, but cranked it up to 78 amps, usually a good spot. The result was not all that bad, but it was still harder than usual to get off.

78 amps, no mill scale

IMG_0450.JPG (93.38 KiB) Viewed 1324 times

So the rods were OK. Removing the mill scale helped alot. Reducing the amps helped, but i wont go lower than 60 amps with these rods. Increasing the amps made it more sticky.

The slag came easier off at the start than at the end of the bead, so i think heat is the big sinner.

[Boomer63]

Just a question, are you running DC or AC. Also, a lot of spatter usually indicated long arc, which will give you problems with your slag. Tight, tight arc length with our best friend the 7018.

[Kentweld]

DC, with the electrode on +, earthing on - . I'm keeping the arc pretty tight, but not burying it.

Would it help if i had the electrode on - pole? I'm thaught that if the electrode is at +, it will give more penetration, but never tried the other way around