Hardfacing with MIG

I have been doing some rebuilding and hardfacing of a loader leading edge. I rebuilt using wear plate, which was Bn 360 hard. All went well. I pre-heated and used stainless wire with Ar Co2 O2 mix (Argoshield Universal).

I then wanted to hardface both the welds and the face of the wear plate, with cross hatches, as it is "only" 360, whereas the LE is probably at least 500 Bn.

As far as I could see the above gas was OK.

The HF wire I used was 650 Bn "Cobalarc". 1.2mm. The smallest I could get.

I had a lot of trouble with "poking" where the arc was simply not working, so I had to weld very hot to make sure I had a smooth bead.

I found that welding without weave helped. This is actually recommended to prevent the hardface being diluted with the substrate, but the very hot (almost spray) weld of course would make this worse again, and is _not_ recommended.

I also found that I could get better results with a really short stickout. But again this is simply a hotter weld, and has the same problem. Normally, the stickout is a lot less sensitive, and can be used easily to give different weld penetration and bead build.

I was well shielded from breeze, and was using 5 out of a high of 6 voltage settings on the welder (say 200 of 220 A). It rarely gives me this trouble with other welds, and that's usually because of rust/dirt.

There was a lot of black soot on the weld; far more than usual.

I used a new 1.2mm nozzle.

I guess my question is, given that I was pretty careful about cleaning the job, grinding and brushing, what could I have done to help? Other gases?

Thanks for any help. Learning all the time.

***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????
Reply to
Old Nick
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Flux core hard facing wire?

Fitch

Reply to
Fitch R. Williams

Generally hardfacing welds are not supposed to look nice. Getting a nice smooth bead usually results in too much admixture. Every type of alloy is different. It is useful to consult supplier's literature patterns, deposited beads and recommended amperages. Cutting edges often are hardfaced on one side only to allow wear on one side to maintain an edge instead of rounding off.. Also how much preheat did you give it? Randy

Reply to
Randy Zimmerman

This is the correct way to hardface. Consider the cutting edge, hardface the side that wears more if both are left unprotected. If you hardface both sides, it just makes a hard, dull edge. And if the edge is dull or worn down befrteo you start, sharpen or build up (or replace) the edge before hardfacing. On new, painted equipment, using it for just long enough to wear the paint off the edges can give a good idea where hardfacing is needed.

Reply to
Ecnerwal

More like dual-shield hardfacing wire.

I have used it a lot for repair and facing of anvils. I use Rankin's Ranomatic BBG and DDG wires. Great stuff. Much faster than stick rod.

Reply to
Ernie Leimkuhler

snip

The hardfacing wires I have used specified Argon/CO2 shielding gas, and they were quite adamant about it.

The only problem I have had is porosity if you feed too much wire in, or if your wire has absorbed too much moisture.

Keep any unused wire inside a plastic bag, inside another plastic bag.

And throw some uncooked white rice in to absorb any moisture that sneaks in.

Reply to
Ernie Leimkuhler

On Tue, 02 Nov 2004 07:25:32 -0500, Fitch R. Williams vaguely proposed a theory ......and in reply I say!:

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Which leaves me with a $???+ roll of wire :-<

***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????
Reply to
Old Nick

On Tue, 02 Nov 2004 19:31:21 GMT, Ernie Leimkuhler vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

hmmm...need to check for O2 in Universal.

Do that. No porosity. Good solid welds, I ground and hammered them to check and they are as tough as the hobs'a.

OK. Good idea.

Just add oil while welding, season to taste, and have a meal right afterward!

***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????
Reply to
Old Nick

On Tue, 02 Nov 2004 13:56:09 GMT, "Randy Zimmerman" vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

Hah! Got _that_ right anyway. Lumpy.

I was trying not to, as advised. The trouble was I _had_ to get the flat bead to stop this "poking" problem. I did notice that non-weave helped a lot. I just did a couple of runs, if needed.

Yes. Hint taken.

That was all I was doing. I was only working on the under, wear, side, and along the lower lip of the actual leading edge's edge . The other side is bolted to the bucket, so that was a no-brainer. But I can see the point of only welding one side anyway.

Varying amounts up to "water boil", and in a trial, beyond that. Enough to stop cracking, by trial and error. Usually, for dissimilar / high C metals, I work on around 200C. That made little or no difference to my particular problem. They actually warn against too much preheat, to avoid problems with altering the substance of the wear plate, especially as you put in nore heat with the weld.

***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????
Reply to
Old Nick

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